Quick Facts
The germinal center is the spherical area in the center of a secondary lymphoid nodule containing mainly aggregations of actively proliferating B lymphocytes, developing in a primary lymphoid nodule in response to antigenic stimulation (Dorland, 2011).
Related parts of the anatomy
Structure/Morphology
The germinal center is found at the core of the secondary lymphoid nodule and is the site of activation, proliferation, differentiation, and death of B lymphocytes, or B-cells.
Germinal centers may by present for 2–3 weeks after antigenic stimulation. A mature germinal center has two populations of B-cells. Firstly, the large, densely packed centroblasts are found in the basal (dark) part of the germinal center. These cells undergo rapid proliferation and supply a second population of cells, centrocytes, to apical (light) zone of the germinal center. The centrocytes are smaller cells that are intermingled with a network of follicular dendritic cells. The dendritic cells display antigens on their cell surfaces to the centrocytes in turn, the centrocytes produce surface antibodies. Macrophages are also present and are responsible for removing B-cells that die during the maturation phase in the germinal center (Willard-Mack, 2006).
As mitotic activity begins to subside, the centrocytes differentiate into memory B-cells and plasma cell precursors. The plasma cell precursors migrate to the medullary cords to mature. The germinal cell then disappears if there is no further antigenic stimulation.
References
Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.
Willard-Mack, C. L. (2006) 'Normal structure, function, and histology of lymph nodes', Toxicologic Pathology, 5(34), pp. 409-424.
