THE EXPRESSION OF GENES MODULATING PROGRAMMED CELL-DEATH IN NORMAL HUMAN POLYMORPHONUCLEAR NEUTROPHILS

Normal human polymorphonuclear neutrophils (PMN) have a short life and die in progression via apoptosis. In order to understand the molecula r basis of PMN apoptosis, the expression of apoptosis-related (Fas, Fa s-ligand, p53, and c-myc) and survival-related (bcl-2) genes was detec ted by flow cytometry, Western blot and reverse transcription-assisted polymerase chain reaction (RT-PCR). We found that Fas and Fas-ligand (Fast) were expressed on the sur-face of most of the cells. However, t he disappearance of Fast was much faster than Fas after 24h incubation . p53 and bcl-2 were also expressed in the cytoplasm of most of the ce lls. In contrast, the expression of c-myc was negligible in PMN. The a ddition of monoclonal anti-human Fas antibody (25 mu g/ml) to PMN susp ension enhanced whereas anti-FasL antibody (25 mu g/ml) suppressed PMN apoptosis in 48h incubation. These results suggest that the activatio n of Fas pathway induced by Fas-FasL interaction among PMNs is one of the mechanisms for spontaneous PMN apoptosis. Lack of proto-oncoprotei n c-myc expression in PMN is responsible for their non-proliferative p roperty and may aggravate the spontaneous apoptosis of the cells. (C) 1997 Academic Press.