Germinal center reaction (GC reaction)

The germinal center (GC) reaction is a sophisticated biological process occurring within the follicles of secondary lymphoid organs, such as lymph nodes and the spleen, that is fundamental to the adaptive immune system's ability to produce high-affinity antibodies. During this reaction, antigen-activated B cells undergo rapid clonal expansion and genetic modification through somatic hypermutation and class-switch recombination, a process coordinated by interactions with T follicular helper (Tfh) cells and follicular dendritic cells (FDCs). The ultimate goal is the selection of B cell clones with superior antigen affinity, which سپس differentiate into long-lived memory B cells or antibody-secreting plasma cells. Dysregulation of the germinal center reaction is centrally implicated in the pathogenesis of B-cell malignancies, such as follicular lymphoma and diffuse large B-cell lymphoma, as well as in the production of pathogenic autoantibodies in diseases like systemic lupus erythematosus. Consequently, therapeutic strategies often focus on inhibiting specific molecular components of this reaction, such as CD40L or BCL6, to treat autoimmunity and lymphoma.

Other names

Germinal centre reactionGC responseGerminal center responseB-cell germinal center reactionAffinity maturation process

Inhibition of the germinal center reaction is achieved through several mechanisms: depletion of B lymphocytes, blockade of costimulatory signaling between B and T cells (e.g., CD40-CD40L or ICOS-ICOSL), inhibition of B-cell receptor signaling (via BTK), and direct suppression of key transcriptional regulators like BCL6.