Kenya Medical Research Institute - Wellcome Trust Research Programme, Kilifi, Kenya.
Respiratory & Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa.
Sci Rep. 2018 Oct 18;8(1):15376. doi: 10.1038/s41598-018-33735-x.
Children in developing countries are frequently exposed to the pneumococcus, but few develop invasive pneumococcal disease (IPD). We test the hypothesis that natural variation exists in the rapidity of IgG responses following exposure to pneumococcal polysaccharides, and that these differences are sufficiently great to affect susceptibility to and outcome of IPD. We recruited children aged 24-36 months, who had recovered from IPD, and age-matched healthy controls and vaccinated them with 1 dose of the 23-valent PPV to mimic natural exposure. We collected serum samples after vaccination and analysed the dynamics of anti-polysaccharide antibody responses to several capsular antigens. Mean IgG response times to different serotypes were 6.4-7.3 days, with standard deviations of 0.9-1.85 days, suggesting a natural range in response times of up to 7 days. Serotype 1 elicited the largest fold-rise, serotype 23F the smallest. The proportion of responses achieved by day 7 was similar in children with a history of IPD and healthy children. There was considerable natural variation in the rapidity of anti-capsular IgG responses extending over 4-7 days. There was no evidence to suggest that children who have experienced IPD respond more slowly to heterologous pneumococcal capsular antigens than do healthy children.
发展中国家的儿童经常接触肺炎球菌，但很少发生侵袭性肺炎球菌病（IPD）。我们验证了这样一个假设，即在接触肺炎球菌多糖后，IgG 反应的速度存在自然变异，并且这些差异足够大，会影响 IPD 的易感性和结果。我们招募了年龄在 24-36 个月、已从 IPD 中康复的儿童和年龄匹配的健康对照者，并给他们接种一剂 23 价肺炎球菌多糖疫苗（PPV），以模拟自然接触。我们在接种后采集血清样本，并分析针对几种荚膜抗原的抗多糖抗体反应的动力学。对不同血清型的 IgG 反应时间平均为 6.4-7.3 天，标准差为 0.9-1.85 天，表明反应时间的自然范围可达 7 天。血清型 1 引起的倍数上升最大，血清型 23F 引起的倍数上升最小。有 IPD 病史的儿童和健康儿童在第 7 天达到反应的比例相似。抗荚膜 IgG 反应的速度存在相当大的自然变异，可延长至 4-7 天。没有证据表明经历过 IPD 的儿童对异源肺炎球菌荚膜抗原的反应速度比健康儿童慢。
