ARO Training & Consulting
Bloodborne Pathogens
Module 2: The Immune System
Page 8
Job Description: Chief of Operations – Immune System
Title:
Chief of operations
Homeland Security
Organization:
Immune system
Objectives:
To create a world-class program for homeland security that ensures
the pride, confidence and security of its citizens (body cells).
Duties and
responsibilities:
Command local, regional, national and global public safety and
defense programs.
Maintain resources to continuously improve the quality and
effectiveness of local, regional, national and global operations.
Develop and
stakeholders.
communicate
directly
and
openly
with
all
Establish and utilize appropriate Chain of Command to ensure
optimal performance of defense systems.
Develop creative approaches to ensure adequate supplies of new
recruits.
Develop and continuously update continuing educational training
and assess personnel to ensure ongoing competence.
Establish and regularly asses elite offensive and defensive
maneuver training programs in locations throughout the homeland.
Establish intelligence and communications agencies and bureaus
and oversee the effectiveness and appropriateness of their actions.
Qualifications
and
requirements:
Excellent leadership skills.
Proven ability to respond quickly and thoughtfully to situations that
threaten the safety of the homeland.
Proven ability to balance justice and compassion.
Extensive knowledge of global issues.
Multilingual requirements ( 3 languages).
Advanced degrees in strategic planning and strategic maneuvers.
ARO Training & Consulting
Bloodborne Pathogens
Module 2: The Immune System
Page 9
Advanced leadership, communication degree.
Proven ability to instill the principles of honor, justice, valor and
pride in serving the homeland.
Successful candidate must demonstrate in-depth knowledge of the
overall system, as well as partner organs and the importance of the
role of each in the successful operation of the overall system.
Successful candidate must be detail and process oriented.
Lines of
Communication:
Sophisticated global communication network
Excellent communication skills required.
Successful candidate must be an effective leader, motivating,
mentoring personnel.
Successful candidate must demonstrate ability to build strong lines
of communication with all stakeholders.
Proven ability to communicate effectively on the world stage.
Proven ability to remain calm, clear and alert in the most stressful
of situations.
Times needed Must be available to respond to all homeland safety concerns at the
and
expense of personal situations.
place of work:
Extensive travel required (transportation supplied).
Virtual home office.
Commitment
required:
Benefits:
The Chief of Operations must be committed to a long-term
relationship.
Honor and respect of nationalists and internationalists.
Frustrations:
Opportunity to motivate and mentor superiors, peers and
subordinates.
Possibility of burnout due to repeated stresses.
Constant bombardment of questions.
Possibility of misinterpretation through national and global relations.
ARO Training & Consulting
Bloodborne Pathogens
Module 2: The Immune System
Page 10
Immune response
One of the many functions of the body is to protect itself from invasion by foreign
substances such as viruses, bacteria, fungi, parasites, toxins and poisons. The
ability of the body to protect itself from disease-causing agents is known as
immunity. This protective role is performed by the immune system – a complex
system of specialized cells and organs including lymphoid tissues, immune cells,
and chemicals that manage immune functions. The various components of the
immune system act similarly to security devices used to protect your home – the
immune system contains physiological components that function as surveillance
cameras, burglar alarms and detectives with long memories.
“Self” and non-self”
Two key features of the human immune system are specificity and memory.
Specificity enables the body to distinguish “self” from “non-self”. “Self” refers to
anything that originated from within my body, while “non-self” refers to anything
that did not originate from within my body. Differentiation of self from non-self is
important for detection of invading microorganisms that may harm the body.
However, when organs or tissues are transplanted from one individual to
another, this ability works against us – transplanted tissue may be viewed as
“non-self” and be attacked as an invader. To prevent the tissue from being
rejected because it is different, testing is performed on the tissue donor and the
recipient to determine their compatability and optimize the chance that the
recipient’s immune system will consider the new tissue “self”, and accept it
without too much complaining. In addition, following a transplant surgery and
continuing, sometimes for life, immunosuppressants are administered.
Immunosuppressants suppress (hold back) immune response so that the body is
less sensitive to differences and, therefore, less likely to attack the foreign tissue
that has been transplanted. However, this lack of sensitivity may result in
immune system deficiency in recognizing invading microorganisms and may
result in an increased risk of infection. Life is all about balance!
