BCL-2 inhibits B7-induced MHC-unrestricted cytolysis mediated by a human NK cell line.
Recent work demonstrated that B7 expression by tumor cells can enhance antitumor immune responses. However, the B7 molecule is expressed abundantly on most non-Hodgkin's B-cell lymphomas and solid lymphoid tumors. How these tumor cells escape from immune surveillance mechanisms remains unclear. Lately, it has become clear that bcl-2 oncogene is overexpressed in a wide variety of human cancers and renders tumor cells more resistant to cytolytic T-cells (CTL) mediated cytotoxicity. We cloned B7 and B7/Bcl-2 transfectants and compared their susceptibilities to a human natural killer (NK) cell line and normal NK cells. The results demonstrate that Bcl-2 oncoprotein in tumor cells blocks B7-induced cytolysis mediated by a NK cell line and NK cells. Thus, they suggest that Bcl-2 oncoprotein plays a role in tumor avoidance of effective antitumor cytotoxicity.
Sun
L X
LX
Department of Late Effect Studies, Kyoto University, Japan.
Teshigawara
K
K
Uchida
A
A
D018122:B7-1 Antigen / Q000187:drug effects* / Q000494:pharmacology*; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects*; D008285:Major Histocompatibility Complex / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D018122:B7-1 Antigen; D011518:Proto-Oncogene Proteins