Unit 7A
Medical Biotechnology I
Lesson 1
• Disease Detection
• Lecture- Model organisms, biomarkers,
Human Genome Project contribution to
disease detection.
• Create a concept map demonstrating how
designated terms and concepts are related.
Disease Detection
• Models of Human Disease
• Many medical biotechnology
treatments in disease are made
possible because of model
organisms.
• We share a large number of genes
with other organisms.
• Genes in other organisms that
have sequence similarities to
humans are called homologues
• A number of genetic diseases
occur in model organisms.
Disease Detection
•
When researchers study
homologues for diseases,
they are interested in two
things.
1. What does the gene do?
i.e. proteins and molecules
that contribute to the
disease.
2. What happens if gene
transcription is disrupted.?
i.e the disease trait can be
eliminated from the
organism.
3. Genes that have been
eliminated are called
knockouts.
Disease Detection
• Knockouts
• Knockouts are genetically engineered.
• The active gene is either replaced or disrupted
with an inactive DNA sequence.
• Depending on where the inactive DNA
sequence is inserted into the gene, there can
be a variety of outcomes.
• Most often, the trait expression is eliminated.
Disease Detection
• Knockouts
• Engineered genes are inserted into
a blastocyst and it is implanted into a
female mouse.
•Off spring are bred through 2-3
generations until a knockout mouse,
homozygous for the knockout genes,
is produced.
•Often drugs are tested on the
knockout mice. The expectation is
that the drug would have an effect on
a diseased mouse and no effect on a
knockout mouse.
•If the knockout mouse is effected, it
can indicate there would be side
effects in humans.
Disease Detection
• http://learn.genetics.utah.edu/content/tech/t
ransgenic/
• Knockout Mice
Disease Detection
• Examples of model organisms
in detection.
• Ob gene is linked to obesity.
Mice without the Ob gene
become obese. Ob codes for
leptin, which regulates hunger
telling the body when it is full.
• This discovery led to treating
obese human children with
leptin and they have responded
well in preliminary studies.
Disease Detection
• Examples of model organisms
in detection.
• In developing embryos, some
cells must die to make room for
others (apoptosis). How is this
determined?
• A study of C. elegans, a
roundworm, allowed scientists
to determine the fate or
lineage of all of its embryonic
cells. Understanding
programmed cell death has
application to Alzheimer
disease, Huntington disease,
and Parkinson disease.
Disease Detection
• Biomarkers
• For many diseases, early detection is critical.
• One detection approach is to look for
biomarkers as indicators of disease.
• Biomarkers are proteins whose production is
increased in diseased tissues.
• Many biomarkers are released into blood and
urine as a product of cell damage.
• EX. A protein called prostate specific antigen
(PSA) is released into the blood when the
prostate gland is inflamed.
• Elevated PSA levels indicate inflammation and
even cancer.
• Many companies are working on a variety of
biomarkers that can be used in disease
detection.
Disease Detection
• Human Genome Projects
• Prior to the Human
Genome Project, about 100
disease could be tested for.
• Now there are genetic tests
for over 2,000 diseases.
• The HGP developed
chromosome maps showing
locations of normal and
diseased genes.
Chromosome 4
Lesson 2
• Disease Detection: Testing
• Work in groups of 4. Read powerpoint on
amniocentesis, RFLP analysis, SNPs, and microarray.
• Discuss content with your group and respond to
questions.
• Watch animation for Amniocentesis , RFLP analysis,
SNPs
• Complete Questions
• Complete SNP activity.
• Complete Microarray Simulation
Genetic Testing
Amniocentesis
• Until recently, most genetic testing occurred on fetuses to
identify gender and genetic diseases.
• Amniocentesis is one technique used to collect genetic
material for genetic testing.
• When the developing fetus is around 16 weeks of age, a
needle is inserted into the mother’s abdomen into a pocket
of amniotic fluid that surrounds and cushions the fetus.
Amniotic fluid is removed.
• The fluid contains cells from the fetus, such as skin cells.
• Skin cells are cultured to increase their number.
• Mitotic chromosomes are removed and stained to create a
karyotype
• http://www.youtube.com/watch?v=bZcGpjyOXt0
Genetic Testing
• Chorionic Villi Sampling
• Chorionic villi Sampling (CVS) can also be done to
diagnose genetic disease in fetuses who are 8 -10
weeks in age.
• A suction tube removes a layer of cells called the
chorionic villus, tissue that helps make up the
placenta.
• CVS collects enough cells so a karyotype can be
made from the cells retrieved.
• http://video.about.com/pregnancy/ChorionicVillus-Sampling.htm
Genetic Testing
• Karyotypes
Genetic Testing
• Karyotyping can be
carried out with adults.
• Typically blood is drawn
and white blood cells
are used.
• Fluorescence in situ
hybridization(FISH) is
used.
• Chromosomes are
hybridized with
fluorescent probes.
Genetic Testing
• Karyotypes
• FISH can be performed with
probes that fluoresce
different colors.
• This is called spectral
karyotyping.
• It is very useful in identifying
missing parts of
chromosomes, extra
chromosomes, and
translocation mutations.
Genetic Testing
• RFLP Analysis
• Most genetic diseases result from gene mutations rather than
chromosomal abnormalities
• The basic idea behind restriction length polymorphisms
analysis (RFLP) is that a defective gene may be cut differently
than its normal counterpart by restriction enzymes.
• If DNA from a healthy individual (HBB gene) and DNA from an
individual (HBB gene) with sickle cell disease are cut by
restriction enzymes, the fragments will be different sizes
because the base sequences are different.
• DNA from a patient is subjected to restriction enzymes and
the DNA fragments undergo gel electrophoresis.
• Patient DNA fragment length is compared to normal fragment
lengths to diagnose disease
• http://highered.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/d
l/free/0072437316/120078/bio20.swf::Restriction%20Fragm
ent%20Length%20Polymorphisms
Genetic Testing
• RFLP Analysis
Genetic Testing
• Single Nucleotide Polymorphisms
• 99.9% of DNA sequencing is identical in humans.
• One of the common forms of genetic variations (in the .1%) in humans is
called the single nucleotide polymorphism.
• SNPs are single nucleotide changes that vary from person to person.
• SNPs occur about every 100 to 300 base pairs and most of them are in
non coding regions of DNA.
• If a SNP occurs in a gene sequence, it can produce disease or confer
susceptibility for a disease.
Genetic Testing
• SNPs
• Because SNPs occur frequently throughout the genome, they are
valuable markers to identifying disease related genes.
• SNPs are being used to predict stroke, cancer, heart disease, and
behavioral illnesses.
• Many groups of SNPs on the same chromosome are called a
haplotype.
• The HapMap project is identifying and cataloguing the
chromosomal location of over 1.4 million SNPs present in 3 billion
base pairs of the human genome.
• Complete the SNP activity.
http://www.pbs.org/wgbh/nova/teachers/activities/0302_01_nsn.h
tml
Genetic Testing
• DNA Microarray
• DNA microarrays are called
gene chips.
• They are a key techniques to
studying genetic diseases.
• Researchers use microarrays
to screen a patient for a
pattern of genes that might
be expressed in a particular
disease.