In some individuals, for poorly understood reasons, the body begins to view its
own tissues as “non-self” and attacks them. This “self” attack or “auto” attack
may result in any of a number of debilitating and even life-threatening diseases –
rheumatoid arthritis is one of these. It is almost as if the immune system is
confused.
Diseases where the immune system attacks “self” are known as autoimmune
diseases. Memory enables the body to mount a stronger, more rapid immune
response when specific invaders are encountered following an initial infection or
exposure.
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Bloodborne Pathogens
Module 2: The Immune System
Page 11
Function of the immune system
The immune system performs three major functions:
- protects the body from pathogens, pollens, chemicals and other foreign
substances
- removes dead or damaged tissue and cells (i.e. old red blood cells, dying
and dead cells)
- recognizes and removes abnormal cells (i.e. cancer cells)
Anatomy of the Immune System
The immune system is comprised of lymphoid tissues and cells responsible for
assisting in body defence. The response potential of the immune system
exceeds the potential of our public safety system (military, intelligence and
communication agencies, law officers, emergency and fire response). The
thymus gland and the bone marrow are the two major lymphoid tissues
(headquarters) in the human body where immune system cells involved in
immune response form and mature.
Link to Normal Bone Marrow Cells:
http://www-medlib.med.utah.edu/WebPath/HEMEHTML/HEME153.html
In addition to the thymus gland and bone marrow, the spleen (purification and
recycling plant) and lymph nodes (check-points where blood and lymph fluid is
filtered) are also lymphoid tissues.
Link
to
immune
system
organs:
http://www.bio.davidson.edu/Courses/immunology/hyperhuman/HHH.html)
The spleen is the largest lymphoid organ in the body and contains immune cells
that monitor the blood for foreign invaders. Similar to a garbage collection center
or water purification plant, fluid entering the spleen contains debris, old and
abnormal cells, and microorganisms. The blood from old red blood cells is broken
down, and the iron and other substances is extracted and transported to the liver
for processing.
Lymph nodes are oval organs containing clusters of immune cells that act as a
filter to intercept pathogens entering the body through the lining of mucous
membranes or breaks in the skin. The lymph nodes prevent pathogen spread
throughout the body. Lymph nodes contain macrophages, lymphocytes and
dendritic cells, and the detection and communication capabilities are much more
sophisticated than airport security checkpoints or immigration and customs
checkpoints.
Macrophages ingest abnormal antigens, cellular debris, and microorganisms,
breaking them down and “presenting” the antigens to lymphocytes for
interrogation to determine whether the antigen should be detained for further
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Bloodborne Pathogens
Module 2: The Immune System
Page 12
questioning to determine its guilt or innocence. Similar to routine checkpoints on
a busy highway, some unidentified offenders may pass through undetected, but
most are removed from circulation and subjected to further questioning, citation
and/or arrest.
Lymphatic capillaries collect fluids that have been forced out into the spaces
between cells and tissues (interstitial spaces) with the pressure resulting from
each contraction of the left ventricle of the heart – sort of like the overflow from
major freeways or highways. Lymphatic capillaries carry lymph fluid to larger
lymphatic vessels that must also pass through the lymph nodes. Purified lymph
fluid then continues out through lymphatic vessels on the other side of the lymph
node to the next checkpoint en-route to the vena cava where the fluid re-enters
the blood stream.
Clusters of immune cells are also located throughout the skin, respiratory,
intestinal tract, urinary and reproductive tracts to intercept pathogens before they
enter the general circulation.
Link
to
immune
system
organs:
http://www.bio.davidson.edu/Courses/immunology/hyperhuman/HHH.html)
White blood cell production
All white blood cells descend from a type of cell known as a stem cell. Stem cells
originate in bone marrow and develop into one of several cell types – red blood
cells, leukocytes, and cells from which platelets are formed (megakaryocytes).
Link
to
cell
differentiation:
http://www.nucleusinc.com/medicalanimations.php?page_no=1&show_anim=myeloma.mov
Link
to
normal
bone
marrow
smear:
medlib.med.utah.edu/WebPath/HEMEHTML/HEME151.html
http://www-
Types of white blood cells
White blood cells (leukocytes) are the main cell type of the immune system;
therefore, they are referred to as immune cells. There are six major types of
leukocytes, distinguishable in stained tissue samples and blood samples by their
morphological characteristics – cell shape and size, nucleus shape and size,
cytoplasm characteristics, and characteristics of the cell border:
 eosinophils
 basophils
 neutrophils
 monocytes
 lymphocytes
 dendritic cells
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Bloodborne Pathogens
Module 2: The Immune System
Page 13
With the exception of dendritic cells, all of the immune cells listed above are
leukocytes and are found normally in blood circulating throughout the body.
