肠道病毒71型疫苗的中和抗体应答研究

目的:比较我国不同企业研发的肠道病毒 71 型(EV71)疫苗原液和成品疫苗的小鼠中和抗体应答,为疫苗临床试验提供依据。方法: 应用来源于 3 家疫苗研发企业的 EV71 疫苗原液(Y1、Y2、Y3),以及相应原液制备的 3 批成品疫苗(临床申报剂量:M1、M2、M3;相同抗原含量:M1-1、M2-1、M3-1),分别采取 2 针程序免疫小鼠,检测免疫 1 针和 2 针后血清中和抗体效价。结果: 分别来自不同生产企业的 3 个 EV71 疫苗原液免疫原性相近,免疫剂量均为 430 U/0.5 mL/只 时, 1 针后中和抗体阳性率为 83.3%~90.0%,2 针均为100%,中和抗体效价分别为 1:34.9~1:45.9 和1:139.4~1:285.7;与 Al(OH)₃吸附后,3 批成品疫苗的免疫原性均出现明显增强,162 U/0.5 mL/只 的剂量即均可得到与 430 U/0.5 mL/只 原液相近的抗体阳转率和效价, 2 针免疫后 M3-1 抗体效价显著高于 M1-1和 M2-1(1:357.3、1:111.3和1:97.9,P分别为 0.004 和 0.001)。当 3 批疫苗均采用临床申报剂量免疫时(162,493,506 U/0.5 mL/只),1 针免疫后中和抗体阳性率(80%~100%)和抗体效价(1:46.8~1:115.4)均无显著性差异(P值均>0.05),2 针后中和抗体阳性率均为 100%,M3 批抗体效价显著高于M1批(1:958.2、1:316.8,P值为 0.017)。结论: 3 家企业 EV71 原液的免疫原性接近,成品疫苗 2 针免疫后均可诱导高效价中和抗体产生,但不同企业的中和抗体升高水平呈现差别,提示临床试验中需重点比较含佐剂疫苗加免后的免疫原性。

Objective: To compare the neutralizing antibody (NTAb) responses of vaccine stock solutions and final vaccines of Enterovirus 71(EV71) in mice,and provide bases for the further clinical trails of EV71 vaccines. Methods: The immunization schedule consisted of two inoculations in mice separately.ICR mice were immunized with three kinds of aqueous bulks of EV71(Y1,Y2,Y3)from three enterprises and three kinds of EV71 finial lot vaccines (Clinical declaring dose:M1,M2,M3;Equal antigenic concentration:M1-1,M2-1,M3-1).And the NTAb titers of sera were tested after the first inoculation and the second inoculation,respectively. Results: Three kinds of aqueous bulks from different strains and preparations showed the close immunogenicity.When immunizing dose was 430 U/0.5 mL/each mouse,the positive rate of NTAb was 83.3%-90.0% after the 1st inoculation and 100% after the 2^ndinoculation;with Geometric Mean Titers (GMTs) of NTAb was 1:34.9-1:45.9 and 1:139.4-1:285.7,respectively.Moreover,the immunogenicity of three bulk finished vaccines after adsorbed with Al(OH)₃ all significantly increased,in result the positive rate of NTAb of finished vaccines (162 U/0.5 mL/each mouse) was close to that of vaccine stock solutions (430 U/0.5 mL/each mouse).After two immunizations,GMTs of M3-1 was significantly higher than that of M1-1 and M2-1(1:357.3,1:111.3,1:97.9;P=0.004 and 0.001).When clinical declaring doses (162,493,506 U/0.5 mL/each mouse) were employed for three vaccine products,there existed no significant difference between the positive rates of NTAb(80%-100%)and between antibody GMTs(1:46.8-1:115.4)after the 1st inoculation(P>0.05),and the positive rates of NTAb were all 100% after the 2nd inoculation.In addition,antibody GMTs of M3 was significantly higher than that of M1(1:958.2,1:316.8;P=0.017).Conclusion: The immunogenicity of EV71 vaccine aqueous bulk solutions from three different enterprises are close to each other and high-titers NTAb is induced after two inoculations.However,significant difference in increased levels of NTAb among finial lot vaccines from different enterprises is observed,which suggests that the comparison of immunogenicity should be focused on vaccines containing aluminium adjuvant in clinical trails after boost dose.