Phosphorylation of Bcl-2 and mitochondrial changes are associated with apoptosis of lymphoblastoid cells induced by normal immunoglobulin G.
Normal human immunoglobulin G induces apoptosis in human lymphoblastoid cells which involves antibody-mediated Fas ligation and the activation of caspases. Here, we show that Bcl-2 is phosphorylated on serine upon treatment of CEM T cells with normal IgG and that the overexpression of Bcl-2 in stable transfectants of CEM T cells prevents IgG-induced cell death. Treatment of CEM cells with normal IgG also results in a reduction in mitochondrial transmembrane potential and in the release of cytochrome c (Cyt c) into cytosol. The findings are concordant with earlier observations that apoptosis induced by IgG is associated with the activation of caspases. Our results demonstrate that Bcl-2 controls apoptosis induced by normal IgG and support a central role for Bcl-2 and mitochondria in antibody-mediated selection of lymphocyte repertoires.
Sooryanarayana
INSERM U430 and Université Pierre et Marie Curie, Hôpital Broussais, Paris, France.
Prasad
N
N
Bonnin
E
E
Pashov
A
A
Ben Jilani
K
K
Ameisen
J C
JC
Kazatchkine
M D
MD
Kaveri
S V
SV
D017209:Apoptosis / Q000187:drug effects; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology / Q000494:pharmacology*; D007223:Infant; D008214:Lymphocytes / Q000378:metabolism* / Q000473:pathology* / Q000648:ultrastructure; D008928:Mitochondria / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*
D007074:Immunoglobulin G; D019253:Proto-Oncogene Proteins c-bcl-2