柯萨奇病毒A组6型中和抗体检测用毒株病毒滴度标定及其专属性和适用性评价

Calibration of virus titer of coxsackievirus A6 strain for neutralizing antibody determination and evaluation of its specificity and applicability

目的对柯萨奇病毒A组6型(coxsackievirus A6,CA6)中和抗体检测用毒株进行病毒滴度标定,并评价该毒株的专属性和适用性。方法由3名实验员(A、B、C)在3 d内对CA6候选检测毒株分别进行3次独立的病毒滴度测定,标定该毒株的病毒滴度。采用CA6候选检测毒株测定CA6、肠道病毒71型(enterovirus 71,EV71)、柯萨奇病毒A组16型(coxsackievirus A16,CA16)、柯萨奇病毒A组10型(coxsackievirus A10,CA10)小鼠免疫血清的中和效价,同时检测12份CA6小鼠免疫血清和12份CA6自然感染人血清的中和效价。结果A、B、C实验员测定CA6候选检测毒株病毒滴度均值分别为(7.861±0.075)、(7.819±0.110)、(7.875±0.140)LgCCID/mL,检测结果差异无统计学意义(P>0.05),最终标定病毒滴度为7.852 LgCCID_(50)/mL。该毒株仅可与CA6小鼠免疫血清发生中和反应,与EV71、CA16、CA10免疫血清无交叉反应。每份小鼠免疫血清和自然感染人血清中和抗体效价的最大值与最小值比值(MAX/MIN)均<4,CV在1.65%~12.44%之间。结论CA6候选检测毒株具有良好的专属性和适用性,可用于CA6中和抗体的检测。

Objective To calibrate the virus titer of coxsackievirus A6(CA6)strain for determination of neutralizing antibody,and evaluate its specificity and applicability in the determination method.Methods The candidate CA6 strain was calibrated for virus titer for 3 times independently by three laboratory operators(A,B and C)within 3 d,by which the serum neutralizing antibody titers against CA6,enterovirus 71(EV71),coxsackievirus A16(CA16)and coxsackievirus A10(CA10)as well as those of 12 serum samples from immunized mice and 12 naturally infected human serum samples were determined.Results The mean titers of candidate CA6 strain measured by laboratory operators A,B and C were(7.861±0.075),(7.819±0.110)and(7.875±0.140)LgCCID/mL respectively,which showed no significant difference(P>0.05),and the finally calibrated virus titer was 7.852 LgCCID_(50)/mL.The strain showed only neutralizing reaction with mouse immune serum against CA6,while showed no cross reaction with those against EV71,CA16 and CA10.The ratios of maximum to minimum(MAX/MIN)of neutralizing antibody titer in each mouse immune serum and naturally infected human serum samples were less than 4,with CVs of 1.65%~12.44%.Conclusion The candidate CA6 strain showed good specificity and applicability,which might be used for the determination of neutralizing antibody against CA6.