Induction of bcl-x by CD40 engagement rescues sIg-induced apoptosis in murine B cells.
CD40L, a membrane protein of activated T cells, interacts with the B cell receptor CD40. This interaction has been implicated in the rescue of germinal center B cells from apoptosis and in the rescue of WEHI-231 B lymphoma cells from sIg-induced apoptosis. In this report, we have demonstrated that the signal mediated by CD40L acts upon bcl-x, a bcl-2 homologue. bcl-x expression is strongly enhanced by CD40 receptor engagement, while there is little or no induction by sIg cross-linking. The expression of bax and bcl-2 is not significantly affected by either CD40L or sIg cross-linking. Antisense but not sense phosphorothioate oligonucleotide for bcl-x can partially block this CD40-mediated apoptotic rescue. This result suggests that the up-regulation of bcl-x by CD40L plays an important role in CD40-mediated apoptotic rescue in murine B cells.
Wang
Z
Z
Department of Medicine, Boston University Medical Center, MA 02118, USA.
Karras
J G
JG
Howard
R G
RG
Rothstein
T L
TL
D000818:Animals; D017209:Apoptosis / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D019013:CD40 Antigens / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic / Q000276:immunology*; D016393:Lymphoma, B-Cell / Q000235:genetics / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000276:immunology; D019253:Proto-Oncogene Proteins c-bcl-2; D011947:Receptors, Antigen, B-Cell / Q000235:genetics / Q000502:physiology*; D014407:Tumor Cells, Cultured; D051020:bcl-X Protein
C494812:Bcl2l1 protein, mouse; D019013:CD40 Antigens; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011947:Receptors, Antigen, B-Cell; D051020:bcl-X Protein