Genetic Testing
• DNA Microarray
• An example of a use for DNA microarray
would be a comparison of healthy and
cancer cell DNA.
• mRNA from both types of cells is isolated.
• c DNA is synthesized from the mRNA in each
cell type using reverse transcriptase.
• cDNA is labeled with a fluorescent dye and
is applied to a microarray slide; different
color dye is used for cancer and healthy
cells.
• The slide has up to 10,000 “spots” of DNA
on it; each represents unique sequences of
DNA for a different gene.
• The slide is incubated overnight and the
cDNA hybridizes to complimentary DNA
strands on the microarray slide.
Genetic Testing
Genetic Testing
• DNA Microarray
• The slide is scanned by a laser that
causes the dye to fluoresce when
cDNA binds to gene DNA on the
slide.
• The fluorescent spots indicate
which genes are expressed in the
cells of interest.
• Gene expression patterns from
each of the cell types is compared
to see which genes are active in a
healthy cell and which are active in
a cancer cell.
• Results of microarray studies can
be used to develop new drugs to
combat cancer and other diseases.
Genetic Testing
• http://learn.genetics.utah.edu/content/labs/
microarray/
Visit the virtual DNA microarray simulation for a
detailed description of the procedure.
Lesson 3
• Case Study: Pharmacogenetics.
• Powerpoint introduction
• Work in groups of 4 to read and discuss each
section of the pharmacogenetics case study.
• Respond to case study questions.
• Whole class discussion of responses.
Pharmacogenetics
• Pharmacogenetics
• With information from genomics and
genetic testing such as SNPs and
microarray, a new field that studies how
the genome is affected by and responds to
different drugs has emerged.
• This new field is called pharmacogenetics.
• Pharmacogenetics uses genetic testing
information to design a personal drug
treatment plan based on an individual’s
genetic variations.
• Genome tailored drug treatments could
reduce drug side effects, drug interactions,
and even death.
• http://sonet.nottingham.ac.uk/rlos/cetl/ph
armacogenetics/
Lesson 4
• Treatments for Disease
• Lecture- Nanotechnology, Artificial Blood, and
Monoclonal Antibodies.
• Powerpoint presentation of content.
Nanotechnology
• For homework:
• Visit the following website and respond to
questions.
• http://www.nano.gov/nanotech-101
Nanotechnology
• Nanotechnology :
Understanding and
controlling of matter at the
nanoscale; dimensions
between approximately 1
and 100 nanometers, where
unique phenomena enable
novel applications.
• Encompassing nanoscale
science, engineering, and
technology, nanotechnology
involves imaging, measuring,
modeling, and manipulating
matter at this length scale.
Nanotechnology
• Matter such as gases, liquids, and solids
can exhibit unusual physical, chemical,
and biological properties at the
nanoscale, differing in important ways
from the properties of bulk materials
and single atoms or molecules.
• Some nanostructured materials are
stronger or have different magnetic
properties compared to other forms or
sizes or the same material.
• Others are better at conducting heat or
electricity. They may become more
chemically reactive or reflect light better
or change color as their size or structure
is altered.
Nanotechnology
•
•
•
•
•
•
Nanoparticles such as
Iron
Gold
Liquid crystals
And others
Are nanoparticles that can be used in medical
applications.
• Some of these compounds can be inert at the
“macro” level but become catalysts at the
nanoscale. In addition, they easily penetrate
cells (soluable) and interact with cellular
molecules.
Nanotechnology
•
•
•
•
•
•
•
•
A nanoparticle called a microsphere is of
particular interest in medicine.
It is composed of a phospholipid bilayer to
which drugs can be attached.
The microspheres can target specific cells
and deliver needed drugs.
Advantage: They can dissolve in the body.
Examples
Researchers are investigating ways to
implant microspheres holding anticancer
drugs next to tumors.
Researchers are working on ways to attach
microspheres to wafers for pain
anesthetics
Microspherse called liposomes are being
used in gene therapy.
Nanotechnology
• View the animations about nanotechnology
• http://nano.cancer.gov/learn/understanding/video_journey.asp
• http://www.azonano.com/nanotechnology-videodetails.aspx?VidID=437
• http://www.azonano.com/nanotechnology-videodetails.aspx?VidID=480
• http://www.azonano.com/nanotechnology-videodetails.aspx?VidID=469
Artificial Blood
• Blood transfusions in the
United States are routinely
screened for pathogens like
the HIV virus, and the
Hepatitis B and C virus.
• In other parts of the world,
blood screening procedures
are not as good.
• This has prompted scientists
to develop artificial blood or
blood substitues.
Artificial Blood
• Major Advantages of Artificial Blood
1. It is a disease free alternative.
2. It is in constant supply without
shortages.
3. Available for emergency situations.
4. Can be stored for a long period of
time. (Blood needs to be refrigerated
and lasts 42 days. Artificial blood can
last up to 3 months unrefrigerated.
5. There would be no recipient rejection
as there are no antigenic molecules in
artificial blood.
Artificial Blood
• Major Disadvantage
1. Artificial Blood serves one
primary purpose; it is designed
to carry oxygen.
•
Normal red blood cells have
other functions. In addition to
carrying oxygen, they are a
source of iron and have a role in
eliminating carbon dioxide from
the blood.
Artificial Blood
• Currently there are 2 major types
of artificial blood:
1. Hemoglobin based: Made from
cow or human blood. Blood is
process and hemoglobin is
purified.
2. Fluorocarbon based:
Fluorocarbon emulsions are made
with particles about 1/40 size the
red cells. The fluorcarbon binds
to oxygen in a fashion similar to
hemoglobin.

• There is some newer research
which is combining the oxygen
carrying portion of the
hemoglobin molecule with a
polymer shell!
Monoclonal Antibodies
• Monoclonal antibodies are specific antibodies
targeted towards the specific molecular
structure on an antigen (epitope) that causes
the immune response
• Treating patients with monoclonal antibodies
can be effective in transplant rejection,
cardiovascular disease, some allergies, and
certain cancers like breast cancer.
Monoclonal Antibodies
How they are made
Monoclonal Antibodies
• A mouse is injected with an antigen and B cells (plasma
cells) produce antibody.
• The spleen of the mouse is removed and the B cells are
mixed with myeloma cells (cancerous). Myeloma cells
won’t stop dividing.
• B cells and myeloma cells merge and become
hybridomas.
• Hybridomas are antibody manufacturing factories.
• Antibodies are isolated and given to patients.
• http://highered.mcgrawhill.com/sites/0072556781/student_view0/chapter32/
animation_quiz_3.html
Lesson 5
• Webquest: Gene Therapy
• We will be visiting the website listed below:
• http://learn.genetics.utah.edu/content/tech/g
enetherapy/
• Research University of Utah Genetics website
to study multiple aspects of gene therapy.
• Respond to questions on your handout.
Lesson 6
• Gene Therapy Project – Market a Vector
• Using information from gene therapy
webquest, you will work with a partner and
design a powerpoint and brochure to market a
gene therapy vector to research scientists.
• You will present your powerpoint to class and
distribute brochures.
• Refer to your handout for details.
Lesson 7
• Group work – Stem Cells
• The topic of stem cells has been addressed in introductory
biology . This lesson is a review and refresher for
previously learned content.
