[Effect of CD28 costimulator on T cell receptor(TCR)-induced apoptosis of thymocytes].
OBJECTIVE
To analyze apoptosis and its degree of thymocytes at early and intermediate phases induced by anti-TCRalphabeta mAb or anti-TCRalphabeta mAb+anti-CD28 mAb stimuli, and to analyze the influence of CD28 costimulator on TCR-induced apoptosis of thymocyte subsets.


METHODS
Thymocytes were freshly prepared and were cultured for 20 h in the presence of anti-TCRalphabeta mAb+anti-CD28 mAb or anti-TCRalphabeta mAb along, The cultured cells were stained with fluorescein labelled Annexin V, PI, anti-CD4 mAb and anti-CD8 mAb, then color reagents. The apoptotic cells were analyzed by FACS.


RESULTS
Compared with the spontaneous apoptosis of thymocytes cultured in medium alone, CD28 costimulator markedly enhanced the number of thymocyte apoptosis at early and intermediate phases; under the action of double signaling stimulators, the apoptosis of CD4(+) CD8(+)(DP) thymocytes were substantially increased, and the expression of CD28 were also upregulated on these apoptotic DP cells.


CONCLUSIONS
Influence of CD28 costimulator on TCR-induced apoptosis of thymocyte subsets might be related to thymocyte's mature degree. Double signaling may induce apoptosis of DP thymocytes.
Li
Hong-mei
HM
Department of Immunology, Peking University Health Science Center, Beijing 100083, China.
Zhang
Hua-gang
HG
Wang
Hong-cheng
HC
Qian
Xiao-ping
XP
Kong
Xian-tao
XT
Chen
Wei-feng
WF
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D017209:Apoptosis; D018106:CD28 Antigens / Q000276:immunology* / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology; D002478:Cells, Cultured; D053938:DNA Fragmentation; D051379:Mice; D008807:Mice, Inbred BALB C; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism
D000911:Antibodies, Monoclonal; D018106:CD28 Antigens; D016693:Receptors, Antigen, T-Cell, alpha-beta