Stat1 implication in the immune response to superantigens in vivo.
We analyzed the activation and changes in the protein level of STAT1 as a consequence of in vivo treatment with superantigens. Ninety minutes after i.p. injection of the staphylococcal enterotoxin B (SEB), a complex containing STAT1 that was able to specifically bind to DNA containing GAS-like sequences was activated in mouse splenocytes. This complex had the same characteristics as that induced by IFN-gamma in several in vitro systems. Activation of the complex was inhibited by cyclosporin A, and Abs against IFN-gamma severely decreased the amount of complex detected. When splenocytes were analyzed 24 h after SEB treatment, a high increase in the amount of the STAT1 isoforms, STAT91 and STAT84, was observed by Western analysis, but binding to GAS-like sequences was clearly decreased when compared with analysis at 90 min. Nevertheless, when SEB was injected a second time 24 h after the first injection, the binding of STAT1 to GAS-like sequences had risen again. This approach corroborates the implication of IFN-gamma in the response to superantigens in vivo and shows the relevance of analysis of transcription factors in defining the molecular events involved in the immune response.
Gimeno
R
R
Department of Immunology, Sant Pau Hospital, Autonomous University of Barcelona, Spain.
Codony-Servat
J
J
Plana
M
M
Rodriguez-Sanchez
J L
JL
Juarez
C
C
D000818:Animals; D001483:Base Sequence; D016572:Cyclosporine / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004768:Enterotoxins / Q000276:immunology*; D005260:Female; D005786:Gene Expression Regulation; D007075:Immunoglobulin M / Q000378:metabolism; D007166:Immunosuppressive Agents / Q000494:pharmacology; D007371:Interferon-gamma / Q000502:physiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism; D050794:STAT1 Transcription Factor; D015398:Signal Transduction; D013154:Spleen / Q000166:cytology; D018089:Superantigens / Q000276:immunology*; D015534:Trans-Activators / Q000378:metabolism*
D016207:Cytokines; D004268:DNA-Binding Proteins; D004768:Enterotoxins; D007075:Immunoglobulin M; D007166:Immunosuppressive Agents; D012333:RNA, Messenger; D011947:Receptors, Antigen, B-Cell; D050794:STAT1 Transcription Factor; C494080:Stat1 protein, mouse; D018089:Superantigens; D015534:Trans-Activators; C031818:enterotoxin B, staphylococcal; D007371:Interferon-gamma; D016572:Cyclosporine