Immunology
AP Book – Chapter 43
IB Study Guide Book – Chapter 11
IB Standards – 6.3 & 11.1
Gail Kelly
Laura Kate Snyder
Sarah Weinsztok
Introduction to Immunity
Pathogen- any organism or virus responsible for disease…or a
disease producing agent
Antigen- anything that elicits an immune response
Lymph system functions (circulates white blood cells through the
body, like blood)
White Blood Cells = Lymphocytes
Major players of the immune system
Thymus
Bone marrow (where ALL red and white blood cells are
initially created)
Spleen
Introduction to Immunity
Non-Specific (Innate) Specific (Acquired)
1st – External defense 3rd – Specific defense
Skin B cells = Humoral response
Mucous membranes Antibodies
Secretions T cells = Cell-mediated
2nd – Internal defense response
Phagocytic cells Cytotoxic lymphocytes
Antimicrobial proteins
Inflammatory response
Natural Killer cells
Active and Passive Immunization
Immunity is any resistance to an infection
Active Immunity (IB 11.1.3)
Depends on a person’s own lymphocytes and memory
cells
Develops after production of antibodies (after the
defense mechanisms are stimulated by antigens) or
vaccination (immunization)
Ex. When a infection with rubella virus causes
immunity to rubella; re-infection is rare
Active and Passive Immunization
Vaccinations (IB 11.1.6)
Include bacterial toxins, killed microbes, weakened
microbes, and genes with microbial proteins; these
stimulate immunity to a disease without actually
developing the disease
The agents produce an immediate response and,
because of memory cells, long lasting immunological
memory
Someone who was vaccinated will have the same
response as someone who was previously infected
with the pathogen
Active and Passive Immunization
Benefits of Vaccinations (IB 11.1.7)
Epidemics can be prevented; some diseases can be
completely destroyed (ex. Smallpox and polio)
Deaths due to disease can be prevented (ex. Measles is
a major cause of death in some parts of the world)
Disability due to disease can be prevented (ex.
Deafness and blindness in babies whose mothers
contracted rubella during pregnancy)
Active and Passive Immunization
Dangers of Vaccinations (IB 11.1.7)
CAN cause fever, pain, swelling, and redness, and even
a rare but sever allergic reaction (anaphylaxis)
Since the vaccines make diseases rare, parents begin to
worry more about the vaccine than the actual
disease affecting their child
Active and Passive Immunization
Passive Immunity (IB 11.1.3)
Transferring antibodies from someone who is immune
to an infectious agent (because of active immunity)
to someone who is not
Does not result from your own B and T cells
Ex. First milk produced after birth, colostrum, has
antibodies that will line the gut of babies, helping
prevent infection
Ex. Antibodies can be injected to treat virulent diseases
like rabies
Antibody Production
Clonal Selection- B-cells produce antibodies; if
those contact an antigen, they multiply to
clone many cells
Polyclonal Selection- Several antibodies bind
to one antigen
Challenge and Response- Immunity to a disease
is only developed if it challenges the immune
system
Antibody Production
1. Antibodies are made by lymphocytes
2. Each of many lymphocytes put a part of the antibody
it can make into its plasma membrane
3. A pathogen enters the body and the antigens bind to
the antibodies in the plasma membrane
4. The lymphocyte becomes active and starts mitosis to
make many identical cells
5. The clones make the same antibody to defend the
body against the pathogen
*Good illustration in your IB books on page 50*
Allergies
Allergies- exaggerated responses to allergens (types of
antigens); most common include IgE antibodies
Ex. Hay Fever- cells discharge IgE antibodies specific for
antigens on pollen; some of the antibodies attach to
mast cells by their tails; when pollen grains enter the
body, they attach to those sites of mast cells; the
mast cell is then made to release histamine and
other inflammatory agents from vesicles (this
process is called degranulation)
This leads to sneezing, runny nose, teary eyes, etc.
Allergies
Anaphylactic shock- a whole-body, life-threatening
allergic response that can occur within seconds of
exposure
Develops when widespread degranulation starts an
abrupt dilation of peripheral blood vessels, causing a
drop in blood pressure
Can cause death within minutes if not treated; people
with these hypersensitivities carry syringes with the
hormone epinephrine (epi pen)
Autoimmune Diseases
The immune system has the chance of losing tolerance
for itself, causing an autoimmune disease
Ex. Systemic lupus erythematosus (lupus)- skin rash,
fever, arthritis, kidney dysfunction; the system makes
antibodies (autoantibodies) that harm self
molecules, like histones and DNA
Ex. Multiple sclerosis (MS)- several neurological
abnormalities like loss of balance, numbness or
tingling, dizziness, etc.; T-cells destroy the myelin
sheath surrounding some neurons in the CNS
Inborn Immunodeficiencies
Inborn (Primary) Immunodeficiency- a disease cause
by a defect in either genes or development in the
immune system
Innate and/or acquired defenses can be affected
Severe Combined Immunodeficiency (SCID)- humoral
and cell-mediated branches fail to function; survival
requires a bone marrow transplant to supply
functional lymphocytes
Acquired Immunodeficiencies
Acquired (Secondary) Immunodeficiency- a disease
that develops after exposure to chemical or
biological elements
Ex. Drugs supposed to fight autoimmune diseases or
prevent rejection of a transplant overpower the
immune system
These can be temporary (ex. stress) or devastating
(ex. AIDS)
Stress
Healthy immune function has been proven to depend
on the endocrine and nervous systems
Both physical and emotional stress can put a strain on
the immune system; the adrenal glands secret
hormones during stress that affect the numbers of
white blood cells
Neurotransmitters that are secreted when relaxed or
happy can boost immunity
Acquired Immunodeficiency Syndrome
AIDS is a syndrome (a group of symptoms found
together)
People with AIDS have low numbers of one kind of
lymphocyte, as well as weight loss and different
diseases due to viruses, bacteria, fungi, and protozoa
These weaken the body and will eventually lead to
death
Acquired Immunodeficiency Syndrome
Cause (IB 6.3.7 and 6.3.8)
Human Immunodeficiency Virus (HIV) infects certain
lymphocytes that have vital roles in antibody
production. Over several years, these are destroyed
and antibodies can’t be produced. Without a capable
immune system, the entire body becomes more
vulnerable to pathogens that should normally be
controlled easily.
Acquired Immunodeficiency Syndrome
Transmission (IB 6.3.8)
HIV can’t live long outside the body or pass easily
through skin, so transmission implicates a transfer of
body fluids from an infected person to an uninfected
person
Ex. Cuts or tears during vaginal, anal, or oral sex
Ex. Blood on a hypodermic needle shared by drug
abusers
Ex. Transfused blood or products like Factor VIII (a
blood clotting factor) in treatment of hemophiliacs
Acquired Immunodeficiency Syndrome
Social Implications (IB 6.3.8)
Grief by family and friends
The person with AIDS can be refused life insurance; if
they were the wager earner, the family may
experience financial problems
People with HIV are belittled and may not find
partners, work, or even housing
Fear of AIDS may reduce sexual activity in a population