6) B cells and Humoral Immunity

Question 1

What Ab is produced by thymus-independent (TI) antigens?

Answer 1

IgM only

Question 2

VDJ genes coincides with which chain?

Answer 2

heavy

Question 3

VJ genes coincides with which chain?

Answer 3

light chains (keppa and lamda)

Question 4

What four things contribute to Ig diversity?

Answer 4

1) pairing of heavy and light chains
2) combinatorial diversity (gene rearrangement)
3) junction diversity (Tdt action)
4) somatic mutation (point mutations)

Question 5

True or False. Random gene rearrangement can result in DNA loss

Answer 5

TRUE.

Question 6

What term is used to describe single antigen-specificity ensured by only expressing one parental chromosome?

Answer 6

allelic exclusion

Question 7

Co-expression of IgM and IgD are due to…

Answer 7

alternative splicing

Question 8

Membrane versus secreted B cells are due to…

Answer 8

alternative splicing (secreted form do no have membrane-anchoring gene because it got spliced out)

Question 9

Isotype switching can be done in which level, DNA or RNA?

Answer 9

BOTH

Question 10

True or False. Isotype switching is a random process

Answer 10

FALSE. It is NOT random.

Question 11

Isotype switching is driven by…

Answer 11

cytokines

Question 12

True or False. B and T cells do no need to see the same epitope on an antigen.

Answer 12

TRUE. as long as they can recognize the antigen, it is okay

Question 13

What is analogous to TCR’s CD3?

Answer 13

Ig-alpha and Ig-beta

Question 14

these non-peptide antigens do not bind to Ig receptors on surface, but something else

Answer 14

TI-1 antigens

Ex. LPS

Question 15

these non-peptide antigens bind to Ig receptors and activate antigen-specific B cells

Answer 15

TI-2 antigens

Ex. polysaccharide with repeated epitopes