灭活与减毒两种甲肝疫苗免疫后诱导细胞免疫应答初探

目的 对国内普遍应用的减毒和灭活甲肝疫苗诱导的细胞免疫水平(产生时间、应答水平)进行检测和比较.方法 筛选健康志愿者18人,随机分组后分别接种甲肝减毒活疫苗和甲肝灭活疫苗.按实验程序以周次为时间点采血,用化学发光法对特异性甲肝抗体(HAY-IgG)进行检测;同时收集外周血单个核细胞(PBMC),用特异性甲肝抗原刺激后,以酶联免疫斑点试验(ELISPOT)法检测效应T细胞分泌TH1型细胞因子IFN-γ的情况;用胞内细胞因子染色法测定CD+ T和CD8+T淋巴细胞中分泌IFN-γ的阳性细胞百分比,Lumlnex法检测细胞培养上清中IFN-γ、IL-2、IL-10、IL-4等多种细胞因子水平.结果 两种疫苗均可诱导产生特异性抗HAV抗体,且观测期间抗体水平差异无统计学意义.两种疫苗接种初期即可诱导产生病毒特异性T细胞免疫应答反应,同时伴随高水平的效应细胞因子IFN-γ产生.在免疫接种后1-3周,灭活疫苗诱导的细胞免疫应答水平高于减毒疫苗;而在4-6周,减毒疫苗诱导的细胞免疫应答水平明显增高,超过灭活疫苗.灭活疫苗所诱导的细胞免疫应答在加强免疫后明显增强.结论 两种疫苗接种初期均可诱导体液和细胞免疫应答;灭活疫苗加强免疫后可激发记忆性免疫应答.

Primary research on cellular immune response induced by live attenuated and inactiveated hepatitis A vaccines

Objective To evaluate and compare the cellular immune response induced by live at-tenuated and inactivated hepatitis A vaccines. Methods A total of 18 healthy volunteers were enrolled in this study. They were divided randomly into 2 groups and injected by inactivated hepatitis A vaccine and at-tenuated hepatitis A vaccine, respectively. All volunteers' heparinized venous blood was separately collected for testing anti-HAV antibody and the responses of PBMC. The level of IFN-γsecreted by effect T cell was tested by ELISPOT. The percentage of lymphocytes secreting IFN-γ from CD+ and CD8+ T cell was tested by intracellular cytokine staining (ICS) technique. The concentrations of IFN-γ, IL-2, IL-10 and IL-4 in the culture supernatants(grown in the presence or absence of HAV) of the in vitro HAV-primed PBMC were determined by Luminex. Results These two types of vaccines can elicit specific anti-HAY antibodies and no statistical significance between them were observed. At the early stage after inoculation, T cell-mediated immune responses with the secretion of IFN-γ were detected in vaccines inoculated with either type of vac-cines. There was a tendency that the cellular immune responses level induced by inactivated hepatitis A vac-cine was higher than that by live attenuated hepatitis A vaccine during 1 to 3 weeks post-injection. The booster inoculation could significantly increase the level of cellular immune responses induced by the inacti-vated vaccine. Conclusion Both live attenuated and inactivated HAV vaccines can elicit an earlier specific humoral and cellular immune responses, and booster inoculation of inactivated HAV vaccine can rapidly and intensively evoke memory immune responses.