中国恒河猴感染SIV后T淋巴细胞免疫活化及其肠粘膜归巢受体的表达

目的 研究中国恒河猴感染SIV后T淋巴细胞免疫活化及其肠粘膜归巢受体表达的情况。方法 选用12只健康中国恒河猴,分为正常动物组(对照组)4只,模型感染组(模型组)8只,静脉接种SIVmac239病毒株,分别于感染前、感染后1周、2周、3周、4周、8周、11周、14周采用免疫组化技术检测猴模型回肠组织中的肠淋巴归巢相关受体(intestinal lymphatic homing receptor) a47、CCR9、aE7、CD62L及肠淋巴组织活化分子CD69的表达; real-time PCR检测病毒载量,流式细胞仪检测T淋巴细胞亚群、CD4T淋巴细胞活化水平、外周血肠淋巴归巢受体表达水平; ELISA检测血清CD62L。结果 中国恒河猴感染SIV两周后,模型组和对照组的血液学指标(WBC、 LYM%、LYM、RBC)均在正常范围值里,两组差异无统计学意义(P>0.05)。模型组CD4/CD8低于对照组,CD8计数高于对照组(P<0.01)。模型组病毒载量显著高于对照组(P<0.01)。AIDS猴感染模型在感染2周起,CD4百分比开始逐渐下降,于感染8周后下降明显(P<0.05)。感染11周后(亚急性期),CD4计数在下降明显(P<0.05)。AIDS猴感染模型在感染1周(急性期)开始,CD4⁺HLA-DR⁺出现一过性上升,随即下降,但感染14周时又骤然升高。CD4⁺CD45⁺HLA-DR⁺和CD3⁺HLA-DR⁺在感染1周时呈现波动上升趋势,随后逐渐下降。血浆中CD62L在感染1周时开始逐渐上升,并在感染到第8周左右到达一个高峰期,随后开始出现下降(P<0.01)。中国恒河猴感染SIV后,肠淋巴归巢受体 47、CCR9、E7的表达升高,L-选择素的表达降低,同时E7、CCR9在外周血CD4⁺T细胞上的表达及肠道淋巴组织免疫活化分子CD69的表达升高。结论 中国恒河猴感染SIV后,效应性T淋巴细胞的肠淋巴归巢增强,初始T淋巴细胞肠淋巴归巢受到抑制,肠粘膜免疫系统出现过度活化现象。

Immune activation of T lymphocytes and expression of intestinal homing receptors in Chinese rhesus macaque model infected with SIV

Objective To study the immune activation of T lymphocytes and expression of intestinal homing receptors in Chinese rhesus macaque model infected with simian immunodeficiency virus (SIV). Methods Twelve healthy Chinese rhesus macaque were divided into two groups: a SIV-infected group (n=8) and a normal control group (n=4). The animals in the SIV-infected group were inoculated with SIVmac239 virus strain. Before and 1, 2, 3, 4, 8, 11, 14 weeks after the inoculation, the tests, including a47, CCR9, aE7 and CD62L of intestinal lymphatic homing receptors and CD69 of activated molecules were performed in the ileum tissue of SIV model with immunohistochemistry technique; the viral loads were detected by real-time PCR; the T lymphocyte subsets, CD4 T lymphocyte activation levels, and peripheral lymphocyte homing receptor expression levels in blood and intestines were detected with flow cytometry; serum CD62L was detected by ELISA. Results Two weeks after the infection of the Chinese rhesus macaque monkeys with SIV, the hematological indexes of both the model group and the control group were in the normal range, and there was no statistical difference between the two groups (P>0.05); CD4/CD8 rate of the model group was significantly lower than that in the control group, while CD8 count was significantly higher than the control group (P<0.01); the viral load of the model group was significantly higher than that in the control group (P<0.01). The protein level began to decline gradually two weeks after the infection, and decreased significantly eight weeks after the infection (P<0.05). Eleven weeks after the infection (subacute phase), CD4 count decreased significantly. CD4⁺HLA-DR⁺ appeared a transient increase at one week after the infection in model AIDS infected monkeys (acute phase), then dropped, but the infection increased suddenly at 14 weeks. CD4⁺CD45⁺HLA-DR⁺ and CD3⁺HLA-DR⁺ showed a fluctuating upward trend at one week after the infection, then decreased gradually. The plasma CD62L began to rise gradually at one week after the infection and reached a peak at eight weeks, and then began to decline. The intestinal lymphatic homing receptor 47, CCR9, E7 expressions were promoted, and L-selectin was decreased in the intestinal lymph nodes; E7 , CD69 and CCR9 expressions were promoted in peripheral blood CD4+T cells. The initial T lymphocytes of intestinal lymphatic homing were inhibited to promote the effector T lymphocyte homing of intestinal lymph. Conclusion After the Chinese rhesus macaque monkeys are infected with SIV, the intestinal lymphatic homing receptor expressions are promoted, the initial T lymphocytes of intestinal lymphatic homing are inhibited, and there is an excessive activation of intestinal mucosal immune system.