冻干甲型肝炎减毒活疫苗诱导的人体特异性免疫应答

目的观察人体接种冻干甲型肝炎减毒活疫苗(H2株)后产生的特异性免疫应答。方法选择16名血清甲型肝炎抗体阴性的健康志愿者,接种1针冻干甲型肝炎减毒活疫苗,接种前和接种后2、4、8、12、156周(3年)采血,采用ELISA检测血清抗HAVIgG抗体;采用流式细胞术检测全血各淋巴细胞亚群CD3+、CD4+、CD8+的百分率及表达细胞因子IFN-γ和IL-4的阳性细胞百分率;采用ELISPOT法检测外周血淋巴细胞分泌IFN-γ的斑点形成细胞(SFC)。结果接种疫苗后2周,表达IL-4的阳性细胞百分率与接种前相比显著升高;接种后4周,CD4+淋巴细胞亚群百分率与接种前相比显著升高;接种后8周,抗体100%阳转;接种后3年,抗体和分泌IFN-γ的SFC有一项以上阳性者占85.7%(12/14)。结论接种冻干甲型肝炎减毒活疫苗,能诱导机体产生良好的体液免疫和细胞免疫应答。

Specific Immune Responses Induced by Freeze-dried Live Attenuated Hepatitis A Vaccine in Humans

Objective To observe the specific immune responses induced by freeze-dried live attenuated hepatitis A(HA) vaccine(H2 strain)in humans.Methods Sixteen healthy volunteers negative for serum HA antibody were inoculated with one dose of freeze-dried live attenuated HA vaccine.The blood samples were collected before and 2,4,8,12 and 156 weeks(3 years)after in-oculation and determined for anti-HAV IgG by ELISA,for the percentages of CD3+,CD4+ and CD8+ lymphocyte subsets as well as positive cells expressing IFN-γ and IL-4 by flow cytometry,and for spot forming cells(SFCs)secreting IFN-γ by ELISPOT method.Results The percentage of positive cells expressing IL-4 2 weeks after inoculation was significantly higher than that before inoculation.The percentage of CD4+ lymphocyte subsets 4 weeks after inoculation was significantly higher than that before inoculation.Eight weeks after inoculation,the anti-HAV IgG positive rate reached 100%.Three years after inoculation,85.7%(12 / 14)of volunteers were positive for anti-HAV IgG and / or SFCs.Conclusion Freeze-dried live attenuated HA vaccine has induced good humoral and cellular immune responses in humans.