[Anergy, apoptosis and decreased MHC class I molecule expression of C57BL/6J mouse CD4+ T cells induced by SEB].
OBJECTIVE
To study the mechanism of peripheral T cell tolerance induced by superantigen Staphylococus aureus enterotoxin B (SAgSEB).


METHODS
Splenocytes from C57BL/6J (B6) mice were stimulated with SEB in-vitro. The proliferation of lymphocytes was determined by MTT colorimetry. The apoptosis of anergic T cells, the cells being in the S and G(0)-G(1) phase and MHC-I (H-2K(b)) expression of T cells were analyzed by flow cytometry (FCM). Apoptosis of anergic T cells was also demonstrated by DNA electrophoresis ladder.


RESULTS
SEB could induce strong proliferation of CD4+ T cells and the maximal percentage of CD4+ T cells in S phase appeared on 3rd day after SEB stimulation and then decreased, but the changes of percentage of CD4+ T cells in G(0)-G(1) phase was opposite to that in S phase. CD4+ T cells became anergy on 3rd day and apoptosis of anergic CD4+ T cells appeared on 5th day. Percentage of apoptosis cells increased gradually and could not be reversed by addition of anti-CD3 Ab and ConA. Expression of MHC-I (H-2K(b)) was marginally declined accompanied by CD4+ T cell anergy after SEB exposure.


CONCLUSIONS
SEB-induced tolerance may have relation to anergy and apoptosis of CD4+ T cells, and down-regulation of MHC-I molecules.
Liang
Feng
F
Hospital affiliated to Academy of Military Medical Science, Beijing 100039, China.
Yu
Cheng-ze
CZ
Chen
Yu
Y
Peng
Hong
H
D000818:Animals; D000942:Antigens, Bacterial / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D017635:Clonal Anergy / Q000187:drug effects*; D004768:Enterotoxins / Q000494:pharmacology*; D005260:Female; D006183:H-2 Antigens / Q000378:metabolism*; D008214:Lymphocytes / Q000166:cytology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000166:cytology; D013210:Staphylococcus
D000942:Antigens, Bacterial; D004768:Enterotoxins; D006183:H-2 Antigens; C078460:H-2K(sm1) antigen; C031818:enterotoxin B, staphylococcal