Gérentes L, Kessler N, Aymard M
National Influenza Reference Center, Laboratoire de Virologie - C.H.U. de Lyon, France.
Dev Biol Stand. 1999;98:189-96; discussion 197.
To achieve better standardization of influenza vaccines, an ELISA immunocapture assay was developed for N2 neuraminidase quantification. This sensitive and highly specific assay was successfully applied to vaccine preparations produced in embryonated hens' eggs from 1992 to 1997 and to antigenically related viral suspensions produced in MDCK cells. A study of the neuraminidase activity of prototype A/H3N2 strains stored at 4 degrees C showed the gradual development of enzymatic instability from 1994 onwards, accompanied by antigenic modifications of the antigen. As the phenomenon was also more pronounced with the recombinant, the question arose of the standard of immunity provided when such viruses are used for vaccination. The antibodies inhibiting neuraminidase activity in vaccinated subjects were monitored in parallel using both complete virus and purified N2 NA. The study revealed the existence of an interference phenomenon which resulted in the titre of the N1 antibodies being overestimated. The interference was due to anti-HA antibodies impeding access to the substrate at the enzymatic site by steric hindrance.
为实现流感疫苗更好的标准化，开发了一种用于N2神经氨酸酶定量的ELISA免疫捕获测定法。这种灵敏且高度特异的测定法已成功应用于1992年至1997年在鸡胚中生产的疫苗制剂以及在MDCK细胞中生产的抗原相关病毒悬液。对保存在4摄氏度的A/H3N2原型毒株的神经氨酸酶活性研究表明，从1994年起酶稳定性逐渐发展，同时伴随着抗原的抗原性改变。由于这种现象在重组体中也更明显，因此出现了使用此类病毒进行疫苗接种时所提供免疫标准的问题。同时使用完整病毒和纯化的N2 NA监测接种者中抑制神经氨酸酶活性的抗体。该研究揭示了一种干扰现象，导致N1抗体的效价被高估。这种干扰是由于抗HA抗体通过空间位阻阻碍酶位点对底物的接触。
