<原著>耳下腺唾液画分に対するStreptococcus mutans Ingbritt株の付着性とAntigen Bとの結合性について

The present study investigated the relationship between the components in parotid saliva that promote the adherence of Streptococcus mutans to hydroxyapatite (HA) and bind with Antigen B. Parotid saliva was fractionated into three fractions with an ultrafiltration apparatus using three kinds of ultrafilter paper with pore sizes of 50,000, 10,000, and 1,000, designated 50K UP, 10K UP and 1K UP fractions, respectively. Protein patterns on SDS-PAGE indicated that the 50K UP fraction contained species with molecular weights (Mw) above 50,000, the 10K UP fraction was mainly from Mw 25,000 to Mw 10,000, and the 1K UP fraction contained mainly proteins below Mw 20,000. S. mutans Ingbritt adhered to hydroxyapatite coated with these three fractions. The 1K UP, the lowest molecular weight, was applied to a Sephadex G-75 column and eluted with H_20. Two protein bands of Mw 14,400 and 16,500 were observed in the fractions to which S. mutans ingbritt adhered when coating HA, but not in the fractions to which S. mutans did not adhere. Although Antigen B bound to many parotid saliva components on immunoblot, it did not bind to these two components. The observations on immunoblot did not show whether these two components are related to the binding of Antigen B only when the components change to suitable conformations. It is suggested that nonspecific binding property of Antigen B may contain a heavy hydrophobic region anchor which is usually buried in the cell wall of S. mutans