Phenotypic expression of B-lymphocytes. 1. Identification with monoclonal antibodies in normal lymphoid tissues.

Marker expression is highly variable among different stages of B-cell activation. In peripheral lymphoid tissues, architecturally and cytologically three or four types of B cells can be identified, thus allowing an investigation of cellular surface or cytoplasmic phenotypes. Mantle zone lymphocytes of follicles are phenotypically similar, if not identical, to peripheral blood B-lymphocytes and express the following markers: B1, B2, BA-1, HLA-DR, Leu 10, A1G3, Leu 8, and T200. The germinal center is composed of two main populations, centroblasts and centrocytes which express the following markers: B1, BA-2, J5, OKT9, HLA-DR, Leu 10, and T200. This phenotype is similar to that of activated B cells or pre-B cells. Although membranous OKT10 is present in cortical thymocytes, the presence of cytoplasmic OKT10 appears to be a useful marker for plasma cells, terminally differentiated B cells, which also express A1G3 and T200. This study also revealed that a subpopulation of T cells in the germinal center express different markers (A1G3-/Leu 8-) as compared with that of most T cells in the T-dependent zone (A1G3+/Leu 8+).