Bcl6 is required for the IL-4-mediated rescue of the B cells from apoptosis induced by IL-21.
IL-21 has a pro-apoptotic effect on freshly isolated B cells stimulated with LPS, and also induces Bcl6 expression in the activated B cells. However, a role for Bcl6 in the activated B cells is not known. When naive B cells from Bcl6-deficient mice were stimulated with LPS plus IL-21, those B cells died by apoptosis as wild-type B cells. Co-stimulation of those B cells with IL-4 partially rescued the wild-type B cells but not the Bcl6-deficient B cells from the IL-21-induced apoptosis. Bcl-2 was not up-regulated in both B cells stimulated with LPS plus IL-21 and IL-4. Bcl-X(L) and Bax were up-regulated in both B cells stimulated with LPS plus IL-4, and the co-stimulation with IL-21 did not modulate these up-regulations in wild-type B cells. However, the co-stimulation clearly suppressed the Bcl-X(L) up-regulation but not the Bax up-regulation in Bcl6-deficient B cells. Thus, Bcl6 is required for maintaining the Bcl-X(L) up-regulation in B cells stimulated with LPS plus IL-21 and IL-4, and the up-regulation may partially rescue the B cells from apoptosis induced by IL-21.
Tsuruoka
Nobuhide
N
Department of Developmental Genetics, Graduate School of Medicine, Chiba University, Chiba, Japan.
Arima
Masafumi
M
Arguni
Eggi
E
Saito
Thoru
T
Kitayama
Daisuke
D
Sakamoto
Akemi
A
Hatano
Masahiko
M
Tokuhisa
Takeshi
T
D000818:Animals; D000911:Antibodies, Monoclonal; D017209:Apoptosis; D001402:B-Lymphocytes / Q000276:immunology* / Q000502:physiology; D015153:Blotting, Western; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005434:Flow Cytometry; D015847:Interleukin-4 / Q000276:immunology / Q000378:metabolism*; D007378:Interleukins / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D051560:Proto-Oncogene Proteins c-bcl-6; D051020:bcl-X Protein / Q000378:metabolism; D000098546:Interleukin-21
D000911:Antibodies, Monoclonal; C490010:Bcl6 protein, mouse; D004268:DNA-Binding Proteins; D007378:Interleukins; D008070:Lipopolysaccharides; D051560:Proto-Oncogene Proteins c-bcl-6; D051020:bcl-X Protein; D015847:Interleukin-4; D000098546:Interleukin-21