Mesman Annelies W, Westerhuis Brenda M, Ten Hulscher Hinke I, Jacobi Ronald H, de Bruin Erwin, van Beek Josine, Buisman Annemarie M, Koopmans Marion P, van Binnendijk Robert S
Centre for Infectious Disease Control (Cib), National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands.
J Gen Virol. 2016 Sep;97(9):2157-2165. doi: 10.1099/jgv.0.000552. Epub 2016 Jul 13.
Pre-existing immunity played a significant role in protection during the latest influenza A virus H1N1 pandemic, especially in older age groups. Structural similarities were found between A(H1N1)2009 and older H1N1 virus strains to which humans had already been exposed. Broadly cross-reactive antibodies capable of neutralizing the A(H1N1)2009 virus have been implicated in this immune protection in adults. We investigated the serological profile of a group of young children aged 9 years (n=55), from whom paired blood samples were available, just prior to the pandemic wave (March 2009) and shortly thereafter (March 2010). On the basis of A(H1N1)2009 seroconversion, 27 of the 55 children (49 %) were confirmed to be infected between these two time points. Within the non-infected group of 28 children (51 %), high levels of seasonal antibodies to H1 and H3 HA1 antigens were detected prior to pandemic exposure, reflecting past infection with H1N1 and H3N2, both of which had circulated in The Netherlands prior to the pandemic. In some children, this reactivity coincided with specific antibody reactivity against A(H1N1)2009. While these antibodies were not able to neutralize the A(H1N1)2009 virus, they were able to mediate antibody-dependent cellular cytotoxicity (ADCC) in vitro upon interaction with the A(H1N1)2009 virus. This finding suggests that cross-reactive antibodies could contribute to immune protection in children via ADCC.
既往免疫力在最近一次甲型H1N1流感大流行期间的保护作用中发挥了重要作用，尤其是在老年人群体中。2009年甲型H1N1流感病毒与人类之前接触过的较老的H1N1病毒株之间存在结构相似性。能够中和2009年甲型H1N1流感病毒的广泛交叉反应性抗体与成年人的这种免疫保护有关。我们调查了一组9岁幼儿（n = 55）的血清学特征，在大流行浪潮之前（2009年3月）和之后不久（2010年3月）可获得成对的血样。根据2009年甲型H1N1流感病毒血清转化情况，55名儿童中有27名（49%）在这两个时间点之间被确诊感染。在未感染的28名儿童组（51%）中，在大流行暴露之前检测到高水平的针对H1和H3 HA1抗原的季节性抗体，反映了过去感染过H1N1和H3N2，这两种病毒在大流行之前都曾在荷兰传播。在一些儿童中，这种反应性与针对2009年甲型H1N1流感病毒的特异性抗体反应性一致。虽然这些抗体不能中和2起甲型H1N1流感病毒，但它们在与2009年甲型H1N1流感病毒相互作用时能够在体外介导抗体依赖性细胞毒性（ADCC）。这一发现表明，交叉反应性抗体可能通过ADCC在儿童的免疫保护中发挥作用。
