Simell Birgit, Melin Merit, Lahdenkari Mika, Briles David E, Hollingshead Susan K, Kilpi Terhi M, Kayhty Helena
Department of Vaccines, National Public Health Institute, Mannerheimintie 166, Helsinki, Finland.
J Infect Dis. 2007 Nov 15;196(10):1528-36. doi: 10.1086/522607. Epub 2007 Oct 31.
Pneumococcal surface protein A (PspA) is a highly variable yet cross-reactive protein that exists as 2 major families. We assessed the development of human serum and salivary antibodies against the PspA families 1 (PspA1) and 2 (PspA2) in early childhood and their role in the prevention of pneumococcal acute otitis media (AOM).
Serum levels of IgG and salivary levels of IgA antibodies to PspA1 and PspA2 were measured by use of enzyme immunoassay from the samples from the Finnish Otitis Media Cohort Study obtained at the ages of 12 months (287 and 160 samples, respectively) and 18 months (258 and 131 samples, respectively). The Cox proportional hazard model was used to evaluate the relative risk (RR) of pneumococcal AOM during the 6 months after sampling relative to concentration of serum or presence of salivary anti-PspA in the samples.
Anti-PspA1 and anti-PspA2 concentrations at 12 and 18 months were related to prior culture-confirmed pneumococcal exposure. The concentrations of serum anti-PspA were not significantly associated with the risk of pneumococcal AOM. At 18 months, the presence of salivary anti-PspA was significantly associated with a lower risk of pneumococcal AOM during the 6 months after sampling (RR, 0.27 [95% confidence interval, 0.11-0.69]).
The lowered risk of pneumococcal AOM associated with the presence of salivary anti-PspA at 18 months suggests that mucosal anti-PspA antibodies have a role in the prevention of pneumococcal AOM.
肺炎球菌表面蛋白A（PspA）是一种高度可变但具有交叉反应性的蛋白，以两个主要家族形式存在。我们评估了幼儿期针对PspA家族1（PspA1）和家族2（PspA2）的人血清和唾液抗体的产生情况及其在预防肺炎球菌性急性中耳炎（AOM）中的作用。
采用酶免疫测定法，检测芬兰中耳炎队列研究中12个月龄（分别为287份和160份样本）和18个月龄（分别为258份和131份样本）时采集的样本中针对PspA1和PspA2的IgG血清水平和IgA唾液水平。采用Cox比例风险模型评估采样后6个月内肺炎球菌性AOM相对于血清浓度或样本中唾液抗PspA存在情况的相对风险（RR）。
12个月和18个月时抗PspA1和抗PspA2浓度与先前经培养确诊的肺炎球菌暴露有关。血清抗PspA浓度与肺炎球菌性AOM风险无显著相关性。在18个月时，唾液中抗PspA的存在与采样后6个月内肺炎球菌性AOM风险较低显著相关（RR，0.27[95%置信区间，0.11 - 0.69]）。
18个月时唾液抗PspA的存在与肺炎球菌性AOM风险降低相关，提示黏膜抗PspA抗体在预防肺炎球菌性AOM中起作用。
