Question

Which factors on the surfaces of B cells and T cells, through their interaction, are required to allow germinal center formation to occur?

A. CD40 and CD40L
B. Fas and FasL
C. CD28 and CD80/86
D. TCR and MHC class II
E. None of the above

Answer 1

The factors required for germinal center formation through the interaction of surfaces on B cells and T cells are CD40 on B cells and CD40L on T cells.

Step-by-step explanation:

The interaction required for the formation of germinal centers, vital structures in the spleen and lymph nodes where B cells proliferate and differentiate, involves the binding of CD40 on B cells and CD40L (also known as CD154) on T cells. This interaction is crucial for B cell activation and the subsequent immune response, as it leads to the proliferation of B cells and their differentiation into plasma cells and memory B cells in the germinal centers.

The correct answer to the question, therefore, is A. CD40 and CD40L. These molecules play an essential role in the T cell-dependent activation of B cells, which is a more complex process compared to T cell-independent activation. The process involves B cell receptors (BCRs) binding to the antigen, internalizing it, and then presenting it on MHC II for recognition by helper T cells. The CD40-CD40L interaction, alongside the recognition of the antigen-MHC II complex by the TCR (T cell receptor) on helper T cells, signals the B cell to proliferate and form a germinal center.