• Work in groups of 4 to review the powerpoint on assigned
section of content. Develop review questions for content.
• Teacher will approve all review material.
• Reassign one “expert” from each group assignment to a
new grouping.
• New group will review powerpoint together, discuss
content and review questions.
• Teacher will provide a written quiz at the end of the
assignment.
Stem cells
• Totipotent Stem Cells
• These are the most versatile of the stem
cell types. When a sperm cell and an egg
cell unite, they form a one-celled fertilized
egg. This cell is totipotent, meaning it has
the potential to give rise to any and all
human cells, such as brain, liver, blood or
heart cells. It can even give rise to an entire
functional organism. The first few cell
divisions in embryonic development
produce more totipotent cells.
Stem Cells
• Pluripotent Stem Cells (Embryonic Stem Cells)
• These cells are like totipotent stem cells in that they
can give rise to all tissue types. Unlike totipotent stem
cells, however, they cannot give rise to an entire
organism. On the fourth day of development, the
embryo forms into two layers, an an outer layer which
will become the placenta, and an inner mass which will
form the tissues of the developing human body. These
inner cells, though they can form nearly any human
tissue, cannot do so without the outer layer; so are not
totipotent, but pluripotent. As these pluripotent stem
cells continue to divide, they begin to specialize
further.
Stem Cells
• Multipotent Stem Cells
• These are less plastic and more
differentiated stem cells. They give
rise to a limited range of cells within a
tissue type. The offspring of the
pluripotent cells become the
progenitors of such cell lines as blood
cells, skin cells and nerve cells. At this
stage, they are multipotent. They can
become one of several types of cells
within a given organ. For
example, multipotent blood stem
cells can develop into red blood cells,
white blood cells or platelets
Stem Cells
• Adult Stem Cells
• An adult stem cell is a multipotent
stem cell in adult humans that is
used to replace cells that have
died or lost function. It is an
undifferentiated cell present in
differentiated tissue. It renews
itself and can specialize to yield all
cell types present in the tissue
from which it originated.
Stem Cells
• Induced Pluripotent
Stem Cells (IPsCs)
• IPSCs are differentiated
cells that have been
reprogrammed back to
pluripotent stem cells.
• The introduction of 4
genes OCT3/4, SOX2, cMYC, and KLF4 by a
retrovirus into cells
reprograms the cells into
an earlier stage of
differentiation similar to
embryonic stem cells.
• These genes encode
transcription factors
involved in cell
development.
Stem Cells - IPSCs
Stem Cells
• IPSCs
• IPSCs can be used for patient specific
therapies without the risk of cell rejection.
• Cells could be taken from a patient,
reprogrammed into an IPC, and then
differentiated into a cell that could combat
disease in the patient.
• There would be no need for embryonic stem
cells.
Stem Cells
• IPSCs
• Scientists still do not fully understand
how to control induced pluripotent
stem cells.
1. They do not understand the degree of
pluripotency in these cells.
2. Producing them is inefficient. 1 in
1000 cells exposed to a
reprogramming approach becomes
an IPSC.
3. The cells require constant feeding in
cell culture.
4. The cells have low viability after they
have been frozen for storage.
5. The cells are prone to forming
tumors.
6. Occasionally, IPSCs spontaneously
revert to differentiated cells.
Stem Cells
• Stem Cell Therapies
• Potential and promise are two words frequently
used to describe stem cell therapies.
• The most promising application to date has been
for leukemia.
1. Patients receive chemotherapy or radiation to
destroy cancerous white blood cells.
2. Patients receive WBC stem cells which
proliferate to normal cells.
Stem
Cells
Stem Cell Therapy
•
• Researchers have injected
stem cells from different
sources into damaged
heart tissue of mice
(heart tissue does not
repair itself well). The
stem cells developed into
cardiac muscle and
improved heart function
by 35%. This work shows
promise for human heart
attack victims.
Stem Cells
• Stem Cell Therapy
• Researchers have demonstrated that embryonic
stem cells can be differentiated to form neurons
in mice to show improvement in spinal cord
injuries. The FDA has approved the first clinical
trial for the use of embryonic stem cells to treat
humans with spinal cord injuries.
Stem Cells
• Challenges for stem cell therapy
1. Controlling differentiation –When stem cells are injected
scientists cannot control the spread of cells to other
places in the body nor can they control the differentiation
of stem cells into tissues other than those that were
intended.
2. Injected human embryonic stem cells tend for form
tumors.
3. Chromosomal abnormalities – Abnormality in
chromosome number( trisomy) occurs frequently when
stem cells differentiate
• The most promising therapy appears to be differentiating
the stem cells in vitro and them injecting them.
Stem cells
• Visit these websites
• http://www.sumanasinc.com/webcontent/ani
mations/content/stemcells_scnt.html
• http://www.dnalc.org/resources/animations/s
temcells.html
• http://www.youtube.com/watch?v=cPvidAvz
mx0
Lesson 8
• Leukemia Webquest
• Research leukemia website.
https://sites.google.com/site/stemcellsinaction/h
ome/stem-cell-webquest-directions
• Respond to questions.
• Write one paragraph: Why has leukemia stem
cell therapy been successful while other types of
stem cell therapies have failed?
Lesson 9
• Debate: Should embryonic stem cells be used as research
tools?
• Work with a partner and read research articles on stem cell
social policy. Discuss the pros and cons of the argument
with partner.
• Work in groups of 4 on assigned topic. Research on
computer additional information to support your topic.
Develop a 5 minute argument defending your position.
• Debate: One person from each group will present pro or
con argument. Instead of rebuttal, members of the
audience will each have to speak about their opinion on
stem cell social policy. Class will vote at end of debate.
Unit 7B
Medical Biotechnology II
Lesson 1
• Introduction: movie “Contagion”
• Discussion: Is this movie realistic with regards
to how diseases in spread, how governments
respond, and the availability of vaccines?
• http://www.movie2k.to/Contagion-watchmovie-1033665.html
Lesson 2
•
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•
•
Infectious
Classification, transmission, prevention
Lecture; Read and study powerpoint
Work with a partner and develop review
questions
• Whole class discussion of review questions.
• Gram Stain Lab: Normal Flora
• Case Study: Childbed fever
Infectious Disease Classification
• Epidemiology: the study of when and where
diseases occur and how they are transmitted.
• Pathology: The study of disease
• Etiology: The study of the cause of a disease
• Infection: Colonization of the body by
pathogens
• Disease: An abnormal state in which the body
is not functioning normally.
Infectious Disease Classification
• Normal Flora and the Host
 Normal Flora or Normal
Microbiota: The normal
bacteria found in or on your
body; mostly nonpathogenic
 Normal flora can become
pathogenic when it colonizes
areas of the body that it is not
normally found in; ex. E. coli in
the bladder instead of the
intestines.
Infectious Disease Classification
• Normal
Microbiota and
the Host
• Locations of
normal
microbiota on and
in the human
body.
Infectious Disease Classification
• Where does normal
flora come from?
• Environment, family
members etc.
• Fetus in the uterus is
germ free.
• At birth, Lactobacilli
from the vagina
colonize the baby’s
digestive tract.
Infectious Disease Classification
• Transient Flora and the
Host
• Transient Flora:
Bacterial changes of
normal flora due to
seasonal changes
(temperatures, etc.) or
age and activity.
