Immunological properties of Fc receptor on lymphocytes: 1. Functional differences between Fc receptor-positive and negative lymphocytes in humoral immune responses

Abstract

Using an EA rosetting system, it was observed that Fc receptors (FcR) were present on the surface of T cells as well as B cells, and that functional differences existed between FcR-positive (FcR +) and FcR-negative (FcR −) cells in both T and B cells in in vivo humoral immune responses. Approximately 15% of splenic T cells obtained by nylon wool passage are FcR +. The number of surface immunoglobulinbearing cells as detected by immunofluorescent staining accounted for less than 10% of these FcR + cells. FcR + and FcR − T+B-cell populations obtained from spleens contain 60 and 20% of surface immunoglobulin-positive cells, respectively. In the adoptive primary response in which horse RBC and dinitrophenyl-conjugated dextran (DNP-DE) were used as T-dependent and T-independent antigens, respectively, the majority of precursor B cells were FcR −. In the secondary response using hapten-primed B cells and carrier-primed T cells, the majority of memory B cells for a haptenic determinant were also FcR −. Furthermore, the majority of functional cells exerting helper activity in the same hapten-carrier system are FcR − cells, and FcR + T cells collaborate much less effectively with either memory B cells or helper FcR − T cells.