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Test 3 Material
Adaptive Immunity
47
Microbiology
Undergraduate 2
03/27/2010

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Term
Important aspects of adaptive immunity
Definition
1. antigen-specific

2. systemic

3. is learned

4. has memory
Term
2 types of adaptive immunity
Definition
1. cell-mediated immunity

2. antibody-mediated immunity
Term
cell mediated immunity steps
Definition
1. an antigen evades body’s innate defenses
2. antigen is taken up by an antigen-presenting cell (APC; dendritic cells) and broken down
3. antigen fragments merge with MHC proteins on the APC’s membrane
4. T-cell comes into contact with APC, recognizes the “new” MHC protein and becomes active
5. activated T-cells divide & differentiate
Term
MHC
Definition
special protein imbedded in a cell’s membrane; allows for the recognition of self

Stands for major histocompatability complex
Term
cytotoxic T-cells (CD8 cells)
Definition
1) primarily attack cells infected by viruses or other intracellular microbes, cancer cells, & transplanted cells
2) activation results in apoptosis of target cell
a) deprives antigen of host & exposes it to antibodies
3) mechanism isn’t completely understood but some possibilities include:
a) secretion of perforin & granzymes
i) perforins create pores in the target cell’s membrane allowing granzymes to
move in & degrade interior cellular components
b) secretion of a lymphotoxin into target cell fragmenting its DNA
Term
apoptosis
Definition
a specialized cell destruction that releases no toxins
Term
Helper T-cells (CD4 cells)
Definition
1) produce a # of interleukins (IL’s)
a) IL-2 – stimulates T-cell proliferation
b) IL-4 – promotes T-cell growth; stimulates production of IgE
c) IL-5 – promotes the secretion of IgA
2) stimulates the production of other T & B cells
Term
Cells in cell mediated immunity
Definition
Cytotoxic T cells

Helper T cells

Suppressor T cells

Memory T cells
Term
Antibody-mediated immunity
Definition
1. cell-mediated response has occurred
2. helper T cells activate the response
A) stimulate B cell division & differentiation
1) plasma cells & memory B cells
B) enhance antibody production
3. antibody merges w/ antigen = antigen-antibody complex
4. antibody cause destruction of antigen
Term
neutralization
Definition
bind to toxins or virus rendering them useless
Term
immobilization
Definition
bind to cilia or flagella slowing antigen movement
Term
destruction of the antigen
Definition
A) neutralization
B) immobilization
C) attraction of phagocytes
D) enhances phagocytosis
1) aids adherance
E) stimulate inflammation
F) inhibit antigen metabolism
Term
5 classes of antibodies (immunoglobulins)
Definition
IgA

IgE

IgD

IgM

IgG
Term
IgA
Definition
found in blood plasma

1) prevents pathogens from adhering to epithelia and penetrating tissues
Term
IgD
Definition
integral part of B cell membrane

1) acts as an antigen presenter
Term
IgE
Definition
found mainly in tonsils, skin, and mucus membranes

1) stimulates mast cells (basophils) to release contents and attracts eosinophils to
parasitic worm infections
Term
IgG
Definition
75-85% of circulating antibodies in plasma

1) crosses placenta to confer temporary immunity to the fetus
Term
IgM
Definition
found on the B cell membrane and circulating in plasma

1) presence indicates a recent infection
Term
Vaccination definition
Definition
the practice of deliberately stimulating the immune system in order to protect individuals against a disease
Term
Vaccination facts
Definition
1. Edward Jenner developed the first official smallpox variolation technique using cowpox virus
2. Pasteur used the word vaccination from the Latin word vacca meaning “cow”
3. It is possible for a portion of a population to become immune to a disease, either through natural immunity or vaccination
A) herd immunity – the inability of an infection to spread within a population due to
the lack of susceptible hosts
Term
Naturally acquired immunity
Definition
acquisition through normal events
Term
artificially acquired immunity
Definition
acquisition via non-natural means
Term
Active immunity
Definition
the immunized individual makes their own antibodies
Term
Passive immunity
Definition
the immunized individual did not make the antibodies
Term
Naturally acquired-active immunity
Definition
natural exposure to an antigen causes the person to produce their own antibodies

A) ex. getting over chickenpox
Term
Naturally acquired-passive immunity
Definition
natural activities provide the individual with antibodies that someone else made after natural exposure to the antigen

