Apoptotic Phenomenon of Immune Effector Cells in Autoimmune Nzb X Nzw F1 Mice

Abstract

Programmed cell death (apoptosis) is a process involved in the development of various tissues and suggested to be critical in the elimination of self-reactive immature T and B lymphocytes when they first encounter self antigens. To investigate further the role of apoptosis in the pathogenesis of autoimmune disease, the apoptotic phenomena of spleen cells and peritoneal cells of NZB/W F1 mice or nonautoimmune BALB/c mice were studied. Spleen cells and peritoneal cells were isolated and analyzed for their apoptotic phenomenon with the method of DNA staining. The data showed: 1) freshly isolated-spleen cells from BALB/c and NZB/W F1 mice showed little apoptosis as assessed by quantitative DNA flow cytometry, and had a significant increase with age (p < 0.001); 2) and data also showed that spleen cells of NZB/W F1 have higher spontaneous apoptotic rate than those of BALB/c mice (p < 0.05); 3) the apoptotic rate of dexamethasone (DEX)-treated spleen cells was lower in NZB/W F1 mice compared to that of nonautoimmune mice; 4) peritoneal cells showed little apoptosis when cells were freshly isolated and also had a striking increase with age ( p < 0.05); 5) the apoptotic rate of DEX-treated peritoneal cells increased dramatically with age in BALB/c (p < 0.05), but not in NZB/W F1 mice. Our data showed quite clearly that splenic cells are much different from peritoneal cells according to their apoptotic responses. Furthermore, the apoptotic phenomenon of immune effector cells was also different between those of autoimmune and normal mice.