Recognition of Gram-positive Intestinal Bacteria by Hybridoma- and Colostrum-derived Secretory Immunoglobulin A Is Mediated by Carbohydrates

摘要: Humans live in symbiosis with 1014 commensal bacteria among which >99% resides their gastrointestinal tract. The molecular bases pertaining to the interaction between mucosal secretory IgA (SIgA) and residing intestine are not known. Previous studies have demonstrated that commensals naturally coated by SIgA gut lumen. Thus, understanding how natural interacts can provide new clues on its multiple functions at surfaces. Using fluorescently labeled, nonspecific or component (SC), we visualized confocal microscopy various bacteria, including Lactobacillus, Bifidobacteria, Escherichia coli, Bacteroides strains. These experiments revealed involves Fab- Fc-independent structural motifs, featuring SC as a crucial partner. Removal of glycans present free bound resulted drastic drop Gram-positive indicating essential role carbohydrates process. In contrast, poor binding control IgG was observed. Gram-negative preserved whatever form protein partner used, suggesting involvement different motifs. Purified from either mouse hybridoma cells human colostrum exhibited identical patterns recognition for emphasizing conserved plasticity species. sugar-mediated highlights currently underappreciated mediating highly diverse microbiota immune system.