title: Salivary IgA antibody responses to Streptococcus mitis and Streptococcus mutans in preterm and fullterm newborn children.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: University of Uberaba, Minas Gerais, Brazil. ruchele_nogueira@yahoo.com.br
authors.forename: Ruchele Dias
authors.initials: RD
authors.lastname: Nogueira
authors.forename: Maria Lucia Talarico
authors.initials: ML
authors.lastname: Sesso
authors.forename: Mariana Castro Loureiro
authors.initials: MC
authors.lastname: Borges
authors.forename: Renata O
authors.initials: RO
authors.lastname: Mattos-Graner
authors.forename: Daniel James
authors.initials: DJ
authors.lastname: Smith
authors.forename: Virginia Paes Leme
authors.initials: VP
authors.lastname: Ferriani
mesh_terms: D000917:Antibody Formation / Q000276:immunology*; D015153:Blotting, Western; D016009:Chi-Square Distribution; D013293:Enterococcus faecalis / Q000276:immunology / Q000302:isolation & purification; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology; D007231:Infant, Newborn; D007234:Infant, Premature / Q000276:immunology; D008297:Male; D008895:Milk, Human / Q000276:immunology; D009055:Mouth / Q000737:chemistry / Q000276:immunology* / Q000382:microbiology; D012463:Saliva / Q000737:chemistry / Q000276:immunology*; D018709:Statistics, Nonparametric; D034361:Streptococcus mitis / Q000276:immunology* / Q000302:isolation & purification; D013295:Streptococcus mutans / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D007071:Immunoglobulin A, Secretory; D007075:Immunoglobulin M