Germinal center response is the highly organized immunological process occurring within specialized microenvironments of secondary lymphoid organs, primarily lymph nodes and spleen, following T cell-dependent antigen exposure. It is the critical site for B cell activation, rapid proliferation, somatic hypermutation of immunoglobulin genes, affinity maturation through selection, and differentiation into high-affinity antibody-secreting plasma cells and long-lived memory B cells, fundamentally underpinning the generation of robust and durable humoral immunity essential for protection against pathogens and effective vaccination.