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Flashcards in Humoral Immunity Deck (63)
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1

Which immunoglobulin isotypes can cross the placenta?

IgG

2

What complement protein subunit initiates the formation of the membrane attack complex?

C5b

3

What are the polypeptide chains that make an antibody?

2 identical heavy chains
2 identical light chains

4

What chromosome are the heavy chain genes on?

14

5

What chromosome are the light chain genes on?

2 (kappa) and 22 (lambda)

6

In early B-cell differentiation what are the bone marrow genes rearranged to generate?

Immunologlobulins

7

Which comes first; the Ig heavy or light chain?

The heavy chain comes first

8

What are the protective mechanisms of binding antibodies to anitgens?

Agglutination
Opsonization
Neutralization
Activation of complement
Inflammation
Antibody-dependent cell-mediated cytotoxicity

9

What does agglutination do?

Enhances phagocytosis and reduces the number of infectious units to be dealt with

10

What does neutralization do?

Blocks adhesion of bacteria and viruses to mucosa and blocks active site of toxin

11

What are the characteristics of follicular B cells??

T-dependent isotype-switched high affinity; long lived plasma cells

12

What are the characteristics of marginal zone B cells?

T-independent (IgM); short lived plasma cells

13

What are the characteristics of B-1 B cells?

T-independent (IgM); short lived plasma cells
CD5 positive

14

What are T-independent antigens?

Polysaccharides, nucleic acids, lipids

15

What are T-dependent antigens?

Protein antigens

16

What are the secondary immune organs?

The lymph nodes and the spleen

17

What is somatic hypermutation (SHM)?

Introduction of a single nucleotide substitution (point mutation)
Follows B-cell activation by an antigen
More common in the V chain of heavy chain (results in higher affinity)

18

What is class switching?

Process by which an Ig changes class or isotype
The antigenecity is preserved

19

Where does class switches occur?

On the heavy chain

20

When does class switching occur and what happens during it?

It occurs during the immune response and invovles the deletion of the C segment

21

What are some of the factors in immunoglobulin diversity?

V(D)J recombination
Somatic hypermutation
Class switching
RAG1/RAG2
Base excision and repair

22

What is hyper IgM syndrome?

Results from mutations affecting class switching which is rare
Decreases the IgG, IgA, IgE

23

How do you treat hyper IgM syndrome?

IVIG, BMT

24

Describe to me IgM;

A pentamer which is the first Ig made by a fetus and B cells
Expressed as membrane bound Ig
Opsonization (Fc receptor - phagocytes)

25

Where is IgM present in the mother?

In colostrum (momma milk) to protect newly born

26

Is IgM produced in secondary immune response?

Sometimes

27

Tell me about IgG;

Major serum Ig and most abundant
Major immunoglobulin of secondary immune response and in the extravascular spaces
Involved in opsonization

28

Which Igs fix complements;

IgM, IgG

29

Explain the IgA;

Found in serum and body secretions, major secretory Ig on mucous surfaces

30

Where is IgA present in the mom?

Colostrum and momma milk