Immune Response

Question 1

T/F: a microbe must be whole to be detected by immune cells and considered an antigen

Answer 1

FALSE

Antigens can be entire microbes, parts of microbes, bacterial toxins, pollen, transplanted organs, or incompatible blood cells

Question 2

5 Characteristics of Antigens

Answer 2

1. Immunogenicity
2. Specific Reactivity
3. Foreignness
4. Size
5. Shape

Question 3

Immunogenicity

Answer 3

Antigen’s ability to stimulate specific (humoral or cellular) immune response

E.g. the ability to cause the formation of Ab and T-cells

Question 4

Specific Reactivity

Answer 4

Capacity to be recognized by the Ab and T-cells
(E.g. ability to bind to the immune cells already produced)

Question 5

Foreignness

Answer 5

Ability to be recognized as non-self

Question 6

What size must an antigen be to be recognized?

Answer 6

At least 10 kd

Question 7

The extent of antigenicity is determined by…

Answer 7

The antigen’s tertiary and quaternary structures

Question 8

Antigens that are more _____ (simple/complex) are more likely to be detected

Answer 8

Complex

This is why plastics used in joint replacements are simple repeating subunits, to not elicit an immune response

Question 9

Eptitope

Answer 9

Antibody-binding site on the antigen
The binding triggers the immune response

Question 10

Hapten

Answer 10

Smaller substance that cannot trigger an immune response unless attached to body protein of Ab already formed

Question 11

What determines the great diversity of antigen receptors on immune cells?

Answer 11

Genetic Recombination of small gene segments

Question 12

Explain the process of antibody-mediated immunity binding

Answer 12

Antigen presented to B-cell in lymphatic tissue/organs and then B-cell differentiates into plasma cells to secrete Ab —> Ab circulates and attach to epitope of antigen

Question 13

Functions of an antibody (5)

Answer 13

1. Agglutination and precipitation
2. Neutralization
3. Immobilize
4. Complement Activation
5. Enhance Phagocytosis (via precipitation, complement, or opsonization)

Question 14

Antibodies consist of _____ chains, linked by ____ bonds

Answer 14

Polypeptide chains linked by disulfide bonds

Question 15

The c in Fc portion of an antibody stands for

Answer 15

Crystallizable

Question 16

Describe the structure of an antibody

Answer 16

T or Y shaped monomer of 4 polypeptide chains (2 heavy and 2 light)

Question 17

How does IgM bind to surfaces of B-cells?

Answer 17

Through the membrane, as an integral membrane protein

Question 18

T/F: Surface IgM are structurally different than circulating IgM

Answer 18

TRUE
In the Fc region

Question 19

What form of IgM is typically found in blood?

Answer 19

5-unit macromolecules (pentamers)

Question 20

Which antibody is the first to be produced in response to an infection?

Answer 20

IgM

Question 21

Which antibody can exist as a monomer or a dimer?

Answer 21

IgA

Question 22

Most abundant Ab in blood?

Answer 22

IgG

Question 23

Ab found most in response to parasitic infections

Answer 23

IgE

Question 24

Which Ab is secreted the least?

Answer 24

IgD

Question 25

IgA is most common and most active where?

Answer 25

Mucosal surfaces

Question 26

The dimeric Ab is bound together via

Answer 26

J chain

Question 27

How does IgA transport through cells?

Answer 27

It receives a secretory (“pass”) from epithelial cells that binds to its surface and allows it through

Question 28

What is colostrum? What Ab is associated with it?

Answer 28

First secretion of breast milk, after birth Associated w/ IgA

Question 29

What Ab is the only class able to pass placental barrier

Answer 29

IgG

Question 30

Which Ab is the best for opsonization?

Answer 30

IgG

Question 31

Which Ab is associated with Type 1 Hypersensitivity reactions?

Answer 31

IgE

Question 32

What are the differences between primary and secondary response?

Answer 32

Primary: slow onset, low in magnitude, short lived, IgM Secondary: rapid, high in magnitude, long-loved, IgG (or IgA, IgE)

Question 33

HLA

Answer 33

Human Leukocyte-Antigen System — group of proteins called Major Histocompatibility Complex (MHC) presented on cell surfaces and help distinguish between self-cells and foreign cells.

Question 34

Which class of MHC (I/II) is found on almost *all* cells? What are the types?

Answer 34

MHC 1: A, B, and C

Question 35

Which class of MHC (I/II) is found on *immune* cells? What are the types?

Answer 35

MHC II: D (DP, DQ, DR)