Infectious Disease Classification
 Can normal flora benefit the host?
 Microbial antagonism: how microbes
inhibit the growth of other microbes,
usually by competition (e.g.
bacteriocins).
 Bacteriocins: chemicals produced by
bacteria to inhibit the growth of other
bacteria (normal flora produce a lot of
this).
 Probiotics are live microbes applied to
or ingested into the body, intended to
exert a beneficial effect.
Infectious Disease Classification
• Symbiosis
• Symbiotic relationship:
organisms living in a close,
intimate relationship with
each other.
– Commensalism, one organism
is benefited and the other is
unaffected. (Normal flora).
– Mutualism, both organisms
benefit. (Normal flora).
– Parasitism, one organism
benefits at the expense of the
other. (Infectious disease)
Infectious Disease Classification
• Pathogen
• A pathogen or infectious agent is a
biological agent that causes disease or
illness to its host.
• The term is used for agents that
disrupt the normal physiology of a
cell, fungus, animal or plant.
• A pathogen can be viral, bacterial,
fungal, or a prion.
• A “primary pathogen” is defined as an
organism capable of causing disease
in a healthy person with a normal
immune response.
• A “secondary pathogen” is an
infectious agent that causes a disease
that follows the initial infections.
Infectious Disease Classification
• Opportunistic Pathogen
• Opportunistic Pathogen :
Potential pathogenic
organisms that do not
ordinarily cause disease in
the normal habitat of a
healthy person.
• When these organisms get
into an area where they are
not normally found and
cause disease.
• All normal flora are have the
capacity to be an
opportunist in a
compromised host (one
without normal immune
response).
Transmission Infectious Disease
• Reservoirs of Infection
• For a disease to perpetuate itself, there must
be a continual source of disease. This
continual source is referred to as the
reservoir.
• Reservoirs are classified as either human,
animal or nonliving.
Transmission Infectious Disease
• Reservoirs of Infection
 Reservoirs of infection are continual sources
of infection.
 Human — AIDS, gonorrhea
 Carriers may have inapparent infections
or latent diseases.
 Animal
 Zoonoses. Diseases that occur primarily in animals.
Example Rabies, Lyme disease, toxoplasmosis, influenza
 Nonliving —
 Soil: Botulism, tetanus
 Water: Cholera
Transmission Infectious Disease
Contact transmission.
1. Direct contact: Person to person transmission by physical contact.
This includes touching, kissing and sexual intercourse.
2. Indirect contact Disease is transmitted from a nonliving object
(fomite) to a host.
- Fomites may include eating utensils, toys, towels, door
knobs, etc.
3. Droplet transmission. Mucous droplets from coughs sneezes
laughing or talking. Droplet travels less than one meter from the
reservoir to host.
- Example Whooping cough, Influenza, the Common Cold.
Transmission Infectious Disease
Transmission Infectious Disease
• Vehicle: Transmission by an inanimate
reservoir
- Food: E. coli gastroenteritis (fecal/oral)
- Water: Cholera (fecal/oral)
- Airborne: Anthrax
• Vectors: Arthropods, especially fleas, ticks,
and mosquitoes.
- Plague, Lyme disease
Transmission Infectious Disease
Prevention
•
•
•
•
Vaccines
Antimicrobial drugs
Handwashing
Sanitation of fomites and water
supplies
• Prepare and store food properly
• Control pests (insects and
rodents)
• Quarantine
Lesson 3
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Part 1 – Stages of Infection
Read powerpoint online
Work with a partner to develop review questions.
Whole class discussion questions.
Read article about stages of infection, traditional medical tests, and
molecular biology tests used to diagnose.
Part 2 – Epidemiology
Read SARS time line (Refer to handout)
What types of activities occur during an epidemic
Read powerpoint online.
Write a one paragraph description of the important elements in an
epidemiological investigation.
View video –SARS The True Story
Class discussion
Stages of Infection
• How Infectious Agents
Cause Disease
• Production of poisons,
such as toxins and
enzymes, that destroy
cells and tissues.
• Direct invasion and
destruction of host cells.
• Triggering responses
from the host’s immune
system leading to
disease signs and
symptoms.
Stages of Infection
1. Entry of Pathogen
– Portal of Entry 
2. Colonization
– Usually at the site of
entry
3. Incubation Period
– Asymptomatic period
– Between the initial
contact with the microbe
and the appearance of
the first symptoms
Stages of Infection
4. Prodromal Symptoms
– Initial Symptoms
5. Invasive period
– Increasing Severity of
Symptoms
– Fever
– Inflammation and Swelling
– Tissue Damage
– Infection May Spread to
Other Sites
– Acme
Stages of Infection
6. Decline of Infection
- Improvement in
symptoms
7. Convalescence
Diagnostic Tests- Traditional
• Isolation of Pathogens from
Clinical Specimens
• If a physician suspects a
bacterial infection, samples of
infected body fluids or tissues
are collected from the patient.
• Samples may include blood,
spinal fluid, pus, sputum, urine,
or feces.
• A swab may be used to sample
the infected area.
Diagnostic Tests - Traditional
• Isolation of Pathogens
from Clinical Specimens
• The swab is then
inoculated onto the
surface of an agar plate or
put into a tube of liquid
medium.
• The bacteria is grown and
isolated.
Diagnostic Tests-Traditional
• Isolation of Pathogens
from Clinical
Specimens
• The bacteria is
identified by growth
dependent rapid
identification systems.
• These systems contain
a battery of
biochemical tests.
Diagnostic Tests-Traditional
• Isolation of Pathogen from
Clinical Specimen
• Identified pathogens are then
tested for sensitivity to
antimicrobial agents.
• Drug sensitivity testing guides
antimicrobial therapy for the
patient.
• Small wafers with antibiotics are
placed on a plate of bacteria.
Large zones of no bacterial
growth indicated antimicrobial
sensitivity.
Diagnostic Tests- Traditional
• Serology Tests for Antibody or
Antigen (Bacterial & Viral)
• The agglutination of antigen coated
or antibody coated latex beads with a
complimentary antibody or antigen is
a typical method of rapid diagnosis.
• Blood serum from the patient is used
in this test.
• If , for example, a patient has
antibody to a particular infectious
agent, the antibody will bind to the
antigen coated latex beads.
• The suspension becomes visibly
clumped.
http://www.youtube.com/watch?v=h
RzOwSTkF0s
• (first 3 min)
Diagnostic Tests- ELISA
• Enzyme Linked Immunoassay (viruses)-ELISA
• A target antigen is bound to a solid phase such as the
plastic on a microplate.
• A patient’s blood serum is added to the microplate.
• Antibody in the serum will bind to the antigen.
• The well in the plate is washed with an enzyme tagged
antihuman antibody which binds to the patient
antibody.
• A substrate for the enzyme is added and a color
reaction occurs .
Diagnostic Tests- ELISA
• Microplate
Antibody/antigen/
Enzyme complex
Molecular Diagnostic Tests
• Nucleic Acid Hybridization
• To identify a bacteria or virus, a
species specific nucleic acid
probe is needed.
• Probes are a single strand of DNA
with a sequence unique and
complimentary to the gene of
interest.
