[Demonstration of transcriptional regulation of protein kinase C by class II anti-HLA antibodies in human CA cells of the lymphoblastoid line].

HLA class II antigens are involved in signal transduction in B lymphocytes. We have previously reported that the ligation of HLA class II antigens in B cells results in an increase of cytosolic and membrane PKC activity [3]. Unlike TPA, no translocation of the cytosolic PKC was observed following anti HLA class II antibody treatment. However, an increase of both PKC activity (cytosolic and membrane) and quantity was observed. These effects are completely abolished by actinomycin D treatment. Northern blot analysis and PCR reaction revealed that anti HLA class II antibodies induce an increase of the PKC beta level which is significant after 20 minutes of stimulation and rose to a maximum after 60 minutes. Taken together, our results show that anti HLA class II antibodies exert a transcriptional regulation of PKC in human B lymphocytes.