Antibodies, Antibody Diversity, and T Cell Development

Question 1

What is an antigen?

Answer 1

Anything that can be SPECIFICALLY bound by cells of the adaptive immune system (B Cell receptor, T Cell receptor)

Question 2

Which cells bind in a specific manner to antigen?

Answer 2

Lymphocytes

• B Cells
• T Cells

Question 3

Recognition of antigen by B cell receptors will result in ______ secretion by ______ and development of immunological _______.

Answer 3

Antibody
Plasma Cells
memory

Question 4

Recognition of antigen by T cell receptors will result in T cell activation which will secrete _____ or become ____ cells.

Answer 4

cytokines

Natural Killer

Question 5

What are the two forms of antibody?

Answer 5

1. Membrane bound (b cell receptor)

2. Secreted

Question 6

What are four functions of antibodies?

Answer 6

1. Antigen Recognition
2. Direct antigen neutralization
3. Opsonization
4. Activation of the complement cascade (results in lysis)

Question 7

____cells do NOT require antigen presentation, ___ cells do (MHC).

Answer 7

B

T (MHC)

Question 8

Where do B cells complete their maturation?

Answer 8

Bone marrow

Question 9

Where do T cells complete their maturation?

Answer 9

Thymus

Question 10

What is hematopoiesis?

Answer 10

Production of RBCs, Platelets, and WBCs from bone marrow:
Stem Cell –> common myeloid progenitor, common lymphoid progenitor
CMP–>basophil, neutrophil, eosinophil, monocyte
CLP–> B lymphocytes, T Lymphocytes

Question 11

True or False: These stages of maturation [Stem Cell->ProLymphocyte-> PreLymphocyte-> Immature Lymphocyte] will occur without antigen presence.

Answer 11

True

Question 12

The lymphocyte will go from immature to mature when ______ is present in the bone marrow.

Answer 12

Self-antigen

Question 13

The lymphocyte will change from “mature” into a “differentiated effector” when _____ is present. This occurs in _____ _______ organs or tissue.

Answer 13

Foreign Antigen

peripheral lymphoid

Question 14

Lymphocytes with high avidity for self-antigen will result in ______ selection.

Answer 14

Negative (removal)

Question 15

Low avidity interactions with self-antigen will result in _____ selection of lymphocytes.

Answer 15

Positive (clonal expansion/differentiation)

Question 16

What are the primary functions of Antibodies?

Answer 16

1. Ag binding and recognition

2. Trigger the elimination of foreign Ag

Question 17

True or False: Binding alone may be sufficient for Ab to neutralize Ag.

Answer 17

True

Question 18

If antibody triggers the elimination of Ag, what are the three possible mechanisms?

Answer 18

1. Cell Lysis (through activation of complement)
2. Phagocytosis (after opsonization)
3. NK mediated cytotoxicity

Question 19

What are the two fragments of an antibody?

Answer 19

Fab (highly variable, antigen-binding fragment)

Fc (crystallized fragment)

Question 20

Describe the four chain structure of an antibody.

Answer 20

2 identical heavy chains (spanning Fab and Fc)

2 Identical light chains (spanning Fab only)

Question 21

Differences in antibodies exist within the _____ chains.

Answer 21

Heavy

Question 22

How are heavy chains indicated when listing different immunoglobulins?

Answer 22

The letter following “Ig”

IgM, IgA, IgD, IgE, IgG

Question 23

Which immunoglobulin is found in mucosal areas? How many types are there?

Answer 23

IgA

Two types: bound and secreted

Question 24

Which immunoglobulin has four types?

Answer 24

IgG

Question 25

Which immunoglobulin is involved in allergic responses (histamine release) and parasitic infections?

Answer 25

IgE

Question 26

Which immunoglobulin is found circulating in the highest levels and is capable of crossing the placenta?

Answer 26

IgG

Question 27

Which immunoglobulin indicates an early stage of infection?

Answer 27

IgM

Question 28

Which immunoglobulin activates basophils and mast cells?

Answer 28

IgD

Question 29

Early stages of infection will involve the presence of ____ and ____.

Answer 29

IgD | IgM****first

Question 30

Presence of ____ indicates late stages of infection.

Answer 30

IgG

Question 31

Fab arms are linked to Fc by an extended region of polypeptide chain known as the _____.

Answer 31

Hinge

Question 32

What are the two forms of light chains?

Answer 32

Kappa | Lambda

Question 33

How many subclasses of heavy chains are there?

Answer 33

four | y1, y2, y3, y4

Question 34

Antigens bind to the _______ regions of an antibody.

Answer 34

Hypervariable (CDR) | [complementary determing region]

Question 35

By what mechanism does the body make so many different antibodies?

Answer 35

VDJ Rearrangement

Question 36

The human heavy chain variable region is constructed of ____ gene segments; the light chain variable region is constructed by the joining of ____ gene segments.

Answer 36

Three (VDJ) | Two (VJ)

Question 37

What are the three gene segments associated with heavy chain variability?

Answer 37

V (variable) D (diversity) <--not present in light chain J (joining)

Question 38

What is "the creation of antibody diversity through the joining of various gene segments"?

Answer 38

V(D)J Recombination

Question 39

What is somatic mutation?

Answer 39

After antigen stimulation, the VDJ genes in B cells can make single base changes that increase the affinity of antibody (affinity maturation)

Question 40

Where does somatic hypermutation usually occur?

Answer 40

the hypervariable region (CDR)

Question 41

BCR on a naive B cell can only be ____ or ____.

Answer 41

IgM | IgD

Question 42

A plasma cell CAN secrete all of the antibody isotypes but a PARTICULAR plasma cell will secrete ______.

Answer 42

ONE form of antibody

Question 43

_____ ______ allows for the generation of multiple antibody isotypes with the same Ag specificity.

Answer 43

Class Switching

Question 44

Once a plasma cell is determined to be a particular antibody type, the other genes are removed via a ________ process.

Answer 44

Loop and Cut

Question 45

T cells mound an immune response against ______ antigens.

Answer 45

Non-self

Question 46

When T cells leave the bone marrow, the do not have a ____ and will acquire one in the thymus.

Answer 46

TCR

Question 47

Those T lymphocytes that do not bind MHC through their TCR are destined for _______ .

Answer 47

Apoptosis

Question 48

Low avidity interaction with self-antigen results in positive selection within the ______ region of the thymus.

Answer 48

Cortical

Question 49

High avidity interaction with self-antigen results in negative selection within the _____ region of the thymus.

Answer 49

Medullary

Question 50

In order for T cells to expand and differentiate, what are the two requirements?

Answer 50

1. Bind self-antigen at LOW-avidity | 2. Bind MHC

Question 51

A T cell is destined for apoptotic cell death if it has a "lack of positive selection" because _______ or if it has "negative selection" because ________.

Answer 51

lack +selection = cannot recognize MHC | - selection = binds self at high avidity

Question 52

A T cell is rescued from apoptotic cell death if _______.

Answer 52

The thymocyte recognizes MHC and engages in a low avidity interaction (positive selection)