• If a clinical specimen contains the
microorganism of interest, the
probe will bind to the
microorganism’s gene DNA
sequence.
• The double stranded DNA is
detected because the probe is
labeled with a radioactive,
fluorescent, or enzyme tag.
Molecular Diagnostic Tests
• PCR
• There are PCR tests available to extract
DNA or RNA from bacteria or viruses.
• The PCR method uses species specific
primers for targeted DNA or cDNA.
• The DNA is then amplified.
• Detection of the gene sequence can be
done by gel electrophoresis.
• An alternative to electrophoresis is the
use of PCR machines with precision
optics monitors.
• The primer has a fluorescent label and
the monitor plots the uptake of the
primer. If the primer has been used, this
indicates the presence of the
microorganism.
Epidemiology
• In investigating an outbreak, speed is essential, but getting the right
answer is essential, too. To satisfy both requirements, epidemiologists
approach investigations systematically, using the following 10 steps:
• Prepare for field work
• Establish the existence of an outbreak
• Verify the diagnosis
• Define and identify cases
• Describe and orient the data in terms of time, place, and person
• Develop hypotheses
• Evaluate hypotheses
• Refine hypotheses and carry out additional studies
• Implement control and prevention measures
• Communicate findings
• The steps are presented here in conceptual order. In practice, however,
several may be done at the same time, or they may be done in a different
order. For example, control measures should be implemented as soon as
the source and mode of transmission are known, which may be early or
late in any particular outbreak investigation.
Epidemiology
• Step 1: Prepare for Field Work
• Before leaving for the field:
• Research the disease and gather the supplies/
equipment needed
• Make necessary administrative and personal
arrangements for such things as travel.
• Consult with all parties to determine your role in
the investigation and who your local contacts will
be.
Epidemiology
• Step 2: Establish the Existence of an Outbreak
• Verify that a suspected outbreak is indeed a real
outbreak.
• Some of the cases will be associated with a true outbreak
with a common cause, some will be unrelated cases of the
same disease, and others will turn out to be unrelated
cases of similar but unrelated diseases.
• Before you can decide whether an outbreak exists (i.e.,
whether the observed number of cases exceeds the
expected number), you must first determine the expected
number of cases for the area in the given time frame.
Epidemiology
Epidemiology
Dx
• Step 3: Verify the Diagnosis
• In addition to verifying the existence of an outbreak
early in the investigation, you must also identify as
accurately as possible the specific nature of the
disease.
• Goals in verifying the diagnosis are two-fold.
- First, ensure that the problem has been properly
diagnosed—that it really is what it has been reported
to be.
- Second, for outbreaks involving infectious or toxicchemical agents, be certain that the increase in
diagnosed cases is not the result of a mistake in the
laboratory.
Epidemiology
• Step 4: Define and Identify Cases
• Establish a case definition. Your next task as an
investigator is to establish a case definition, or a
standard set of criteria for deciding whether, in
this investigation, a person should be classified
as having the disease or health condition under
study. A case definition usually includes four
components:
• clinical information about the disease,
• characteristics about the people who are
affected,
• information about the location or place, and
• a specification of time during which the outbreak
occurred.
Epidemiology
• Step 5: Describe and Orient the Data in Terms of Time, Place,
and Person
• After data collection, characterize an outbreak by time, place,
and person. This step may be performed several times during
the course of an outbreak. Characterizing an outbreak by these
variables is called descriptive epidemiology,
• This step is critical
- First, by becoming familiar with the data, you can learn what
information is reliable and what is not.
- Second, you provide a comprehensive description of an
outbreak by showing its trend over time, its geographic extent
(place), and the populations (people) affected by the disease.
This description lets you begin to assess the outbreak in light of
what is known about the disease and to develop causal
hypotheses.
Epidemiology (descriptive)
Epidemiology
• Step 6: Develop Hypotheses
• In real life, we begin to generate hypotheses to
explain why and how the outbreak occurred
when we first learn about the problem. But at
this point in an investigation, after you have
interviewed some affected people, spoken with
other health officials in the community, and
characterized the outbreak by time, place, and
person, your hypotheses will be sharpened and
more accurately focused.
• The hypotheses should address the source of
the agent, the mode (vehicle or vector) of
transmission, and the exposures that caused the
disease. Also, the hypotheses should be
proposed in a way that can be tested.
Epidemiology
• Step 7: Evaluate Hypotheses
• The next step is to evaluate the credibility of
your hypotheses. There are two approaches
you can use, depending on the nature of your
data: 1) comparison of the hypotheses with
the established facts and 2) analytic
epidemiology, which allows you to test your
hypotheses with cohort and case control
studies.
Epidemiology (cohort study)
Epidemiology
Step 8: Refine Hypotheses and Carry Out Additional Studies
•
• Additional epidemiological studies
When analytic epidemiological studies do not confirm your
hypotheses, you need to reconsider your hypotheses and look for
new vehicles or modes of transmission. This is the time to meet
with case-patients to look for common links and to visit their homes
to look at the products on their shelves.
• Also, confirmation from laboratory findings can be valuable.
Epidemiology
Step 9: Implementing Control and Prevention
Measures
• Even though implementing control and
prevention measures is listed as Step 9, in a real
investigation you should do this as soon as
possible.
• Control measures, which can be implemented
early if you know the source of an outbreak,
should be aimed at specific links in the chain of
infection, the agent, the source, or the reservoir.
Epidemiology
• Step 10: Communicate Findings
• Your final task in an investigation is to
communicate your findings to others who
need to know. This communication usually
takes two forms: 1) an oral briefing for local
health authorities and 2) a written report
Epidemiology
• SARS – The True Story
http://www.youtube.com/watch?v=MXPaee0
uEQM
• Case study: SARS
Lesson 4
• Origin of SARs and evolution of the virus
• Work in groups of 4. Read powerpoint and
web articles about origin of SARS virus and
viral evolution.
• Discuss and respond to questions.
• Write a short essay explaining how natural
selection occurred with the SARS virus.
Origin of SARS & Evolution
• Visit the following websites for the origin of
SARS:
• http://www.abc.net.au/science/features/sars/
default.htm
• http://learn.genetics.utah.edu/archive/sars/in
dex.html
Origin of SARS and Evolution
• Visit the following websites for the evolution of SARS:
• http://www.smartplanet.com/blog/sciencescope/study-shows-how-swiftly-infectious-virusesevolve/12136
• http://www.scientificamerican.com/article.cfm?id=sars
-evolution-traced
• http://learn.genetics.utah.edu/archive/sars/index.html
Identification of SARS virus
• 6 weeks after the outbreak of SARS, CDC
identified the SARS virus as a coronavirus via
electron microscopy.
• http://www.smithsonianmag.com/sciencenature/Stopping_a_Scourge.html
• This is what they saw:
Identification of SARS virus
• Coronavirus
• Are single stranded RNA viruses
• Replicate in the cytoplasm of the
host cell.
• Spherical 60- 220 nm in size.
• Contain club shaped
glycoproteins on their surfaces.
The virus looks like it has a crown.
• Largest genome of any RNA
viruses; 29,700 base pairs.
Identification of SARS virus
• Replication
• The plus strand RNA enters the
cytoplasm.
