University of Uberaba, Minas Gerais, Brazil.
Arch Oral Biol. 2012 Jun;57(6):647-53. doi: 10.1016/j.archoralbio.2011.11.011. Epub 2011 Dec 12.
The intensities and specificities of salivary IgA antibody responses to antigens of Streptococcus mutans, the main pathogen of dental caries, may influence colonization by these organisms during the first 1.5 year of life. Thus, the ontogeny of salivary IgA responses to oral colonizers continues to warrant investigation, especially with regard to the influence of birth conditions, e.g. prematurity, on the ability of children to efficiently respond to oral microorganisms. In this study, we characterised the salivary antibody responses to two bacterial species which are prototypes of pioneer and pathogenic microorganisms of the oral cavity (Streptococcus mitis and Streptococcus mutans, respectively) in fullterm (FT) and preterm (PT) newborn children.
Salivas from 123 infants (70 FT and 53 PT) were collected during the first 10h after birth and levels of IgA and IgM antibodies and the presence of S. mutans and S. mitis were analysed respectively by ELISA and by chequerboard DNA-DNA hybridization. Two subgroups of 24 FT and 24 PT children were compared with respect to patterns of antibody specificities against S. mutans and S. mitis antigens, using Western blot assays. Cross-adsorption of 10 infant's saliva was tested to S. mitis, S. mutans and Enterococcus faecalis antigens.
Salivary levels of IgA at birth were 2.5-fold higher in FT than in PT children (Mann-Whitney; P<0.05). Salivary IgA antibodies reactive with several antigens of S. mitis and S. mutans were detected at birth in children with undetectable levels of those bacteria. Adsorption of infant saliva with cells of S. mutans produced a reduction of antibodies recognizing S. mitis antigens in half of the neonates. The diversity and intensity of IgA responses were lower in PT compared to FT children, although those differences were not significant.
These data provide evidence that children have salivary IgA antibodies shortly after birth, which might influence the establishment of the oral microbiota, and that the levels of salivary antibody might be related to prematurity.
唾液免疫球蛋白 A（IgA）对变形链球菌（龋齿的主要病原体）抗原的应答强度和特异性可能会影响这些微生物在生命最初 1.5 年内的定植。因此，唾液 IgA 对口腔定植菌的应答发育仍然需要研究，特别是要关注出生条件（如早产）对儿童有效应对口腔微生物的能力的影响。在这项研究中，我们对口腔先驱和病原微生物（分别为表兄链球菌和变形链球菌）的两种细菌的唾液抗体应答进行了特征描述，这些细菌的研究对象是足月（FT）和早产（PT）新生儿。
收集了 123 名婴儿（70 名 FT 和 53 名 PT）出生后 10 小时内的唾液，并分别通过 ELISA 和斑点杂交 DNA-DNA 杂交分析 IgA 和 IgM 抗体水平以及变形链球菌和表兄链球菌的存在情况。使用 Western blot 检测，对 24 名 FT 和 24 名 PT 儿童的针对变形链球菌和表兄链球菌抗原的抗体特异性模式进行了比较。对 10 名婴儿唾液进行交叉吸附实验，以测试其对表兄链球菌、变形链球菌和粪肠球菌抗原的反应。
FT 婴儿出生时唾液 IgA 水平比 PT 婴儿高 2.5 倍（Mann-Whitney；P<0.05）。在检测不到这些细菌的儿童中，出生时就检测到了针对表兄链球菌和变形链球菌多种抗原的唾液 IgA 抗体。用变形链球菌细胞吸附婴儿唾液后，有一半的新生儿识别表兄链球菌抗原的抗体减少了一半。PT 婴儿的 IgA 应答的多样性和强度均低于 FT 婴儿，但这些差异无统计学意义。
这些数据表明，儿童在出生后不久就有唾液 IgA 抗体，这可能会影响口腔微生物群的建立，并且唾液抗体的水平可能与早产有关。
