11.1 | Antibody
Production &
Vaccination
What happen is the immune system has
never encountered the antigen before?
© David Faure, InThinking http://www.thinkib.net/biology
A macrophage is a type of phagocyte.
Pathogens are engulfed by macrophages.
The macrophage displays the antigens from the surface of
the pathogen on the outside of the macrophage membrane
helper T-cells bind to antigen (on macrophage)
and helper T-cells are activated
● Activate B-cells
Memory cells
Activated helper T-cells
●
which clone
Plasma
cells
plasma cells produce specific antibodies to the antigen
Memory cells give immunity
Vaccination
Vaccinations induce long-term immunity to specific pathogenic
infections by stimulating the production of memory cells
■ A vaccine is a weakened or attenuated form of the
pathogen that contains antigens but is incapable of
triggering disease
■ The antigenic determinants in a vaccine may be conjugated
to an adjuvant, which functions to boost the immune
response
■ The body responds to an injected vaccine by initiating a
primary immune response, which results in memory cells
being made
■ When exposed to the actual pathogen, the memory cells
trigger a more potent secondary immune response
■ As a consequence of this more potent immune response,
disease symptoms do not develop (individual is immune to
pathogen)
The length of time a person is immune to infection following
a vaccination depends on how long the memory cells survive
for
■ Memory cells may not survive a lifetime and individuals
may subsequently require a booster shot to maintain
immunity
Task
Create a story board showing how vaccines work
Herd Immunity
Vaccinations programmes are implemented to reduce the
outbreak of particular infectious diseases within populations
■ An epidemic is a substantially increased occurrence of a
particular infection within a given region
■ A pandemic is an epidemic that has spread across a large
geographical area (like a continent)
Vaccination confers immunity to vaccinated individuals but
also indirectly protects non-vaccinated individuals via herd
immunity
■ Herd immunity is when individuals who are not immune to a
pathogen are protected from exposure by the large amounts
of immune individuals within the community
Questions
1.What does the video claim to be the cause of the
recent increase in measles cases in the USA?
2.What evidence is presented to support this claim?
Smallpox
Smallpox was the first infectious disease of humans to have
been eradicated via vaccination
■ When a disease stops circulating in a region it is
considered eliminated – if it is eliminated worldwide, it
is considered eradicated
Smallpox was targeted for eradication in 1967 by the World
Health Organisation (WHO), via a global vaccination programme
■ The last known case of smallpox in a civilian was
registered in 1977 and it was officially declared
eradicated by WHO in 1980
The eradication of smallpox by vaccination was successful for
a number of reasons:
■ Smallpox was easily identifiable due to overt clinical
symptoms, which helped to limit potential transmission
■ Transmission only occurred via direct contact and there
were no animal vectors or reservoirs to sustain the
infectious agent
■ The infection period was short lived (3 – 4 weeks) and
the virus was stable and didn’t mutate into alternate
strains
■ There was global cooperation and immunity was long-term
so repeated booster shots were unnecessary
Vaccination programmes have lead to a reduction in the
incidence of infectious diseases in a number of regions
■ Different nations will implement different vaccination
practices depending on the regional pathogenic threats
The World Health Organisation keeps a record of disease
incidence and immunisation schedules in different countries
■ These records are updated yearly and can be accessed at
the following website: WHO Data and Statistics
Epidemiology is the study of the patterns, causes and effects
of health and disease conditions in a defined population
■ It can be used to compare the incidence of a disease over
time (prior and following vaccination programme
implementation)
■ It can be used to compare the incidence of a disease in
different regions (both with and without vaccination
programmes)
Vaccination Data
The following resources can be used to generate data tables
and graphs relating to national vaccination programmes:
■ Reported Disease Incidence Time Series
(Excel file)
■ Year of Introduction of Selected Vaccine
(Excel file)
When analysing trends associated with this data it is
important to remember the following caveats:
■ Populations have increased year on year, which would be
likely to increase the risk of potential outbreaks
■ Improvements to health care services, public sanitation
and medical breakthroughs will also influence disease
rates
■ Different regions may experience different levels of
exposure to particular infections (due to climate and
vector presence)
New lesson
Monoclonal antibodies
Monoclonal antibodies are antibodies artificially derived
from a single B cell clone (i.e. identical specific
antibodies)
■ An animal (typically a mouse) is injected with an antigen
and produces antigen-specific plasma cells
■ The plasma cells are removed and fused (hybridised) with
tumor cells capable of endless divisions (immortal cell
line)
■ The resulting hybridoma cell is capable of synthesising
large quantities of monoclonal antibody
Monoclonal antibodies can be used for both the therapeutic
treatment and clinical detection of disease
■ An example of therapeutic use involves the use of
antibodies in the treatment of rabies
■ An example of diagnostic use involves the use of
antibodies in the detection of pregnancy
Treatment Use
Monoclonal antibodies are commonly used to provide immune
protection for individuals who contract harmful diseases
■ Because the rabies virus can potentially be fatal,
injecting purified antibodies functions as an effective
emergency treatment
■ Monoclonal antibodies can be used to target cancer cells
that the body’s own immune cells fail to recognise as
harmful
Therapeutic monoclonal antibodies are named according to
the source organism from which the antibodies were derived
■ Mice antibodies ('-omab’) are easier to synthesise than
human antibodies but are less likely to be tolerated by
the patient
Diagnostic Use
Monoclonal antibodies can be used to test for pregnancy via
the presence of human chorionic gonadotrophin (hCG) in urine
■ hCG is a hormone produced by women during fetal
development and thus its presence in urine is indicative
of pregnancy
Pregnancy tests use a process called ELISA (enzyme-linked
immunosorbent assay) to identify a substance via a colour
change
■ Free monoclonal antibodies specific to hCG are conjugated
to an enzyme that changes the colour of a dye
■ A second set of monoclonal antibodies specific to hCG are
immobilised to the dye substrate
■ If hCG is present in urine, it will interact with both
sets of monoclonal antibody (forming an antibody
‘sandwich’)
■ When both sets of antibody are
bound to hCG, the enzyme is
brought into physical proximity
with the dye, changing its colour
■ A third set of monoclonal
antibodies will bind any
unattached enzyme-linked
antibodies, functioning as a
control