Leukocytes use the circulatory system as a transportation route from lymphoid
tissues where they are formed to tissues where they are required to help fight
infection and other foreign invaders. The circulatory system involves a
transportation system where arteries lead out to the suburbs (tissues) and veins
run from the suburbs back to the city center (heart). In a normal healthy
individual, a certain number of leukocytes are normally expected in a specific
volume of blood.
Cells fall into one of two categories – those containing granules in the cytoplasm
(granular; granulocytes) and those that are agranulocytic (do not contain
granules).
Granulocytes
Eosinophils
Eosinophils are normally found in relatively low numbers in circulating blood (13% of all leukocytes), and are distinguished from other leukocytes on stained
preparations by the presence of bright pink-stained granules in their cytoplasm.
Eosinophils fight parasites and are involved in allergic reactions.
The life span of eosinophils in the blood is approximately 6-12 hours. Because of
their role in defending against parasitic infection, most functioning eosinophils are
found in the digestive tract, lungs, connective tissue of the skin, as well as urinary
and genital epithelium.
Eosinophils are classified as cytotoxic cells, because they release substances
that damage or kill pathogens. The main function of eosinophils is defence
against parasitic infections caused by helminths (worms); however, they also
participate in allergic reactions by releasing toxic enzymes and other substances
that contribute to inflammation and tissue damage.
Link
to
Eosinophil
image:
medlib.med.utah.edu/WebPath/HEMEHTML/HEME004.html
http://www-
Basophils
Basophils are produced in the bone marrow, and are found rarely in the
circulating blood (3-5% of total granulocytes in circulation) and are distinguished
from other leukocytes on stained preparations by the presence of large, dark
violet blue granules in their cytoplasm. Basophils are similar to mast cells, which
are found in connective tissue of the skin, lungs, and gastrointestinal tract.
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Bloodborne Pathogens
Module 2: The Immune System
Page 14
The granules of mast cells and basophils contain histamine, heparin, cytokines,
and other chemicals involved in allergic and immune responses – when granules
of these cells release their contents (degranulate), these chemicals are released.
The main function of basophils is defence against fleas, lice and ticks - basophils
act against antigens in the feces of these little critters, while mast cells are
involved in the immune response against pathogens that are inhaled, ingested,
or enter the body through breaks in the skin.
Link
to
Basophil
image:
medlib.med.utah.edu/WebPath/HEMEHTML/HEME005.html
http://www-
Link to Flea/tick response - http://www.cellsalive.com/mite1.htm
Neutrophils
Neutrophils are produced in the bone marrow and comprise 50-70% of the total
population of leukocytes normally present in the circulating blood. Neutrophils are
distinguished from other leukocytes in a stained preparation by the presence of a
segmented nucleus (polymorphonuclear) of three to five lobes connected by thin
strands of nuclear material. Because of the characteristic nuclear presentation,
neutrophils are also known as polymorphonuclear leukocytes. Neutrophils have a
life span of only one to two days.
Link
to
Neutrophil
image:
medlib.med.utah.edu/WebPath/HEMEHTML/HEME002.html
http://www-
The main function of neutrophils is neutralization of bacteria and viruses.
Neutrophils ingest and kill bacteria by a process known as phagocytosis. Surface
molecules on the pathogen bind directly to receptors on the phagocyte
membrane. The phagocyte receptors close around the invader as it continues to
bind to the pathogen surface molecules. The cell cytoskeleton pushes the cell
membrane around the pathogen forming a vesicle known as a phagosome. The
phagosome pinches off from the cell membrane and moves into the cytoplasm of
the cell, where it fuses with a storage vesicle, known as a lysosome. Enzymes
within the lysosome digest or break down the bacteria or particles.
