B cell immunity

Question 0

Why doesn’t T-independent B cell activation produce memory?

Answer 0

CD40L produced by Th cells in T-dependent B cell activation is required for differentiation of activated B cells into memory cells

(T-dependent B cells activation is also more robust than T-independent because CD40L promotes class switching and somatic hypermutation.

Question 1

what process is AID (activation induced cytidine deaminase) crucial for?

Answer 1

isotype switching

Question 2

List in order the antibody isotype genes from upstream to downstream

Answer 2

IgM, IgD, IgG, IgA, IgE

Question 3

Which antibody is the culprit behind allergies and anaphylactic shock?

Answer 3

IgE (IgE also defends against parasites)

Question 4

Which antibody can cross the placenta?

Answer 4

IgG

Question 5

Which antibody is resistant to stomach acid?

Answer 5

IgA

Question 6

When IFN-gamma is produced it triggers a switch to which antibody isotype?

Answer 6

IgG

Question 7

When TGF-beta is released it triggers a switch to which isotype?

Answer 7

IgA

Question 8

How long do plasma cells typically live and why?

Answer 8

Plasma cells typically live for just a few days. Their relatively short life span is a result of a trade-off between survival and function. Plasma cells work furiously during their short lifespans producing antibodies at a very high rate. The cellular machinery is devoted to this short burst of productivity.

Question 9

what is cross-linking?

Answer 9

clustering of receptors on the cell membrane; cross-linking usually leads to activation of a particular receptor-mediated pathway

Question 10

extra credit: In addition to cross-linking of antigen bound receptors and binding of costimulatory molecules, what additional process aids in activation of a B cell

Answer 10

binding of complement fragments on opsonized antigen (basically lowers the activation energy or number of clustered BCR’s required to precipitate a response)