[Changes in distribution and isoenzymatic expression of protein kinase C in B lymphocytes induced by alloantigenic...

Protein kinase C comprises a family of distinct isoenzymes that are involved in signal transduction pathway triggered by activation of membrane receptor. These isoenzymes differ in their tissue distribution, activation requirements and substrate specificity. Recent reports have shown the regulation of PKC-isoenzymes expression in physiological and pathological models. Recently, we shown PKC participation in B cells allogeneic response to intact cells and solubilized alloantigen. Here, alloimmunization influence upon PKC isoforms expression on murine B cells was analyzed. Our data indicates that PKC beta is the main isoform expressed on B cells with a lesser amount of alpha, epsilon and zeta and a very small amount of delta isoform. When analyzing B cells from alloimmunized mice we observed an increment of isoforms a and e and a decrease of the beta isoforms while increasing the number of immunizations. An increase of membrane bound PKC enzyme was also observed. Furthermore with increasing number of immunizations a decrease in LPS induce proliferation was found. In contrary, while normal B cells showed non proliferation when stimulated with solubilized alloantigen, they displayed a strong proliferation when they were obtained from animals with 5-6 alloimmunizations. This results shown that alloimmunization induces changes in the distribution and expression of PKC isoenzymes that are correlated to changes in the biological response triggered by B cell stimulation.