title: Secretory immunoglobulin A heavy chain presents Galbeta1-3GalNAc binding structures for Actinomyces naeslundii genospecies 1.
abstract: Adherence of Actinomyces naeslundii ATCC 12104 to hydroxyapatite beads coated with protein fractions of parotid saliva, obtained by gel filtration on S-200 HR columns, showed GalNAcbeta1-3Galalpha-O-ethyl-inhibitable binding to high-molecular-weight proteins (Strömberg et al., 1992). The present study investigates the nature of these high-molecular-weight binding proteins and determines their specific ability to mediate adherence to representative strains of Actinomyces species. Strain ATCC 12104 bound specifically in a lactose-inhibitable manner to the heavy chain of secretory immunoglobulin A (S-IgA), contained within a high-molecular-weight parotid protein fraction separated on SDS-PAGE and transferred to a solid membrane support. Lactose-inhibitable binding to the heavy chain of S-IgA from human colostrum was also demonstrated. Peanut agglutinin bound to the heavy chain of parotid and colostrum S-IgAs contained on solid support membranes, confirming the presence of Galbeta1-3GalNAc residues on these molecules. Both salivary and colostrum S-IgA aggregated with strain ATCC 12104 in a GalNAcbeta1-3Galalpha-O-ethyl-inhibitable fashion. Further separation of high-molecular-weight salivary proteins on S-500 HR columns showed GalNAcbeta1-3Galalpha-O-ethyl-inhibitable binding to both mucin- and S-IgA-containing fractions. The presence of S-IgA in salivary pellicles formed in vivo on teeth was demonstrated by Western blot analysis of pellicle extracts with anti-IgA antibodies. Among strains representing A. naeslundii genospecies 1 and 2 and A. odontolyticus, only those of genospecies 1 with a particular adherence profile showed efficient GalNAcbeta1-3Galalpha-O-ethyl-inhibitable binding to S-IgA. Thus, oligosaccharides on S-IgA may promote bacterial aggregation (or adherence) and provide a mechanism by which S-IgA can interact with bacteria without prior immunological challenge.
authors.affiliation: Department of Cariology, Umeå University, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Bratt
authors.lastname: Borén
authors.forename: T
authors.initials: T
authors.lastname: Borén
authors.forename: N
authors.initials: N
authors.lastname: Str ömberg
mesh_terms: D000190:Actinomyces / Q000145:classification / Q000378:metabolism*; D000942:Antigens, Bacterial / Q000378:metabolism*; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000378:metabolism*; D001422:Bacterial Adhesion; D015153:Blotting, Western; D003126:Colostrum / Q000276:immunology; D003741:Dental Deposits / Q000378:metabolism; D044622:Dental Pellicle; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000378:metabolism*; D007143:Immunoglobulin Heavy Chains / Q000378:metabolism*; D007519:Isoantigens / Q000378:metabolism*; D007785:Lactose / Q000494:pharmacology; D008970:Molecular Weight; D009077:Mucins / Q000378:metabolism; D010306:Parotid Gland / Q000276:immunology; D019887:Peanut Agglutinin / Q000378:metabolism; D011485:Protein Binding; D012471:Salivary Proteins and Peptides / Q000378:metabolism
chemical_list: D000942:Antigens, Bacterial; D015295:Antigens, Tumor-Associated, Carbohydrate; D007071:Immunoglobulin A, Secretory; D007143:Immunoglobulin Heavy Chains; D007519:Isoantigens; D009077:Mucins; D019887:Peanut Agglutinin; D012471:Salivary Proteins and Peptides; C016467:Thomsen-Friedenreich antigen; D007785:Lactose