已免疫CD4＋记忆性T淋巴细胞介导HBV转基因小鼠抗HBsAg免疫应答的研究

A study of immune response to HBsAg mediated by CD4＋ memory T lymphocytes in immunized HBV transgenlc mice

目的研究已免疫CD4＋记忆性T淋巴细胞介导HBV转基因小鼠（Tg小鼠）抗HBsAg免疫应答的作用机制。方法通过免疫磁珠分选分离、收集乙型肝炎疫苗成功免疫的C57BL／6小鼠外周血CD4＋Tin淋巴细胞，再通过尾静脉注射过继免疫Tg小鼠，分别于过继免疫后4、8周采小鼠外周血，通过酶联免疫吸附法检测HBsAg、抗-HBs、干扰素γ（IFNγ）、白细胞介素2（IL-2），同时通过免疫组织化学法检测小鼠肝脏的HBsAg。计量资料用t检验，计数资料用疋。检验。结果与对照组相比，试验组Tg小鼠HBsAg滴度均明显降低[（243．5±12．4）ng／mt对比0ng／mt]，t=3．939，P=0．011，差异有统计学意义；抗-HBs水平[（0ng／ml对比（530．7±17．5）ng／ml]、IFNγ[（12．25±2．9）pg／ml对比（38．8±6．8）pg／ml]和IL-2水平[（11．3±3．5）pg／ml对比（82．3±9．2）pg／ml]，均明显升高，t值分别为4．414、2．785、2．993，尸值分别为0．0069、0．0496、0．0402，差异均有统计学意义。结论已免疫CD4＋记忆性T淋巴细胞介导HBV转基因小鼠，可通过提高IFNv和IL-2细胞因子水平，增强体液和细胞免疫，从而介导Tg小鼠体内HBsAg的清除。

Objective To investigate the mechanism of immune response to HBsAg mediated by CD4＋ memory T lymphocytes in immunized HBV transgenic （Tg） mice. Methods Peripheral CD4＋ memory T lymphocytes were isolated and collected by magnetic bead sorting from C57BL/6 mice successfully immunized by hepatitis B vaccine. Adoptive immunization was performed for Tg mice by caudal vein injection, and the peripheral blood was collected at 4 and 8 weeks after adoptive immunization. Enzymelinked immunosorbent assay was used to measure the levels of HBsAg, anti-HBs, interferon-γ （IFNT）, and interleukin-2 （IL-2）, and immunohistochemistry was used to measure the level of HBsAg in the liver. The t-test was used for comparison of continuous data, and the chi-square test was used for comparison of categorical data. Results Compared with the control group, the experimental group had a significant reduction in HBsAg titer[（243.5＋12.4） ng/ml vs 0 ng/ml, t = 3.939, P = 0.011] and significant increases in the levels of anti-HBs [0 ng/ml vs （530.7±17.5） ng/ml, t = 4.414, P = 0.006 9], IFN7 [（12.25±2.9） pg/ml vs （38.8±6.8） pg/ml, t = 2.785, P = 0.049 6], and IL-2 [（11.3±3.5） pg/ml vs （82.3±9.2） pg/ml, t = 2.993, P = 0.040 2].Conclusion As for immune response to HBsAg mediated by CD4＋ memory T lymphocytes in immunized HBV Tg mice, increases in the levels of IFNγ and IL-2 help to enhance humoral and cellular immunity and mediate the clearance of HBsAg in Tg mice.