Question

which are true for the clonal selection of naive B lymphocytes

a. the CD4 protein must bind to the antigen fragment on MHC 2 of the target cell

b. the CD8 protein must bind to the antigen fragment on MHC 1 of the target cell

c. the alpha & beta subunits of the T cell receptor must bind to the antigen fragment displayed on the MCH 2 protein of the target cell

d. the CD4 proteins bind to the MCH 2 protein on the naive B lymphocyte cell

e. c & d are correct

Answer 1

Answer. d. the CD4 proteins bind to the MCH 2 protein on the naive B lymphocyte cell

B-cell antigen receptor delivers the antigen to intracellular sites where it is degraded and returned to the B-cell surface as peptides bound to MHC class II molecule. The peptide:MHC class II complex can be recognized by antigen-specific armed helper T cells, stimulating them to make proteins that, in turn, cause the B cell to proliferate and its progeny to differentiate into antibody-secreting cells. Some microbial antigens can activate B cells directly in the absence of T-cell help. The ability of B cells to respond directly to these antigens provides a rapid response to many important bacterial pathogens.