• Only RNA polymerase is
translated directly from the
virus genome to protein.
• RNA polymerase makes a
negative RNA strand.
• Negative RNA strand is a
template to make monocistronic
(only codons for protein) m RNA
that is used in translation.
Identification of SARS virus
• The second step in identification
of the virus was to discover the
DNA sequence of the virus.
• Three months after the
outbreak, Canada’s Michael
Smith Genome Sciences Center
in British Columbia sequenced
the SARS coronavirus.
• The DNA sequence is located in
GenBank.
• http://www.msfhr.org/news/feat
ures/2009/03/speed_demons
Identification of SARS virus
• Bioinformatics
• DNA isolates were taken from SARS
virus and compared to DNA isolates
from other coronaviruses and other
strains of SARS viruses.
• By comparing SNP (single
nucleotide polymorphism) among
the DNA isolates, researchers were
able to classify the virus and create
a phylogenetic tree.
• Researchers also discovered that
four proteins were responsible for
pathogenesis of SARS: spike (S)
protein; small envelope (E) protein;
membrane (M) protein; and
nucleocaspid (N) protein.
Patient Diagnostics -SARS
• The DNA sequencing and research led to two
frequently used tests to help diagnose SARS in
patients.
1. RTPCR – Real Time Reverse Transcriptase
PCR
2. ELISA – Enzyme linked immunoassay
Patient Diagnostics
•
•
•
•
•
RTPCR
Enables researchers to quantify amplification reactions in real time.
A specialized thermo cycler with a laser scan beams light through the PCR tube.
The PCR product is labeled with a fluorescent tag.
The amount of fluorescent light produced after each cycle is printed on a computer
readout.
• This allows for quantification of the number of PCR products produced after each
cycle.
• For diagnosis of SARs, patient tissues and body fluids can be used directly. The
primers used in the test are specific for cDNA made from the viral genome.
• http://www.youtube.com/watch?v=kvQWKcMdyS4
Patient Diagnosis
• ELISA
• The SARS antigen is bound to a
microplate.
• The patient’s blood serum with SARS
antibodies is introduced.
• The patient SARs antibody binds to the
SARS antigen.
• A second antibody with an enzyme
attached combines with the SARS
antibody/antigen complex.
• When a substrate is added,t he well in
the microplate turns color with a
positive reaction .
• http://highered.mcgrawhill.com/sites/0072556781/student_vie
w0/chapter33/animation_quiz_1.html.
Patient Diagnostics
• ViroChip
• A DNA microarray test system called ViroChip enables doctors to screen
for the type of virus present in a patient, if they do not know the virus
type.
• A ViroChip has 22,000 DNA sequences on it and identifies a variety of
different viruses.
• http://www.nytimes.com/2008/10/07/health/research/07conv.html
Lesson 5
• Immunology
• Work in groups of 4.
• Read powerpoint, discuss, and respond to
questions.
• Complete chart of immune responses.
• Whole class discussion of responses.
• Write a 5 minute commercial or skit about the
immune system.
• Present skit or commercial.
Immunology
• Two types of immunity
• Innate or Non-specific Immunity
• Adaptive or Acquired Immunity
Immunology
• 3 Lines of Defense in
immunity
• Barriers at body surfaces
(innate)
1. Intact skin and mucous
membranes
2. Infection fighting tears
and saliva.
3. Normal bacterial flora
outcompete pathogens.
4. Flushing effects of tears,
urination, diarrhea.
Immunology
• 3 Lines of Defense
• Non-specific Responses (Innate)
1. Inflammation
a. Fast acting white blood cells;
neutrophils, basophils,
eosinophils.
b. Macrophages
c. Complement proteins and
other infection fighting
substances.
2. Organs with phagocytic functions
i.e. lymph nodes.
Immunology
• 3 Lines of Defense
• Immune Responses
(Adaptive or Specific)
• T cells and B cells
• Communication
signals and chemical
weapons ( antibodies,
complement proteins
etc.)
Innate or Non –Specific Immunity
• Innate Immunity – Non specific
responses
• Innate immunity is a non specific
attack against any cell or particle
that is not self.
1. Antimicrobial agents
2. Phagocytic cells
3. Nonphagocytic cells
4. Natural killer cells 
5. Inflammation and Fever
Innate or Non-Specific Immunity
• Innate - Antimicrobial agents
• Antimicrobial agents are chemicals or molecules
that act to deter or destroy microorganisms.
Some of them act in conjunction with physical
barriers.
There are 3 types:
1. Interferon
2. Interleukins
3. Complement
Innate or Non-specific Immunity
• Interferon
• Interferons are a large group of
proteins that acts as signals both
during innate and adaptive
immune responses.
• Interferon is produced early in
viral infections by a cell.
• The interferon will not keep the
cell from viral infection but it is
released and warns other cells to
synthesize antiviral cell surface
proteins.
• http://www.youtube.com/watch
?v=3qFu6Fv4cJk&feature=relate
d
Innate or Non-specific Immunity
• Interleukins
• Interleukins are another
class of proteins which
are produced by cells of
the immune system.
• Tumor necrosis factor
(TNF) , a type of
interleukin, stimulates
cells to create an
inflammatory response.
• TNF cells can also kill
tumor cells.
Innate or Non-specific Immumity
• Complement: a family of 20 different proteins.
• Found in blood serum and protect the body
from infection.
• Works together with other components of the
innate and adaptive immune systems.
• Generally, complement is inactive.
• In the presence of an antigen, complement
becomes activated.
Innate or Non-specific Immunity
• Complement
• Complement is activated in 4 general and non
specific ways.:
• Some complement proteins coat the surface
of a pathogen so phagocytes can engulf them.
• Other complement proteins lyse the cell wall
of microorganisms
• Other complement proteins trigger the
release of histamine which increases
inflammation by dilating blood vessels and
increasing capillary permeability.
• Some complement proteins attract
lymphocytes.
• http://highered.mcgrawhill.com/sites/0072556781/student_view0/ch
apter31/animation_quiz_1.html
Innate or Non-specific Immunity
• Innate – Phagocytic Cells
• Sometimes an infectious agent
avoids physical barriers and
antimicrobial agents in the body.
• A 3rd line of defense is available.
• Phagocytic cells engulf
microorganisms in digestive
vacuoles and break down cells.
• Phagocytic cells contain many
enzymes: lysozyme to breakdown
peptidoglycan, proteases to break
down proteins, nucleases to break
down DNA and RNA, and lipases to
break down lipids.
Innate or Non-specific Immunity
• Phagocytic Cells
• There are 2 types of phagocytic cells:
1. Stationary phagocytes – reside along blood
vessel walls and in connective tissue
2. Wandering phagocytes – circulate in the
blood.
• Both types are made in the bone marrow
Innate or Non-specific Immunity
• Stationary phagocytes
• Macrophages are large phagocytic cells.
• Made in the bone marrow, they circulate
in the blood for a few days and are called
monocytes at this stage.
• Monocytes are released into connective
tissue and are now referred to as
macrophages.
• Macrophages are scavenger cells. They
engulf:
1. Microorganisms
2. Dead body cells
3. Cancer cells
4. Cells infected with viruses.
• The life span of a macrophage is from a
few months to many years.
http://www.youtube.com/watch?v=
m6qJ69wcSnc
Innate or Non-specific Immunity
• Wandering Phagocytes
• Wandering phagocytes are white
blood cells called monocytes and
neutrophils.
