Journal of Dental Research, Vol 78, 1238-1244, Copyright © 1999 by International & American Associations for Dental Research Online Journals

ARTICLES

Secretory immunoglobulin A heavy chain presents Galbeta1-3GalNAc binding structures for Actinomyces naeslundii genospecies 1

P. Bratt, D. Boren, T. Boren and N. Stromberg
Department of Cariology, Umea University, Sweden.

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 (Stromberg 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.

This article has been cited by other articles:

				B. Corthesy, H. R. Gaskins, and A. Mercenier Cross-Talk between Probiotic Bacteria and the Host Immune System J. Nutr., March 1, 2007; 137(3): 781S - 790S. [Abstract] [Full Text] [PDF]

				A. Prakobphol, F. Xu, V. M. Hoang, T. Larsson, J. Bergstrom, I. Johansson, L. Frangsmyr, U. Holmskov, H. Leffler, C. Nilsson, et al. Salivary Agglutinin, Which Binds Streptococcus mutans and Helicobacter pylori, Is the Lung Scavenger Receptor Cysteine-rich Protein gp-340 J. Biol. Chem., December 15, 2000; 275(51): 39860 - 39866. [Abstract] [Full Text] [PDF]