mutans in saliva of predentate infants who did not harbour S. mutans, 15 here, the presence of specific antibody at birth is unlikely to have been induced within 10 h, since it takes at least a week for the uptake, processing of

antigen, B cell selection and migration to local sites, differentiation into plasma cells leading to antibody secretion and endosomal transfer into the gland lumen. Thus, some hypotheses can be raised to address this early response of SIgA to S. mutans and S. mitis antigens. Firstly, the presence of residual of IgA from maternal milk in the oral cavity of children cannot be excluded, even though the samples have been collected at least 3 h after breastfeeding. For this reason, we compared immunoblotting of infant salivary samples with their respective maternal milk samples ( Fig. 2B). The majority of antigens that were more frequently reactive in www.selleckchem.com/products/sd-208.html the infant salivary samples were not recognized by maternal milk ( Fig. 2B). Additionally, immunoblots from children who did not receive maternal milk ( Fig. 1A, pair 10) presented with IgA antibody reactivity with S. mutans and S. mitis antigens. The persistence of secretory antibodies in the oral cavity (e.g., following breast feeding) strongly depend on their adhesion to salivary pellicle

on tooth surfaces. 26 Since newborns are edentulous, this condition for persistence of maternal IgA is absent. An alternative SGI-1776 cell line hypothesis could be associated with the plurispecific protection at mucosal surfaces, proposed by Quan and coworkers,27 isometheptene who found that SIgA antibodies from human saliva reacted with actin, myosin and tubulin but also with antigens from Streptococcus pyogenes. Also, those antibodies could result from stimulation without antigenic exposure, as the result of anti-idiotype induction 28 or intra-uterine stimulation. Thus, several bacteria have been isolated from umbilical cord blood, amniotic fluid and foetal membranes without clinical or histological evidence of infection or inflammation in pairs of mothers

and children. 29 In summary, the results show that detectable levels of salivary IgA antibodies reactive to oral bacterial species can be detected within the first hours after birth. Furthermore, the salivary IgA concentrations and IgA antibody specificities appear to influenced by the gestational age, which might reflect the level of immunological maturity of the mucosal immune system. These findings support further study about the investigation of antibody and microbial sources from mother in order to clarify the role and development of mucosal immune response in neonates. Conflict of interest: The authors declare no conflict of interest. Funding: This study was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), proc. 07/57346-5, and proc. 07/50807-7 and Conselho Nacional de Pesquisa (CNPq), proc. 472928/2007-4.