Rubin Steven, Mauldin Jeremy, Chumakov Konstantin, Vanderzanden Jackie, Iskow Rebecca, Carbone Kathryn
Center for Biologics Evaluation and Research, FDA, Bethesda, MD 20892, USA.
Vaccine. 2006 Mar 24;24(14):2662-8. doi: 10.1016/j.vaccine.2005.10.050. Epub 2005 Nov 8.
The recent resurgence of mumps epidemics in many countries with ongoing vaccination programs along with evidence of antigenic diversity among mumps virus strains have recently challenged the assumption that mumps virus is serologically monotypic. To address this controversy, we sought to identify two mumps virus strains that would best represent different serotypes, should multiple serotypes exist, and assess the ability of human sera to neutralize both strains. The virus strains, Enders and Lo1, were selected based upon a phylogenetic analysis of the major target of neutralizing antibody, the viral hemagglutinin-neuraminidase (HN) protein, along with data reported by others indicating that (1) these viruses are antigenically distinct and (2) genotypically similar strains have been implicated in cases of reinfection. Our results show that of sera capable of neutralizing one of the virus strains, 90% could neutralize the other, although significant differences in neutralization titers were noted. Though the latter confirms the existence of inter-strain antigenic variability, the fact that few sera were unable to neutralize both virus strains argues against the presence of multiple serotypes. Of those sera incapable of co-neutralization, all but one had low neutralization titers (1:8), suggesting that individuals possessing low levels of neutralizing antibody may be at risk for breakthrough infections, thereby providing an explanation for cases of infection in previously infected or vaccinated individuals.
在许多实施疫苗接种计划的国家，近期腮腺炎疫情再度爆发，同时有证据表明腮腺炎病毒株之间存在抗原多样性，这对腮腺炎病毒血清学上为单一型的假设提出了挑战。为解决这一争议，我们试图确定两种腮腺炎病毒株，如果存在多种血清型，它们能最好地代表不同血清型，并评估人血清中和这两种病毒株的能力。根据对中和抗体的主要靶标——病毒血凝素神经氨酸酶（HN）蛋白的系统发育分析，以及其他人报告的数据，选择了Enders和Lo1这两种病毒株，这些数据表明：（1）这些病毒在抗原性上不同；（2）基因型相似的病毒株与再次感染病例有关。我们的结果显示，能够中和其中一种病毒株的血清中，90%能够中和另一种病毒株，尽管中和效价存在显著差异。尽管后者证实了病毒株间存在抗原变异性，但很少有血清不能中和这两种病毒株这一事实表明不存在多种血清型。在那些不能共同中和的血清中，除一份血清外，其他所有血清的中和效价都很低（1:8），这表明中和抗体水平低的个体可能有突破性感染的风险，从而解释了既往感染或接种过疫苗的个体发生感染的病例。