A) ex. antibodies transferred from mother to child via breast milk or across the placenta
Term
Artificially acquired-active immunity
Definition
deliberate exposure to the antigen via an injection causes the person to make their own antibodies to the antigen

A) ex. immunization of children for measles
Term
Artificially acquired-passive immunity
Definition
deliberate introduction of antibodies made by some other individual into the body of the patient

A) ex. RhoGAM & antivenom
Term
Vaccine
Definition
a preparation of living or inactivated (dead) microorganisms, viruses, or their components used to induce active immunity
Term
Requirements of an effective vaccine
Definition
A) Safe
B) Few side effects
C) Provide lasting immunity against a specific illness by inducing antibodies, immune cells, or both
D) Low cost
E) Stable with a long shelf life
F) Easy to administer
Term
Attenuated vaccine (alive)
Definition
weakened form of disease-causing agent
1) generally unable to cause disease but can still induce immune response
2) attenuated strains typically produce infection w/ undetectable/mild symptoms
3) often only single dose is needed to induce long-lasting immunity
4) can be spread from immunized individual to non-immunized people, inadvertently immunizing the contacts
a) attenuated strains can cross the placenta and can be passed in breast milk
5) BC they can spread, they have potential of causing disease in immunosuppressed people
6) some can revert or mutate back into the disease-causing form
7) examples include tuberculosis, MMR, oral polio, and chickenpox
Term
Inactivated vaccines (dead)
Definition
forms unable to replicate but still cause an immune response
1) Can't cause infection, revert to dangerous forms, or be passed on to others
2) the magnitude of the immune response by inactivated vaccines is very limited
a) most require multiple exposures
3) many inactivated vaccines contain an adjuvant
a) ex: include aluminum phosphate & aluminum hydroxide
4) There are 2 general categories of inactivated vaccines: Whole agents, & fractions of the agent
Term
Adjuvant
Definition
a substance that enhances the immune response to antigen
Term
Whole agents
Definition
dead microorganisms or inactivated viruses; ex. influenza, rabies, and the injectable polio
Term
Fractions of the agent
Definition
only pieces of the microorganism that can induce an immune response
Term
Toxoids
Definition
inactivated toxins; ex. diphtheria and tetanus vaccines

(fractions of the agent)
Term
Protein subunit vaccines
Definition
composed of key protein antigens of the
infectious agent; ex. Hepatitis B and anthrax vaccines

(fractions of the agent)
Term
Polysaccharide vaccines
Definition
composed of the polysaccharides that make up the capsule of certain microorganisms; ex. Streptococcus
pneumoniae vaccine

(fractions of the agent)
Term
Serology
Definition
use of serum antibodies to detect and identify antigens, or conversely, use of known antigens to detect antibodies
Term
Titer
Definition
is a measure of the amount of specific antibody in serum
A) can determine a person’s level of immunity to a specific antigen
B) individuals exposed to an antigen for the first time usually do not have detectable
antibodies in the blood serum until about 7-10 days after infection
Term
Monoclonal antibodies
Definition
contain only one antibody with one specificity

A) commonly used in immunoassays
Term
Mechanism of Enzyme-Linked Immunosorbent Assay
Definition
a) Known antigen is attached to plastic wells.
b) The serum to be tested is added & incubated. If antibodies are present, they will bind to the antigen.
c) To detect if antigen-antibody reactions have occurred, anti-HGG is added.
d) The anti-HGG reacts with any bound antibodies & the excess is washed away.
e) A chromogen is added & colored end product is produced if antibodies were present.
Term
Examples of immunoassays
Definition
Enzyme-Linked Immunosorbent Assay (Elisa)

Western Blot

Fluorescent Antibody Technique
Term
What is ELISA used for?
Definition
detect HIV

Home pregnancy tests
Term
Western Blot
Definition
combination of electrophoresis with ELISA to separate and identify protein antigens in a mixture
Term
Fluorescent Antibody Technique
Definition
involves mixture of antigens, antibodies, and a fluorescent dye
Term
Indirect method of Fluorescent Antibody Technique
Definition
detects the presence of antibodies produced in response to an antigen; used to detect syphilis
i) a known antigen (ex. syphilis) is added to a sample of the patient’s serum along with a fluorescence-labeled antiglobulin antibody
(a) the antiglobulin antibody will only bind to an antibody bound to an antigen (i.e. it only binds if syphilis antibodies are present and bind to the added syphilis antigen)
ii) binding of the antiglobulin antibody causes illumination of the fluorescent dye
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