The purpose of the present study was to examine protein kinase C (PKC) isotype expression in T lymphoblasts derived from peripheral blood and the T leukaemic cell Jurkat. Using antisera reactive with PKC α,β1, and β2 and γ, it was observed that T cells expressed two PKC isotypes, PKC α and β. No PKC γ was detected in T lymphocytes. In lymphoblasts, high levels of PKC β compared to PKC α were found whereas Jurkat cells expressed high levels of α compared to PKC β. Differences in the calcium sensitivity of phorbol ester-induced phosphorylation were observed in Jurkat and T lymphoblasts which correlated with the relative levels of PKC α and β isotypes expressed by the cells.