• There are 4,000-6,000
neutrophils/mm3 of blood. They
account for 65% of all white cells.
• In a bacterial infection, neutrophil
numbers can double.
• Neutrophils are mobile. They can
squeeze through capillaries and
into cells; they can enter the spinal
column to fight meningitis.
• http://hippocampusbiology.blogsp
ot.com/2009/03/bacteria-can-runbut-they-cant-hide.html
Innate or Non-Specific Immunity
• Innate – Nonphagocytic Cells
• Eosinophils – White blood cells that secrete enzymes
that attack parasitic worms; reside in blood.
• Basophils - White blood cells that contain heparin
(stops blood from clotting) and histamine (vasodilator
which promotes blood flow to tissues). Play a role in
inflammation and allgergies. Reside in blood.
• Mast Cell - Cells residing in many tissues that contain
heparin and histamine. Look like basophils but come
from different cell line. Important in inflammation.
Innate or Non Specific Immunity
Eosinophil
Basophil 
Mast Cell
Innate or Non-specific Immunity
• Innate – Natural Killer Cells
• Are not phagocytic.
• Are a white blood cell called a
lymphocytes
• Attach to cell surfaces and produce
enzymes that destroy antibody
covered cells that have been
infected with microorganisms or
viruses.
• Also able to destroy cancer cells.
• http://www.youtube.com/watch?v
=HNP1EAYLhOs
Innate or Non-specific Immunity
• Innate – Inflammation
• Inflammatory response is a major component of the
innate immune system.
• In inflammation:
1. When tissue is injured or microorganisms enter the
tissue, mast cells release chemicals called histamine.
Innate or Non-specific Immunity
• Inflammation
2. The chemicals spark the mobilization of various defenses.
a. Histamine induces blood vessels to dilate and increases
blood flow to the injured tissue.
b. Blood plasma leaks out of the blood vessels to the affected
tissues.
c. Phagocytic cells squeeze out of the blood vessels and
migrate to the tissue.
d. Increased blood flow, fluid, and cells produce redness,
heat, and swelling of tissues.
Innate of Non-specific Immunity
• Inflammation
3. The major results of inflammation is
to disinfect and clean injured tissue.
a. Phagocytic cells engulf bacteria and
body cells killed by them.
b. Many phagocytic cells die in this
process and they are engulfed and
digested.
c. Pus that accumulates at the injury site
consists of dead cells and fluid from
leaking capillaries.
Innate or Non-specific Immunity
• Inflammation
• Inflammation helps prevent
the spread of infection to
surrounding tissues.
• Clotting factors and platelets
pass into the tissues from the
blood and form local clots to
seal off the infected region.
• The damaged tissue begins to
repair.
http://www.sumanasinc.com/
webcontent/animations/conte
nt/inflammatory.html
Innate or Non-specific Immunity
• Innate- Fever
• During some infections, fever
occurs.
• Fever is induced by toxins released
by microorganisms.
• The increase in body temperature:
1. Kills some microorganisms.
2. Increases inflammation.
3. Stimulates phagocytic activity.
4. Stimulates adaptive (acquired)
immune response.
5. Reduces iron concentration in
blood and limits amount of iron
available to microorganisms.
Adaptive or Acquired Immunity
• Adaptive immunity is a complex set of interactions that
is highly specific against one type of antigen.
• Whereas innate immunity reacts to a variety of
pathogens, adaptive immunity must be primed by the
presence of an antigen.
• Adaptive immunity either attacks a specific antigenic
invader directly or it produces antibodies.
• There are two types of adaptive immunity:
1. Cell mediated immunity
2. Humoral immunity
Adaptive or Acquire Immunity
• Cell mediated immunity
involves a type of
lymphocyte called a T
(thymus) cell. T cells work
against infections caused by
fungus and protozoans.
Also, they are important in
eliminating cancer cells.
• Humoral immunity involves
a type of lymphocyte called
a B cell. B cells protect
against viruses and bacteria
in body fluids by producing
antibodies.
Adaptive or Acquired Immunity
• Both T cells and B cells
originate from stem cells in
the bone marrow.
• B cells continue to mature in
the bone marrow.
• T cells are carried from the
bone marrow to the thymus
gland to become specialized.
• Both T cells and B cells have
the ability to recognize self
from antigen.
Adaptive or Acquired Immunity
• Cell Mediated Immunity
• T cells after maturation are
moved to the lymphatic
system.
• T cells are primarily involved
in attacking cells directly.
• While T cells are maturing,
they develop the ability to
recognize specific antigens
(Non-self)
• For T cells to go into action,
they need the antigen
presented to them.
Adaptive or Acquire Immunity
• Cell mediated immunity
• All cells have surface
glycoproteins call the Major
Histocompatibilty Complex
(MHC).
• In humans, the MHC is called
HLA (human leukocyte antigen).
• These classes of molecules
mark our cells as self.
• Invading cells have an MHC and
this marks them as foreign.
Adaptive or Acquire Immunity
• Cell mediated immunity
• Cells like macrophages recognize
foreign (MHC) cells and ingest them.
• Macrophages(or other cells) then
display antigenic fragments from the
microorganism on their cell surfaces.
• Macrophages displaying antigens
are called antigen presenting cells
(APC).
• T cells bind to the
macrophage/antigen complex and
this activates the T cell.
• T cells will then proliferate and carry
out their functions.
Adaptive or Acquire Immunity
• Cell mediated immunity
• There are 2 types of T cells:
1. CD8 or cytotoxic T cells
2. CD4 or helper T cells
Adaptive or Acquire Immunity
• Cell mediated immunity
• CD8 cells
• CD8 cells respond to foreign
antigens on the cell’s surface by
binding to the antigenic MHC on
the invading cells and directly
killing them.
• CD8 cells release perforin, a
protein that creates pores on
the invading cells membrane.
Water and ions flow into the
cells and the cell lyses.
• Cancer cells, foreign cells from a
transplant or graft, pathogen
infected cells, and virus infected
cells are targeted by CD8 cells.
http://www.theimmunology.com/anima
tions/Cytotoxic.T.Cell.htm
Adaptive or Acquired Immunity
Adaptive or Acquired Immunity
• Cell mediated immunity
• CD4 cells
• CD4 cells that have been activated by an APC secrete
cytokines, a protein that stimulates other lymphocytes.
• If B cells have contacted an antigen, the signal from the CD4
cell differentiates the B cell into an antibody producing cell.
• CD4 cells also play a role in stimulating CD8 cells to
proliferate.
• http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapter22/animat
ion__t-cell_dependent_antigens__quiz_2_.html
Adaptive or Acquired Immunity
• Humoral Immunity
• B cells are involved in humoral immunity.
• B cells produce antibody. The antibody
produced by a B cell is specific for a particular
antigen.
• There are two types of B cells:
1. Plasma Cells
2. Memory Cells
Adaptive or Acquired Immunity
• Humoral immunity
• Plasma Cells
• A plasma cell encounters an
antigen and secretes a
specific antibody.
• Plasma cells are activated
when they encounter an
antigen and are stimulated
by helper T cells.
