Department of Respiratory and Critical Care Medicine, the Sixth Medical Center of PLA General Hospital, Beijing, China.
Hum Vaccin Immunother. 2022 Nov 30;18(6):2121565. doi: 10.1080/21645515.2022.2121565. Epub 2022 Sep 16.
Hand, foot and mouth disease was mainly caused by EV-A71 virus. The main antigen structure of VP1 region of EV-A71 was easily varied. Here, we investigated the seroprevalence of EV-A71 based on a large group of healthy individuals in Beijing, China, in order to study the effectiveness of EV-A71 vaccine in a real-world setting. BrCr and the clinical strain isolated from the Chinese mainland in 2008 ("vaccine strain:"CMU4232/BJ/CHN/2008), EV-A71 C4 epidemic strains isolated in 2010, 2013, and 2016, were tested for neutralizing antibodies (NtAb) in every year. Phylogenetic tree analysis of the EV-A71 strains above, as well as amino acid composition homologous sequence analysis were applied. The "vaccine strain" has 83.0% homology with FY23, H07 and FY7VP5. It belongs to the same branch of C4a as 10 C4, 13 C4 and 16 C4, and differs from the amino acid sites 283 and 293 of 16 C4. Compared with "vaccine strains," there was a significant difference between the 50-59 years old age group when the NtAb titer of 16 C4 strain was 1:512-1:1024. Our results suggest that changes in the functional epitopes of NtAb caused by amino acid 283 and 293 loci in EV-A71 strains may affect the production of neutralizing antibodies.
手足口病主要由肠道病毒 A71 型（EV-A71）引起。EV-A71 病毒 VP1 区主要抗原结构容易发生变异。本研究通过对我国北京地区的较大样本健康人群进行血清学调查，旨在了解肠道病毒 A71 型（EV-A71）在真实环境中的流行情况，评估 EV-A71 疫苗的免疫效果。应用 BrCr 细胞和本实验室分离的中国 2008 年临床株（“疫苗株”：CMU4232/BJ/CHN/2008）以及 2010 年、2013 年和 2016 年分离的 C4 流行株对各年度分离株进行中和抗体（NtAb）检测，同时对上述 EV-A71 毒株进行系统进化分析和氨基酸同源性比较。“疫苗株”与 FY23、H07 和 FY7VP5 同源性为 83.0%，与 10 株 C4、13 株 C4 和 16 株 C4 属于同一分支，与 16 株 C4 株的 283 位和 293 位氨基酸不同。与“疫苗株”比较，16 株 C4 株在 50-59 岁年龄组 NtAb 滴度 1:512-1:1024 时差异有统计学意义。提示 EV-A71 毒株 NtAb 中和表位氨基酸 283 位和 293 位的变异可能影响中和抗体的产生。
