Question

You've generated a mouse that doesn't form germinal centers. On stimulation of B cells with a T-dependent antigen, do you expect the mouse to be able to... Yes or No.

1. secret IgG antjbkdies specific for the antigen?

2. Secrete anitgen specific antibodies that'll undergo somatic hypermutation?

3. Secrete IgM antibodies specific for the antigen?

Answer 1

1. yes, on stimulation of B cells with a T-dependent antigen, the mouse will still be able to secrete IgG antibodies for the antigen, but it would not be highly effective due to its short life span and less affinity. This is because that B cells can undergo class switching and can produce different types of Abs once it is stimulated by the T cells, even in absence of germinal centres.

2. No in the absence of germinal centres, the mouse will not be able to produce the antigen specific antibodies beacuse it can't undergo the somatic hyermutation because it is the region where mutation occurs in the variable domain of the BCR receptors bye the enzyme AID ( activation induced cytidine deaminase)

3. yes, the cell will secrete IgM antibodies specific for the antigen because IgM is one of the first expressed isotype of the immunoglobulin on the B- cells with the initial exposure of the antigen.