To study relationships between glycosylation and cell survival we used a human alpha-mannosidase, 6A8, recently discovered in our laboratory. We found that glycosylation of BJAB cells was modified when cells were transduced with a fragment of antisense 6A8 cDNA, which resulted in an inhibition of 6A8 alpha-mannosidase expression. In comparison to wild type, mock- or sense 6A8-tansduced cells, the antisense 6A8-transduced cells showed increased cell death in culture. The dying cells were characterized by cell and nucleus swelling, membrane blebbing, organelle dilation and membrane breaking at the blebbing sites. They did not have apoptotic bodies. Annexin-V staining and DNA fragmentation assays also showed no evidence of apoptosis in these cells. This data implied that BJAB cells underwent an oncosis-like cell death upon transduction with a fragment of antisense 6A8 cDNA, which inhibited 6A8 alpha-mannosidase expression and therefore modified glycosylation of proteins shown by Con A binding test. These data imply that 6A8 alpha-mannosidase plays an important role in preventing oncosis-like death in BJAB cells. The possible mechanism of cell death by oncosis was discussed.