TNF-alpha is a pleiotropic cytokine produced by activated T-cytotoxic lymphocytes and NK cells that is involved in signal transduction after interacting with the appropriate cell surface receptors. The modulation of signals by TNF-alpha receptor super-family is involved in the regulation of cell activation, proliferation, differentiation and control of the cell survival including cell death by apoptosis and necrosis. We have monitored the kinetics of apoptosis/necrosis on PC cells, after TNF-alpha exposure of pre-treated cells to anti-CD95 and anti-CD45 monoclonal antibodies. The results showed that in comparison with untreated cells, TNF-alpha, after 6-24 h of incubation significantly increased apoptosis and necrosis in PC cells. These effects were significantly different in comparison to both untreated cells and cells pre-treated with anti-CD45 monoclonal antibodies. However, TNF-alpha on PC cells pre-treated with anti-CD95 monoclonal antibody significantly decreased apoptotic and necrotic form of cell death. We concluded that anti-CD45 and CD95 monoclonal antibodies modulates the effect of TNF-alpha on this cell line in vitro, and that these molecules participate in TNF-alpha cytotoxic response.