CD27 expression by a distinct subpopulation of human B lymphocytes

Abstract

CD27 is present on the surface of a major subset of peripheral blood T lymphocytes. In this report we show that CD27 is also expressed on a subpopulation of the normal human B cell lineage which is absent from cord blood but present in tonsils and in the peripheral blood of adult individuals. CD27⁺ B lymphocytes are characterized by the following criteria: (a) in terms of physical properties, the CD27⁺ B cells form a population with an increased cell size combined with a decreased cell density; (b) the CD27 expression of tonsillar B lymphocytes is positively correlated with mIgA but negatively correlated with membrane IgM/membrane IgD positivity; (c) CD27 on B cells can be induced selectively by the combination of Staphylococcus aureus plus interleukin 2, but not by either treatment alone, and (d) CD27⁺ B lymphocytes express high levels of the adhesion structures LFA‐1 (CD11a), ICAM‐1 (CD54), LFA‐3 (CD58) and of the lymphocyte homing receptor CD44. These latter findings suggest that CD27⁺ B cells are predisposed to form cell‐cell interactions. Accordingly, within 3 h of cell culture CD27⁺, but not CD27⁻, B lymphocytes were found to form LFA‐1‐mediated homotypic B cell clusters.