Link to Cells Alive Phagocytosis: http://www.cellsalive.com/mac.htm
Link to Phagocytosis: http://www.bio.davidson.edu/misc/movies/Phago.mov
Animation
2.1
–
Phagocytosis
or
Link
to
Phagocytosis:
http://www.sp.uconn.edu/~terry/Common/phago053.html
Neutrophils belong to the category of leukocytes known as granulocytes,
because they contain inclusions in their cytoplasm that give them a granular
appearance – eosinophils and basophils are also granulocytes. The granules of
neutrophils release chemicals known as cytokines (chemotaxin) to attract
additional forces to the area under attack – these cytokines include pyrogens
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Bloodborne Pathogens
Module 2: The Immune System
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(fever producing cytokines) and other chemicals involved in the inflammatory
response.
Link to Chemotaxis movie: http://www.cellsalive.com/chemotx.htm
Neutrophils spend their lives in circulating blood, but are able to squeeze through
pores in the capillary endothelium to attack tissue invaders.
Agranulocytic leukocytes
Monocytes
Monocytes comprise 1-6% of the total population of leukocytes circulating in the
blood. Monocytes are precursor cells for tissue macrophages and are found in
circulating blood en route from the bone marrow to tissues where they enlarge
and mature to macrophages. Macrophages are the equivalent of garbage
disposal units or trash compacters, ingesting and destroying bacteria, and other
particles like old red blood cells and dead neutrophils.
Link
to
Macrophages
taking
http://www.bio.davidson.edu/courses/movies.html
a
walk:
Included in the group of leukocytes known as macrophages are monocytes found
in the blood and specialized cells found in the liver, skin, brain, bone and lining of
the abdomen.
Link
to
Monocyte
image:
medlib.med.utah.edu/WebPath/HEMEHTML/HEME003.html
http://www-
Successful hunters display their trophies on walls and mantles and, seeing these,
visiting friends seek to emulate them. Similarly, macrophages are also involved in
the stimulation of lymphocytes – as antigens are digested, antigen fragments are
displayed on the outer surface membranes. And, like the hunter’s visiting friends,
visiting lymphocytes are stimulated to produce antibodies against the antigen to
obtain kills of their own.
Lymphocytes
Lymphocytes comprise approximately 20-35% of the total leukocyte population in
circulating blood. However, only 5% of all lymphocytes are found in the
circulation normally, the remainder are found in the spleen, thymus, lymph nodes
and other lymphatic tissue.
Link
to
Lymphocyte
image:
medlib.med.utah.edu/WebPath/HEMEHTML/HEME002.html
http://www-
In addition to being grouped by morphological characteristics, leukocytes can
also be grouped according to their mode of function – neutrophils, eosinophils,
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Bloodborne Pathogens
Module 2: The Immune System
Page 16
basophils and monocytes are phagocytic cells, while lymphocytes, also referred
to as immunocytes, are responsible for specific immune response.
Lymphocytes secrete cytokines and are involved in antigen-specific responses.
Interleukin is the primary cytokine produced by lymphocytes.
There are three main types of lymphocytes:

B-lymphocytes – develop into memory cells or plasma cells that secrete
antibodies

T-lymphocytes – develop either into cells that attack and destroy virusinfected cells or cells that regulate other immune cells

Natural killer cells – attack and destroy virus-infected and tumor cells
In the course of development from precursor cells into functionally mature forms
in the thymus, lymphocytes display a complex pattern of surface antigens on
their cell surface – these antigens are known as cluster of differentiation (CD)
antigens. CD antigens are also expressed on the surface of macrophages.
CD antigens are uniquely expressed on the surface of all lymphocytes, and serve
as biochemical markers characteristic for a particular cell type indicating the
lineage or stage of maturity. CD antigens are designated CD1, CD2, CD3, CD4,
etc. In many instances CD antigens are expressed only at certain stages of
development, and the functions of many of the 247 currently recognized CD
proteins are still unknown.
Dendritic cells
Dendritic cells are antigen-presenting cells that patrol skin and other organs.
Dendritic cells recognize and capture antigens, then migrate to lymphoid tissues
where the antigens bound to the surface of dendritic cells are presented to
lymphocytes, thereby activating the lymphocytes.
Test your memory – Link to the blood smear and identify the WBCs – to find out
if you’re correct, place your mouse on the cell and check your identification
against the one that appears in the box at the top of the image
http://www-medlib.med.utah.edu/WebPath/HEMEHTML/HEME100.html