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通过临床血清样本研究及实验动物验证,探讨肠道病毒71型(EV71)与脊髓灰质炎病毒(PV)之间的抗体交叉反应性。以酶联免疫吸附试验(ELISA)分别检测健康儿童血清中IgG型抗体与EV71及PV的反应性;用原核表达与亲和纯化等方法分别获得EV71和PV的衣壳蛋白VP1及非结构蛋白3C;将PV-VP1、EV71-VP1、EV71灭活疫苗及PV灭活疫苗(IPV)分别经皮下免疫BALB/c小鼠制得免疫血清,以蛋白免疫印迹实验分别研究PV-VP1或EV71-VP1小鼠阳性血清与EV71-VP1和PV-VP1的反应情况,进一步以竞争ELISA试验分别研究EV71-VP1对PV-VP1与其特异性免疫血清特异结合的影响。微量中和试验研究PV阳性抗血清对EV71的体外中和效应。结果:已接种PV疫苗但未曾感染EV71的健康儿童的IgG抗体与EV71有较高的反应性,且针对EV71及PV两种病毒的IgG抗体的相对含量成正相关;蛋白免疫印迹实验显示PV-VP1与EV71-VP1免疫的小鼠抗血清中存在交叉抗体,竞争ELISA试验进一步表明EV71-VP1蛋白能明显抑制PV-VP1与其特异性免疫血清抗体的结合,反之亦然。但中和实验揭示PV阳性血清在体外不能中和EV71病毒。PV之间存在大量交叉反应性抗体,但PV免疫后产生的与EV71交叉反应的抗体是非中和性质抗体。非中和抗体可能通过免疫调理效应在EV71病毒的致病的过程中发挥重要作用。
Antibody cross-reactivity between enterovirus 71 (EV71) and poliomyelitis virus (PV) was explored by clinical serum sample studies and laboratory animal validation. The reactivity of IgG antibodies with EV71 and PV in sera of healthy children were detected by enzyme linked immunosorbent assay (ELISA). The capsid protein VP1 and nonstructural protein 3C of EV71 and PV were obtained by prokaryotic expression and affinity purification, respectively The immune serums of BALB / c mice were immunized subcutaneously with PV-VP1, EV71-VP1, EV71 inactivated vaccine and PV inactivated vaccine (IPV) respectively. The expression of PV-VP1 or EV71-VP1 VP71 and PV-VP1 were detected by ELISA. The effect of EV71-VP1 on the specific binding of PV-VP1 to its specific immune serum was further studied by competitive ELISA. In Vitro Neutralization Effect of PV Positive Antiserum on EV71 in a Minimal Neutralization Test. Results: The IgG antibodies of healthy children who had been inoculated with PV vaccine but did not infect EV71 were highly reactive with EV71, and positively correlated with the relative content of IgG antibodies against both EV71 and PV viruses. Western blotting showed that PV-VP1 Cross-antibody was present in the antiserum of mice immunized with EV71-VP1, and the competitive ELISA assay further demonstrated that EV71-VP1 protein significantly inhibited the binding of PV-VP1 to its specific immune serum antibody and vice versa. Neutralization experiments revealed that PV-positive sera did not neutralize EV71 virus in vitro. A large number of cross-reactive antibodies exist between PVs, but antibodies that cross-react with EV71 after PV immunization are non-neutralizing antibodies. Non-neutralizing antibodies may play an important role in the pathogenesis of EV71 virus, possibly through immunomodulatory effects.