【摘要】 目的 研究小鼠免疫接种基因重组乙型肝炎表面抗原疫苗(recombinant HBV surface vaccine,rHBs)产生的特异性细胞免疫反应。方法 40只BALB/c小鼠随机分为0.65、1.25、2.5、5μg 4组,腹腔分别接种0.65、1.25、2.5、5μg的rHBs 1次或2次。初次免疫后4周或加强免疫后2周分离小鼠脾T淋巴细胞,分别进行脾T淋巴细胞释放IFNr、IL-2及细胞毒T淋巴细胞(cytotoxic T lymphocyte,CTL)实验;脾T淋巴细胞释放实验:用10g/ml rHBs刺激脾T淋巴细胞,3天后用ELISA方法检测培养液中IL-2及IFNr的浓度。CTL实验,脾T淋巴细胞用特异性多肽刺激,用51Cr释放实验检测CTL。结果 只接受单次免疫的0.65、1.25、2.5、5μg组小鼠脾T淋巴细胞释放的IL-2分别为5.48±8.88、9.28±6.98、28.53±14.32、64.69±20.88pg/ml,释放的IFNr分别为8.22±8.61、9.89±9.34、20.27±15.50、30.77±22.12pg/ml。接受加强免疫的0.65、1.25、2.5、5μg组小鼠脾T淋巴细胞释放的IL-2分别为5.75±5.04、102.53±67.52、177.13±91.12、332.10±124.31pg/ml,释放的IFNr分别为3.63±4.42、28.33±13.04、59.66±25.75、80.73±19.30pg/ml。CTL反应的靶细胞自然释放率为28.76%±13.45%;加强免疫组小鼠0.65、1.25、2.5、5组小鼠,CTL特异性释放率分别为(42.36±19.32)%、(91.21±22.97)%、(69.25±24.13)%、(51.49±21.661)%;只接受1次免疫接种的小鼠,其脾淋巴细胞特异性CTL特异性释放率分别为(32.27±15.35)%、(56.28±24.35)%、(44.34±18.65)%、(40.76±56)%。结论 小鼠接种rHBs后,脾T淋巴细胞产生特异性CTL反应,并特异性分泌IL-2、IFNr,反应强度与是否加强免疫及接种的剂量密切相关。
【关键词】 HBV疫苗;免疫接种;小鼠;脾T淋巴细胞;IL-2;IFNr;CTL反应
The cellular immune response to recombinant HBV vaccine
【Abstract】 Objective Hepatitis B virus(HBV) surface vaccine(rHBs) specific MHC class I-restricted cytotoxic T lymphocytes (CTL) responses induced by immunization with rHBs in murine were assayed.Methods BALB/c(H-2d) murine were injected intraperitoneal(i.p.)with rHBs at doses ranging from 0-6 μg and boosted after 2 weeks. 4 weeks after the last immunization,to measure the IL-2 and IFNr,spleen lymphocytes were harvested and restimulated with rHBs in experimental group or with PBS as control,4 weeks later after the last vaccination. For CTL assay,spleen cells were restimulated in vitro with specific peptides,which represents a Ld-restricted CTL epitope of the S-protein in H-2d BALB/c murine. The specific cytotoxic reactivity of in vivo primed and in vitro restimulated cells was tested against P815 cells impulsed with specific peptides and labeled with 51Cr. 4 hours release assay of 51Cr was performed. Results 2 weeks after primary vaccination,the IL-2 were 5.48±8.88,9.28±6.98,28.53±14.32,64.69±20.88 respectively;IFNr were 8.22±8.61,9.89±9.34,20.27±15.50,30.77±22.12 separately. 2 weeks after boost vaccination,the IL-2 were 5.75±5.04,102.53±67.52,177.13±91.12,332.10±124.31 separately;IFNr were 3.63±4.42,28.33±13.04,59.66±25.75,80.73±19.30 separately. For CTL assay,the percentages of specific release of the mouse spleen lymphocyte in group 0.65 μg、1.25 μg、2.5 μg、5 μg were 42.36%±19.32%、91.21%±22.97%、69.25%±24.13%、51.49%±21.661%,respectively. For the mouse receive only priming vaccination,the percentages of specific release of the mouse spleen lymphocyte in group 0.65、1.25、2.5、5 were 32.27%±15.35%、56.28%±24.35%、44.34%±18.65%、40.76±56% respectively. Conclusion Injection with rHBs efficiently prime MHC-I restricted CTL response to the S-HBsAg in BALB/c(H-2d) murine,which was enhanced by boosting injection.
