CCK-8对LPS作用下巨噬细胞B7.1和B7.2表达及其协同刺激功能的影响

Effect of CCK-8 on B7.1 and B7.2 expressions and costimulatory activity of LPS-activated murine macrophages

目的探讨八肽胆囊收缩素（CCK-8）对LPS活化的巨噬细胞B7．1和B7．2表达及其协同刺激功能的影响。方法用CCK-8（10^-12～10^-6）mol·L^-1和（或）脂多糖（LPS）孵育小鼠腹腔巨噬细胞，采用流式细胞术分析细胞表面B7．1和B7．2含量的变化，用免疫磁珠从小鼠脾细胞分离CD4^＋T细胞，按4：1数量比与腹腔巨噬细胞[预先用LPS、CCK-8和（或）抗B7．1抗体、抗B7．2抗体、CCK1R拮抗剂CR1409、CCK2R拮抗剂CR2945孵育24h]共同体外培养，同时加入ConA5mg·L^-1，采用^3H参入法测定CD4^＋T细胞增殖反映巨噬细胞的协同刺激活性。结果CCK-8可以下调LPS诱导的巨噬细胞的B7．1和B7．2表达，抑制LPS活化的巨噬细胞的协同刺激活性。CCK-8的作用呈剂量依赖性，最大效应剂量在（10^-7-10^-9）mol·L^-1之间。CR1409及CR2945均能逆转CCK-8的上述作用，且CR1409的作用较CR2945更明显。抗B7．1抗体和抗B7．2抗体可减轻LPS活化的巨噬细胞协同刺激活性。结论CCK-8通过下调LPS诱导的巨噬细胞B7．1和B7．2表达而抑制其协同刺激活性，该作用由CCK1R及CCK2R介导，其中CCK1R起主要介导作用。

Aim To investigate in vitro effects of CCK- 8 on the expressions of B7.1 and BT. 2 and the costimulatory activity for T lymphocytes in LPS-activated macrophages. Methods Mouse peritoneal macrophages were isolated and incubated with LPS and/or CCK- 8 （ 10^-12 - 10^-6 ） mol · L^-1 for indicated times. The B7.1 and B7.2 expressions of murine peritoneal macrophages were analyzed by flow cytometry. CD4^＋ T ceils were isolated from mouse spleen by using immunomagnetic beads, and cultured with 1/4 numbers of macrophages which were pretreated with LPS, CCK-8 and/or anti-B7.1 antibody, anti-B7.2 antibody, CCK1R antagonist CR1409, CCK2R antagonist CR2945 for 24 h. ConA was added into the culture medium to stimulate CD4 ^＋ T cell proliferation. The proliferation was determined by measuring [ 3H ]-TdR incorporation in a [3-scintillation counter. Results LPSinduced B7.1 and B7.2 expressions and costimulatory activity of peritoneal macrophages were inhibited by CCK-8 in a dose-dependent manner, with the maximal effects occurred at the concentrations from 10-7 mol ~ L^-1 to 10-9 mol · L^-1. Both CR1409 and CR2945 reversed the effect of CCK-8 on costimulation, and the role of CR1409 was more significant. Anti-B7.1 antibody and anti-B7.2 antibody inhibited the modulatory role of LPS on costimulatory activity. Conclusion CCK-8 inhibited LPS-induced macrophage costimulatory activity by down-regulating B7.1 and B7.2 expressions, which was mediated by CCK1R and CCK2R. CCK1R might be the major receptor responsible for the modulation of CCK-8 on costimulation.