blood group antigens
Springer Online Journal Archives 1860-2000
Abstract Streptococcus mutans is a major etiological agent in dental caries. Salivary agglutinin is one of the main salivary components binding to S.mutans. To learn more about the interaction of salivary agglutinin with S.mutans, parotid, submandibular, sublingual and palatal saliva samples were incubated with S. mutans suspension. Both depleted saliva samples and bacterial extracts were analyzed by SDS-PAGE and immunoblotting. Salivary agglutinin was present in all types of glandular saliva and in all cases bound to S.mutans, also to PC337C, a P1− mutant of S.mutans. Agglutinin was separated by SDS-PAGE under reducing and non-reducing conditions and then transferred to nitrocellulose. Non-reduced agglutinin bound S.mutans, but reduced agglutinin did not. Adhesion of S.mutans to agglutinin-coated microplates was inhibited by amine-containing components, 1 M NaCl or KCl and EDTA. Adhesion decreased with decreasing pH with no adhesion below pH 5.0. These data suggest that calcium-dependent electrostatic interactions play a role in binding. By immunoblotting was demonstrated that blood group antigens and Lewis antigens were present on agglutinin. Synthetic blood group antigens and Lewis antigens covalently coupled to polyacrylamide were tested for binding to S.mutans. Only Lea(Galβ1,3(Fucα1,4)GlcNAc) bound to S.mutans, whereas the blood group antigens Leb, Lex, Ley, H1, H2, A, B and sialylated Lea did not. Lea without galactose (Fucα1,4GlcNAc) still bound to S. mutans, but Lea without fucose (Galβ1,3GlcNAc) did not. Binding of agglutinin to S. mutans was not inhibited by Lea. In conclusion, S. mutans can bind to Lea carbohydrate epitopes in which the fucose is an essential residue. Lea carbohydrate epitopes are present on salivary agglutinin but play no major role in binding.
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