Differential expression of PKCα and PKCβ isozymes in CD4+, CD8+ and CD4+/CD8+ double positive human T cells

Using specific monoclonal and polyclonal antibodies, we have analyzed protein kinase C α and β isozyme expression in human T cells from peripheral blood (PB) and from thymus. While the PKCβ isozyme was present in all T cell sub-types isolated from both PB and thymus, the α 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+ thymocytes. These results show that PKCα and -β are differentially regulated during intra-thymic development and suggest that PKCα plays a specific role in helper T cell function.