Finn Adam, Zhang Qibo, Seymour Lynn, Fasching Claudine, Pettitt Emily, Janoff Edward N
Institute of Child Health, University of Bristol, Bristol, United Kingdom.
J Infect Dis. 2002 Nov 15;186(10):1422-9. doi: 10.1086/344356. Epub 2002 Oct 23.
Capsule-specific secretory IgA (s-IgA) in breast milk may enhance protection against pneumococcal disease in infants. After immunization of 3 lactating mothers with 23-valent polysaccharide vaccine, specific s-IgA, but not IgG, increased by >2-fold in milk of at least 1 subject for 6 of 7 serotypes. The s-IgA was predominantly IgA1, in secretory form, and highly specific with avidity distinct from serum IgA and IgG. Milk whey from 2 immunized women supported dose- and complement-dependent killing of Streptococcus pneumoniae serotypes 19F and 14 by human neutrophils, as did purified s-IgA to serotype 19F. These data reveal that capsule-specific human s-IgA in breast milk can initiate killing of S. pneumoniae, providing proof of concept that vaccine-induced human mucosal s-IgA can support functional bactericidal activity. Determining the biologic role for s-IgA in killing and inhibiting adherence of S. pneumoniae in vivo will contribute to the development of mucosal vaccines against S. pneumoniae.
母乳中针对荚膜的分泌型 IgA（s-IgA）可能增强婴儿抵御肺炎球菌疾病的能力。在用 23 价多糖疫苗免疫 3 名哺乳期母亲后，至少 1 名受试者的乳汁中，7 种血清型中的 6 种血清型的特异性 s-IgA 而非 IgG 增加了 2 倍以上。s-IgA 主要为分泌形式的 IgA1，具有高度特异性，其亲和力与血清 IgA 和 IgG 不同。2 名免疫女性的乳清支持人中性粒细胞对 19F 和 14 型肺炎链球菌进行剂量和补体依赖性杀伤，针对 19F 型的纯化 s-IgA 也有此作用。这些数据表明，母乳中针对荚膜的人 s-IgA 可启动对肺炎链球菌的杀伤，证明了疫苗诱导的人黏膜 s-IgA 可支持功能性杀菌活性这一概念。确定 s-IgA 在体内杀伤和抑制肺炎链球菌黏附中的生物学作用，将有助于开发针对肺炎链球菌的黏膜疫苗。
