T细胞诱导的结肠炎中多形螺旋线虫感染对CD4^＋T细胞增殖的影响

目的 研究肠道多形螺旋线虫对T细胞诱导的小鼠结肠炎CD4^±T细胞增殖情况的影响。方法 用羟基荧光素二醋酸盐琥珀酰亚胺脂（CFSE）染色的卵清蛋白（OVA）特异性CD4＾±辅助性T细胞转入重度联合免疫缺陷（SCID）小鼠中，制作小鼠实验性肠炎模型。将实验模型小鼠分为多形螺旋线虫感染组和无感染组（每组n=5），观察多形螺旋线虫感染7d后小鼠结肠炎性反应的组织学变化；以流式细胞仪检测感染3、5、7d小鼠肠系膜淋巴结中CD4＾＋T细胞CFSE的阴性率，判定肠系膜淋巴结中CD4＾＋T细胞的增殖情况。结果 与无感染组比较，感染组小鼠第7天时有螺旋线虫感染结肠炎性反应明显加重，黏膜固有层细胞浸润增多，结肠上皮破损增加，病理评分明显升高（5．20±0．84比2．00±0．71，P〈0．05）。感染3、5、7d后，感染组小鼠肠系膜淋巴结中CD4±T细胞增殖均比无感染组明显增强，CFSE的阴性率升高3d：（7．03±1．61）％比（2．32±0．62）％，5d：（55．05±13．41）％比（29．10±2．23）％，7d：（76．97±1．89）％比（43．87±5．56）％，均P〈0．05]。结论 多形螺旋线虫感染在CD4＾＋T细胞诱导的小鼠实验性结肠炎的早期阶段促进了炎性反应的加重，可能与促进CD4＾＋T细胞的增殖有关。

Effects of Heligmosomoides polygyrus infection on CD4^＋ T cell proliferation in mice with T cell-induced cofifis

Objective To determine the effects of Heligmosomoides polygyrus infection on CD4^＋ T cell proliferation in mice with T cell-induced colitis. Methods The experimental colitis mice model was established via introduction of carboxyfluorescein diaccetate succinimidyl ester （CFSE）-stained ovalbumin- specific CD4^＋ helper T cell in severe combined immunodeficiency （SCID） mice. The mice were assigned into Heligmosomoides polygyrus infection group （n=5） and Heligmosomoides polygyrus non-infection group （n=5） for determining histological variation in colitis inflammation at day 7. The proportion of negative CFSE- stained CD4^＋ T cells and the proliferation of all CD4^＋ T cells at mesenteric lymph nodes were explored at days 3, 5 and 7 by using flow cytometry. Results As compared with non-infection group at day 7, Heligmosomoides polygyrus infection led to more serious colitis response. This was associated with increased inflammatory cell infiltration at laminar propria, strengthened epithelial injuries and elevated pathological scores （5.20±0.84 vs 2.00~0.71, P〈0.05）. There was a remarkably higher CD4^＋ T cell proliferation level in mesenteric lymph nodes in Heligmosomoides polygyrus infection group, and elevated proportion of CFSE negative-stained T cell was found at days 3, 5 and 7 as compared with non-infection groupday 3： （7.03± 1.61）% vs （2.32±0.62）%; day 5： （55.05±13.41）% vs （29.10±2.23）%; day 7： （76.97±1.89）% vs （43.87±5.56）%, all P〈0.05]. Conclusion Heligmosomoides polygyrus infection increases CD4^＋ T cell-induced inflammatory responses in mice with early-stage experimental colitis, which may be associated with the promotion of CD4^＋ T cell proliferation.