[The identical effects of B7-1 and B7-2 on regulation of human IL-2 gene transcription factors NF-kappa B and AP-1].
To detect effects of B7 co-stimulation on cytokines, especially on IL-2 mRNA and transcription factors NF-kappa B and AP-1, antiB7-1 McAb, antiB7-2 McAb and C TLA-4 Ig were added into mixture lymphocyte reaction (MLR) system to block B7/C D28 signal transduction, IL-2 mRNA and IL-4 mRNA were determined by using competitive PCR and IFN-gamma mRNA by using semi-quantitative PCR. MHC class II molecules and B7 transfectants were used to stimulate CD28(+) T cell, effects of B7 on NF-kappa B and AP-1 were detected by DNA-protein binding assay. The results showed that IL-2, IL-4 and IFN-gamma mRNA were significantly lower when blockade of B7-2 in MLR than blockade of B7-1. Synergistic effects could be seen with combination of two or three antibodies. One to six hours after MLR, tDR7 alone induced NF-kappa B binding activity; cotransfecting B7 no significantly difference at early time point. After 6 hours, induction of tDR7 was decreased whereas B7 prolonged the induction of NF-kappa B till 72 hours. tDR7 alone also upregulated AP-1 binding activity, on the contrary to NF-kappa B, co-transfecting B7-1 and B7-2 decreased AP-1 binding activity within 24 hours. But during 48 - 72 hours, B7 also prolonged the AP-1 binding activity. It is concluded that after MLR, B 7 increased IL-2 secretion by decreasing the degradation of IL-2 mRNA and upregulating IL-2 transcription factors. B7 also induced several kinds of cytokines secretion. Effects of B7-1 and B7-2 had no significant difference on transcription factors. It is suggested that the different functions between B7-1 and B7-2 maybe related to the difference of cell expression and kinetics. To study the molecular mechanism of B7 mediated T cell immune tolerance can help us to design a better clinic schema to prevent transplantation rejection and GVHD.
Ke
Xiao-Yan
XY
Department of Hematology, The Third Hospital, Peking University, Beijing 100083, China. xiaoyank@yahoo.com
Gribben
John
J
Wang
Jing
J
Wang
De-Bing
DB
D016475:3T3 Cells; D000818:Animals; D015703:Antigens, CD / Q000502:physiology*; D018122:B7-1 Antigen / Q000502:physiology*; D051940:B7-2 Antigen; D018106:CD28 Antigens / Q000502:physiology; D005786:Gene Expression Regulation; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics; D007376:Interleukin-2 / Q000235:genetics*; D015847:Interleukin-4 / Q000235:genetics; D007959:Lymphocyte Culture Test, Mixed; D008562:Membrane Glycoproteins / Q000502:physiology*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D018808:Transcription Factor AP-1 / Q000378:metabolism*
D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018106:CD28 Antigens; C497964:CD86 protein, human; C497965:Cd86 protein, mouse; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D015847:Interleukin-4; D007371:Interferon-gamma