Figure 4.

Expression of protein kinase C (PKC) isoforms and PKCδ activity in different monocyte subsets. (a) Immunoblot analyses using isoform specific anti-PKC antibodies in non-apoptotic CD16⁻ and CD16⁺ monocytes from two independent donors (D1 and D2). Recombinant human PKC (rPKC) proteins were used as controls. The same membranes were re-probed with an anti-β-tubulin antibody. (b) Relative expression of PKC isoforms (Intensity/mm²) after normalization by the corresponding β-tubulin expression. Data represent mean ± SEM (n = 7, **P < 0·01). (c) CD16⁻ and CD16⁺ monocytes were cultured in serum-free media for 0·5, 1 and 2 hr and lysates were immunoprecipitated (IP) with anti-PKCδ or isotype control (IgG) antibodies, followed by in vitro kinase assays in the presence of [γ³²-P]-ATP and H2B as exogenous substrate. Phosphorylated H2B was visualized by autoradiography (pH2B) and the same membranes were re-probed with anti-PKCδ and anti-H2B antibodies. Data are representative of three experiments.