双歧杆菌脂磷壁酸对化疗荷瘤小鼠免疫功能的影响

目的探讨双歧杆菌脂磷壁酸对5-氟尿嘧啶（5-FU）化疗肝癌H22荷瘤小鼠免疫的影响及其作用机制。方法双歧杆菌脂磷壁酸处理5-Fu化疗的H纶荷瘤Balb／c小鼠，MTT法检测NK细胞和CTL细胞杀伤活性；采用流式细胞仪检测荷瘤小鼠脾细胞中T亚群比例；用RT-PCR和Western Not方法分别检测荷瘤小鼠肿瘤组织Foxp3和TIM-3mRNA及蛋白的表达变化。结果荷瘤小鼠脾细胞中CD4^＋ CD25^＋Tmg比例高，并存在Foxp3和TIM-3 mRNA及蛋白的高表达，经双歧杆菌LTA和5．Fu处理后CD4^＋CD25^＋Tmg比例下降，Foxp3和TIM-3mRNA及蛋白表达水平也均呈下调趋势，但5-FU单独处理后的荷瘤小鼠脾细胞中CD4^＋细胞比例也减少，NK细胞和CTL杀伤率均降低，而双歧杆菌LTA处理后CD4^＋细胞比例，NK细胞和CTL杀伤率却明显增加。二者联合处理也能增加CD^＋细胞比例及NK细胞和CTL杀伤率。结论双歧杆菌脂磷壁酸联合5-FU可通过增强NK细胞和CTL杀伤能力，同时抑制TIM-3／TIM-3L途径，降低CD4^＋CD25^＋Tmg的免疫抑制活性，增强机体细胞免疫来提高化疗抗肿瘤效果，减轻化疗副作用，增强宿主对化疗的耐受性，从而提高抗肿瘤作用。

Effect of lipoteichoic acid of Bifidobacterium on immune function of tumor-bearing mice with chemotherapy

Objective To investigate the immunity effects and mechanism of lipoteichoie acid （LTA） of Bifidobacterium on the mice bearing inoculated H22 cells treated with 5-FU. Method Tumor-bearing mice were treated with 5-FU alone, LTA alone or LTA in combination with 5-FU. MTT assay was used to evaluate killing activity of NK cells and CTL cells. FCM was used to detect T subgroup ratio of spleen cells of tumor-bearing mice. Changes of mRNA and protein expression of Foxp3 and TIM-3 in tumor-bearing mice tumor tissue were detected by RT-PCR and Western blot. Result Spleen cells of tumor-bearing mice had high CD4^＋ CD25^＋ Tmg ratio and high mRNA and protein expression of Foxp3 and TIM-3. After treatment by LTA and 5-FU, the CD4^＋ CD25^＋ Tmg ratio degraded, with down regulation of mRNA and protein expression of Foxp3 and TIM-3. The CD4^＋T cells and the killing activity of NK and CTL cells decreaed after treated with 5- FU alone,while significantly increased by LTA treatment. LTA in combination with 5-FU could also enhance the ratio of CD4^＋ T cells and the killing activity of NK cells and CTL cells. Conclusion LTA of Bifidobacterium in combination with 5-FU could enhance anti-tumor effect and relieve side effect of chemotherapy by enhancing the killing capability of NK cells and CTL cells, inhibiting TIM-3/TIM-3 L pathway, cutting down immunosuppressive activity of CD4^＋~ CD25^＋ Tmg and enhancing cell-mediated immunity.