共刺激因子B_7和LFA_3对人外周T细胞增殖和IL-2产生的效应

EFFECT OF COSTIMULATORS B7 AND LFA3 ON HUMAN T CELL PROLIFERATION AND IL-2 PRODUCTION

目的观察不同的共刺激因子在抗原提呈细胞存在的情况下，对人外周Ｔ细胞的增殖反应及ＩＬ┐２产生的作用。方法用选择性淘洗法纯化人外周Ｔ细胞，以葡萄球菌肠毒素Ａ（ＳＥＡ）为抗原，在体外培养的纯化Ｔ细胞中（１０６／ｍｌ）加入１０５／ｍｌ用ＨＬＡ┐ＤＲ４，Ｂ７，和ＬＦＡ３单独、双重或三重转染的人仓鼠卵巢细胞（ＣＨＯ）作为抗原提呈细胞（分别用ＣＨＯ┐ＤＲ４，ＣＨＯ┐ＤＲ４／ＬＦＡ３，ＣＨＯ┐ＤＲ４／Ｂ７，ＣＨＯ┐ＤＲ４／ＬＦＡ３／Ｂ７表示）。在体外培养后，用３Ｈ┐ＴｄＲ掺入法观察Ｔ细胞的增殖，用ＥＬＩＳＡ法测定培养上清液中的ＩＬ┐２含量。结果在无共刺激因子存在的情况下（Ｔ细胞＋ＣＨＯ┐ＤＲ４＋ＳＥＡ）Ｔ细胞增殖率低，上清液中几乎测不到ＩＬ┐２；在有ＬＦＡ３存在时（ＣＨＯ┐ＤＲ４／ＬＦＡ３）Ｔ细胞增殖率增加，但产生的ＩＬ┐２很少；Ｂ７（ＣＨＯ┐ＤＲ４／Ｂ７）明显提高Ｔ细胞的增殖率，并刺激产生大量ＩＬ┐２；ＬＦＡ３和Ｂ７同时存在的情况下（ＣＨＯ┐ＤＲ４／ＬＦＡ３／Ｂ７）Ｔ细胞增殖速率最高，并能协同增加ＩＬ┐２的产生。结论Ｔ细胞的活化除第一信号外还需有共刺激因子（第二信号）的存在，共刺激因子ＬＦＡ３和Ｂ７对Ｔ细胞活化的效应不同?

bjective:To observe the proliferation and IL2 production of human peripheral T lymphocytes, cultured with superantigen and antigen presenting cells expressing different cositmulators.Methods:Chinese hamster ovary (CHO) cells transfected with DR4(CHODR4),DR4 and LFA3 (CHODR4/LFA3),DR4 and B7 (CHODR4/B7) or DR4,LFA3 and B7(CHODR4/LFA3/B7) and superantigen staphylococcal enterotoxin A (SEA) were cultured with purified human T cells. After labeled with 3HTdR the T cell proliferation was expressed as cpm;the IL2 production in supernatants were measured with ELISA method. Results:Without costimulators (T cell+CHODR4+SEA) T cells showed low proliferation rate and little IL2 production; with costimulator LFA3(CHODR4/LFA3) T cell proliferation increased, but IL2 production was limited; with costimulator B7, T cell proliferation rate was markedly increased and so was IL2 production; with coexistence of LFA3 and B7,it showed the highest T cell proliferation rate and IL2 production.Conclusion:T cell activation requires coexistence of first signal and second signal (costimulator). Costimulators LFA3 and B7 demonstrate different effects on T cell activation indicating different receptors and pathway may be involved. Two costimulators also showed a synergetic effect on T cell activation.