Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford OX3 7LE, United Kingdom.
J Immunol. 2012 Sep 1;189(5):2673-81. doi: 10.4049/jimmunol.1200451. Epub 2012 Aug 1.
The maintenance of adequate serum Ab levels following immunization has been identified as the most important mechanism for individual long-term protection against rapidly invading encapsulated bacteria. The mechanisms for maintaining adequate serum Ab levels and the relationship between Ag-specific memory B cells and Ab at steady state are poorly understood. We measured the frequency of circulating serogroup C meningococcal (MenC)-specific memory B cells in 250 healthy 6- to 12-y-old children 6 y following MenC conjugate vaccine priming, before a booster of a combined Haemophilus influenzae type b-MenC conjugate vaccine and then 1 wk, 1 mo, and 1 y after the booster. We investigated the relationship between circulating MenC-specific memory B cell frequencies and Ab at baseline and following the booster vaccine. We found very low frequencies of circulating MenC-specific memory B cells at steady state in primary school-aged children and little association with MenC IgG Ab levels. Following vaccination, there were robust memory B cell booster responses that, unlike Ab levels, were not dependent on age at priming with MenC. Measurement of B cell memory in peripheral blood does not predict steady state Ab levels nor the capacity to respond to a booster dose of MenC Ag.
接种疫苗后维持足够的血清 Ab 水平已被确定为个体长期抵御快速侵袭性囊膜细菌的最重要机制。维持足够的血清 Ab 水平的机制以及 Ag 特异性记忆 B 细胞与稳定状态下 Ab 之间的关系尚未得到很好的理解。我们在接种 MenC 结合疫苗 6 年后，即接种 MenC 结合疫苗 1 周、1 个月和 1 年后，测量了 250 名 6 至 12 岁健康儿童接种 MenC 结合疫苗后循环血清群 C 脑膜炎奈瑟菌（MenC）特异性记忆 B 细胞的频率，然后在加强免疫接种联合型流感嗜血杆菌 b-MenC 结合疫苗之前。我们研究了循环 MenC 特异性记忆 B 细胞频率与基线和加强疫苗接种后 Ab 之间的关系。我们发现，在小学年龄段的儿童中，循环 MenC 特异性记忆 B 细胞的频率非常低，与 MenC IgG Ab 水平几乎没有关联。接种疫苗后，出现了强烈的记忆 B 细胞增强反应，与 Ab 水平不同，这种反应不受 MenC 疫苗初次接种时年龄的影响。外周血 B 细胞记忆的测量既不能预测 Ab 水平的稳定状态，也不能预测对 MenC Ag 加强剂量的反应能力。