• Plasma cells can produce
more than 10 million
antibodies in an hour.
Adaptive or Acquired Immunity
• Humoral immunity
• Memory Cells
• Not all activated B cells become
plasma cells.
• Some become memory cells and
produce small amounts of
antibody after an infection has
been eliminated.
• If the same microorganism is
encountered again, the memory
cells change to plasma cells and
begin producing antibody.
• This enables the immune system
to attack rapidly and aggressively
if there is re-infection.
http://highered.mcgrawhill.com/sites/0072495855/student_v
iew0/chapter24/animation__the_im
mune_response.html
Adaptive or Acquire Immunity
• Antibodies
1. Antibody structure and function
2. Disposal of antibody/antigen complex.
Adaptive or Acquired Immunity
• Antibody structure and function
• Antigens that elicit an antibody
response are typically a protein or
polysaccharide surface component
of microbes.
• The antibody does not bind to the
total antigen.
• A small accessible portion of
antigen called an epitope or
antigenic determinant is available
for binding to the antibody.
• A single antigen has several
epitopes and each epitope binds
to a different antibody.
Adaptive or Acquired Immunity
• Antibody structure and
function.
• Antibodies are globular serum
proteins called
immunoglobulins.
• There are two antigen binding
sites for specific epitopes on an
antibody.
• Each antibody consists of 4
polypeptide chains. 2 identical
heavy chains and 2 identical
light chains.
Adaptive or Acquired Immunity
• Antibody Structure and
Function
• At the 2 tips of the antibody
are variable regions (on light
and heavy chains).
• The amino acid sequence
varies from antibody to
antibody.
• The variable region gives the
antibody specificity for an
antigen.
• The binding of the epitope
and the binding site is
similar to an enzyme
substrate reaction.
Adaptive or Acquired Immunity
• Antibody structure and
function
• The tail of the antibody is
formed by the constant
region.
• The constant region is
responsible for distribution of
the antibody within the body
and for mechanisms that
mediate the disposal of the
antibody/antigen complex.
• There are 5 types of heavy
chain constant regions: IgA,
IgG, IgM, IgD, and IgE.
Adaptive or Acquire Immunity
• Disposal antibody/antigen complex
• The binding of antibody to antigen creates
complexes that must be disposed.
• Three types of disposal
1. Neutralization/Opsonization
2. Agglutination/ Precipitation
3. Complement fixation
Adaptive or Acquire Immunity
• Disposal antibody/antigen complex
• Neutralization/Opsonization
• In neutralization, the antibody binds to the
antigen.
• The microbe covered in antibodies is
phagocytized by macrophages.
• Opsonization is similar to neutralization.
Compounds called opsins bind to
antibody/antigen complexes and this enhances
the ability of the macrophage to phagocytize the
microorganism
Adaptive or Acquired Immunity
• Disposal antibody/antigen complex
• Agglutination
• Agglutination is possible because antibodies have 2 antigen
binding sites.
• One site can attach to one bacteria and the second site can
attach to a second bacteria.
• When thousands of antibodies behave in this way, a
clumping of the microorganisms occurs.
• Precipitation is similar to agglutination as clumping occurs.
• In precipitation, the antigens cross link and form a
precipitate.
• Both processes are followed by macrophage phagocytosis.
Adaptive or Acquired Immunity
• Disposal antibody/antigen complex
• Complement Fixation
• Antibody/antigen complexes activate
a complement cascade.
• Complement consists of 20 proteins
and in the cascade one type of
complement triggers the production
of the next type in a series of
reactions.
• Completion of the complement
cascade results in lysis of viruses and
pathogenic cells or opsonization.
• http://highered.mcgrawhill.com/sites/0072556781/student_vi
ew0/chapter31/animation_quiz_1.ht
ml
Lesson 6
•
•
•
•
ELISA Lab – SARS virus
Conduct ELISA test.
Write lab report
Refer to your handouts
Lesson 6
• Vaccines
• Read article: How do vaccines work?
• Discussion: How is this related to discussion of
immune system
• Lecture- Types of vaccines (biotechnology)
• Whole class review with questions of vaccine types.
• Video: Mothers who do not vaccinate their children.
• Read and review article on causal relationships
between vaccines and adverse effects.
• Discussion: Should childhood vaccination be
mandatory?
Lesson 5
• Vaccines
Vaccines
• How do vaccines work?
• http://www.healthychildren.org/English/safetyprevention/immunizations/pages/How-doVaccinesWork.aspx?nfstatus=401&nftoken=000000000000-0000-0000000000000000&nfstatusdescription=ERROR%3a+
No+local+token
• http://www.historyofvaccines.org/content/howvaccines-work
Vaccines
• Vaccination has proven effective
against fighting diseases caused
by microorganisms.
• Infectious disease is one of the
major causes of death
worldwide. 60% of children
worldwide under the age of 4 die
from infectious disease.
• The world’s first vaccine was
made by Edward Jenner in 1796.
He discovered that the live
cowpox virus could be used to
immunize patients against
smallpox.
Vaccines
• Vaccines
• Vaccines are parts of a pathogen or
whole organisms that are given to
humans or animals by mouth or by
injection to stimulate the immune
system.
• When people or animals are
vaccinated, the immune system
recognizes the vaccine as antigen
and produces antibodies and
memory B cells.
Vaccines
• Vaccines
• Four major strategies
are used to make
vaccines:
1. Subunit vaccines
2. Attenuated vaccines
3. Inactivated (killed)
vaccines
4. DNA vaccines
Vaccines
• Vaccines
• Subunit vaccines
• Subunit vaccines are made by
injecting portions of viral or bacterial
structures, usually proteins or lipids
from the microbe, to which the
immune system responds.
• EX: Vaccines for hepatitis B, anthrax,
tetanus, and meningococcal disease.
• http://library.thinkquest.org/20994/
data/task8-2.html
Vaccines
• Vaccines
• Attenuated vaccines
• Attenuated vaccines involve using
live bacteria or viruses that have
been weakened (attenuated) by
aging or alteration of growth
conditions.
• Attenuation prevents replication
after the vaccine is introduced into
the recipient.
• EX: Vaccines for MMR,
tuberculosis, cholera, Saban polio,
and chickenpox.
Vaccines
• Vaccines
• Inactivated vaccines
• The pathogen is killed and
the dead microorganism is
used for the vaccine.
• EX. Vaccines for rabies,
influenza, DPT, and Salk
polio.
Vaccines
• Vaccines
• DNA Vaccines
• DNA vaccines have
demonstrated that injecting
small pieces of DNA from a
microbe create an antibody
response.
• DNA vaccines are composed of
bacterial plasmids. Expression
plasmids used in DNA-based
vaccination normally contain
two units: the antigen
expression unit, followed by
antigen-encoding and
polyadenylation sequences and
the production unit that is
composed of bacterial
sequences necessary for plamid
amplification and selection
• DNA vaccines for HIV and
malaria are in clinical trials.
Vaccines
Vaccines
• Vaccines
• http://www.pbs.org/wgbh/pages/frontline/te
ach/vaccine/
• Pros and cons of vaccination
• http://www.hrsa.gov/vaccinecompensation/a
dverseeffects.pdf
• Causality vaccines