Where are the germinal centers located in the body?

Germinal centers: Primary lymph cell producing sites are the bone marrow and the thymus. Secondary sites are lymph nodes and the spleen.Germinal centers are sites within lymph nodes where mature B lymphocytes proliferate, differentiate, and mutate their antibody genes (through somatic hypermutation), and switch the class of their antibodies (for example from IgM to IgG) during a normal immune response to an infection