八肽胆囊收缩素对经钥孔戚血蓝蛋白免疫小鼠T淋巴细胞亚群的影响

Cholecystokinin octapeptide modulates T-lymphocyte subsets in KLH-immunized mice

目的:探讨八肽胆囊收缩素(CCK-8)对经钥孔戚血蓝蛋白(KLH)免疫小鼠T淋巴细胞亚群的影响。方法:雌性BALB/c小鼠KLH免疫同时分别给予不同剂量CCK-8。流式细胞法检测小鼠外周血及脾细胞中CD4+、CD8+T细胞阳性百分率;RT-PCR法检测脾细胞中Th1型细胞因子IFN-γ、Th2型细胞因子IL-4 mRNA表达;ELISA法检测其培养上清中IFN-γ、IL-4水平;HE染色观察小鼠肺组织病理变化。结果:CCK-8下调KLH免疫小鼠外周血及脾细胞中上升的CD4+、CD8+T细胞阳性百分率,降低CD4+/CD8+比值;进一步提高其IFN-γ mRNA表达和培养上清中IFN-γ分泌量,同时下调上升的IL-4 mRNA表达和培养上清中IL-4分泌量;减轻KLH免疫所致小鼠肺部炎症。结论:CCK-8可调节适应性免疫应答,抑制T细胞尤其是CD4+T细胞活性;抑制Th2功能,提高Th1功能,因此可能在变态反应性疾病的发病和防治中具有一定作用。

AIM： To study the effects of cholecystokinin octapeptide （CCK- 8 ） on T- lymphocyte subsets in keyhole limpet haemocyanin （ KLH ） - immunized mice. METHODS ： Female BALB/c mice were immunized with KLH and injected with different dosages of CCK - 8 or saline simultaneously. Positive CD4^＋ and CD8^＋ T cells in peripheral blood or splenocytes were measured by flow cytometry. The production and mRNA level of Thl cytokine, IFN - γ and Th2 cytokine, IL - 4 in the splenocytes were evaluated by ELISA and RT - PCR, respectively. In addition, lung tissue sections were made with HE staining. RESULTS ： CCK - 8 downregulated the positive CD4^＋ and CD8 ^＋ T lymphocytes both in peripheral blood and in splenocytes in KLH - immunized mice, resulting in the reduction of CD4^＋/CD8^＋ ratio. CCK - 8 improved the production of IFN -γ, elevated IFN - γ gene transcription, whereas cut down the production of IL - 4, decreased IL-4 gene transcription. CCK- 8 lightened the pulmonary inflammation induced by KLH. CONCLUSION： CCK - 8 inhibits CD4 ^＋ T lymphocytes activation, Th2 cytokine mRNA expression and protein production in KLH - immunized mice, indicating that CCK-8 modulates adaptive immune response.