乳杆菌对原代淋巴细胞中Th1/Th2细胞平衡的影响

目的:分析7种乳杆菌对原代淋巴细胞增殖和细胞因子(CK)分泌的作用,进而探讨其对Th1/Th2细胞平衡的影响。方法:用不同种属、不同浓度的活的/热致死的乳杆菌体外作用于小鼠脾淋巴细胞培养60 h后,采用MTT比色法检测淋巴细胞的增殖效果。用ELISA法检测Th1型细胞因子(IL-12、IFN-γ)、Th2型细胞因子(IL-4、IL-10)和调节型细胞因子(TGF-β)的分泌量。结果:活的/热致死的乳杆菌单独作用,就能促进淋巴细胞体外增殖并表现出剂量依赖关系(P<0.05)。当菌的浓度为107集落形成单位(CFU)/mL(即细菌与细胞的比例为10∶1)时,热致死的发酵乳杆菌和嗜酸乳杆菌的免疫活性近似于活菌。而且,这两株热致死菌还可适当提高淋巴细胞分泌IL-12和IFN-γ,抑制IL-4、IL-10和TGF-β的分泌,使其IFN-γ/IL-4的比值(代表Th1/Th2细胞平衡)均显著高于刀豆蛋白A(ConA)对照组(P<0.05)。结论:乳杆菌可通过提高淋巴细胞的IFN-γ/IL-4分泌率来促进Th1优势状态的Th1/Th2细胞平衡,并具有菌株特异性。

Effect of lactobacilli on Th1/Th2 cells balance in primary lymphocytes

AIM:To analyse the effect of 7 Lactobacillus species on proliferation and cytokine production of primary lymphocytes,and explored the effect on the Th1/Th2 cells balance.METHODS: The mouse spleen cells were stimulated with active/heat-killed Lactobacillus strains at different species and concentrations.After be cultured with bacteria 60 hours,the proliferation of splenocytes were tested by MTT colorimetry,and IL-12,IFN-γ,IL-4,IL-10 and TGF-β were detected by ELISA.RESULTS:(1) Both alive and heat-killed Lactobacillus species could accelerate the proliferation of spleen cells in a dose-dependent manner(P<0.05),the immuneological activity of heat-killed L.fermentum and L.acidophilu were not inferior to the live strains,especially when treated at higher dose(107CFU/mL,bacteria: cell ratio of 10∶1).Furthermore,these two heat-killed bacterial strains suppressed IL-4,IL-10 and TGF-β production by stimulating IL-12 and IFN-γ production,and their IFN-γ/IL-4 value which represent the Th1/Th2 balance were higher than ConA control group significantly(P<0.05).CONCLUSION: The results indicate that Lactobacillus strains may differ in their respective ability to improve Th1/Th2 cells balance toward Th1 dominance via increasing the secretion ratio of IFN-γ/IL-4(Th1/Th2) by splenocytes.