Contrasting patterns of protein kinase activities among normal peripheral blood lymphocyte subpopulations and...

Human peripheral mononuclear cell suspensions were separated into E-rosette-positive (T cell) and E-rosette-negative (non-T cell) fractions and assayed for cAMP binding activity and histone and casein kinase activity, in the presence and absence of cAMP. Each of these activities was higher in E-rosette-positive than E-rosette-negative fractions. Cyclic AMP binding and histone kinase activities were further noted to be higher in T lymphoblastoid cell lines when compared to lines of non-T lymphoid cell origin. In addition. DEAE-cellulose chromatography revealed a qualitative contrast of isoenzymic composition of protein kinase from these cell lines. Cyclic AMP-independent casein kinase activity was high in both types of cell lines. These results suggest that high protein kinase activity is characteristic of T cells and may be related to their higher sensitivity to cAMP agonists in comparison to non-T cells. This study also provides further evidence for an association between increased cAMP-independent protein kinase activity and the transformed state, which has been noted for a variety of other cell types.