DIFFERENTIAL EXPRESSION OF PKC-ALPHA AND PKC-BETA ISOZYMES IN CD4(+),CD8(+) AND CD4(+) CD8(+) DOUBLE-POSITIVE HUMAN T-CELLS/

Using specific monoclonal and polyclonal antibodies, we have analyzed protein kinase C alpha and beta isozyme expression in human T cells fr om peripheral blood (PB) and from thymus. While the PKC beta isozyme w as present in all T cell sub-types isolated from both PB and thymus, t he a isozyme was found only in single positive CD4(+). thymocytes, in PB-CD4(+) lymphocytes and in PB-CD8(+) T cells from several donors. It was absent from both, CD8(+) and double positive CD4(+)/CD8(+) thymoc ytes. These results show that PKC alpha and -beta are differentially r egulated during intra-thymic development and suggest that PKC alpha pl ays a specific role in helper T cell function.