【Key words】 rHBs;murine;immunization;spleen T lymphocytes;IL-2;IFNr;CTL reaction
乙型肝炎病毒(hepatitis B virus,HBV)感染是一种严重危害人体健康的常见疾病,全世界有3.5亿HBV感染者。接种基因重组HBV表面抗原疫苗(recombinant HBV surface vaccine,rHBs)能产生保护性抗体,已广泛用于预防HBV感染。然而抗HBV特异性细胞免疫反应决定HBV感染的预后,细胞免疫反应不足,即使抗HBV特异性体液免疫反应较强,也常导致HBV持续感染,清除体内已有的HBV、治疗HBV感染需要较强的抗HBV特异性细胞免疫反应。
接种rHBs能否产生HBV特异性细胞免疫反应,能否用于治疗HBV感染还不十分清楚。笔者给小鼠接种rHBs,研究其脾T淋巴细胞能否产生特异性CTL反应,能否释放特异性细胞因子,对接种rHBs产生的特异性细胞免疫反应进行定量及功能分析。
1 资料与方法
1.1 试剂 rHBs含HBV表面抗原preS2/S,酵母基因重组产品,Merck公司生产。合成的特异性多肽IPQSLDSWWTSL(S28-39),为H-2d BALB/c小鼠Ld限制rHBs-CTL表位(Saibaisheng公司生产),以50 mg/ml浓度溶解在70%乙腈或0.1% DMSO储存液中,临用前以培养液稀释。Na251CrO4购自中国同位素公司。IL-2及r-IFN检测试剂盒:U-CyTech公司。
1.2 实验动物 BALB/c小鼠。6~10周龄,SPF级。
1.3 方法
1.3.1 BALB/c小鼠免疫接种 小鼠按以下分组,腹腔内分别接种不同剂量的rHBs,一半小鼠2周后加强免疫接种1次,另一半只接种1次:0.65组(10只),接种0.65μg的rHBs;1.25组(10只),接种1.25μg的rHBs;2.5组(10只),接种2.5μg的rHBs;5组(10只),接种5μg的rHBs。
1.3.2 小鼠脾T淋巴细胞分离培养 接种后2周,氯仿麻醉小鼠,脱颈处死小鼠,分离脾细胞,8.3% NH4Cl/0.17mol/LTris (pH 7.4)37℃作用10min去除红细胞,过玻璃毛柱,收集T淋巴细胞;用100:1含10% 胎牛血清、5×10-5mol/L二硫苏糖醇的DMEM完全培养液,以5×105/well浓度接种在96孔细胞培养板上,每例作3个重复孔。
1.3.3 IL-2、IFNr释放实验 小鼠脾T淋巴细胞,用10μg/ml rHBs体外刺激3天后,用U-CyTech公司的ELISA检测试剂盒测定培养上清的IL-2及FNr浓度。
1.3.4 51Cr释放CTL反应 靶细胞,P815细胞用特异性多肽处理,用100ul Na251CrO4在二氧化碳培养箱37℃标记1h。效应细胞,用含10% FCS的DMEM培养液悬浮小鼠脾细胞,加巯基乙醇至5×10-5M、小鼠IL-2至5u/ml,二氧化碳培养箱内培养5天后,培养液冲洗2次,按100:1、50:1与104标记的靶细胞在96孔细胞培养板上反应4h,每个实验对象检测3次;离心后,取100ul上清用r-记数计检测放射性,用以下公式计算特异性释放率,CTL特异性释放率=(实验组释放的量-自然释放的量)/(最大释放的量-自然释放的量)。