The Germinal Center Is a Region Within the Secondary B

The germinal center is a region within the secondary B cell follicle where sustained B cell proliferation and differentiation take place. The processes of B cell proliferation and differentiation, including affinity maturation and class switching, require periodic interactions of the germinal center B cells with CD4 T_FH cells. These periodic interactions between the B cells and T_FH cells can occur:

A) When B cells cycle between the dark zone and the light zone of the germinal center
B) When B cells leave the germinal center and migrate through the T-cell zone on their way to the blood
C) When B cells migrate and form a primary focus of antibody-secreting plasmablasts in the medullary cords of the lymph node
D) When B cells migrate to the border between the T-cell zone and the B-cell zone of the lymph node
E) When B cells up-regulate CXCR4 and migrate into the dark zone of the germinal center