Some Immunochemical Properties of Dextransucrase and Invertase from Streptococcus mutans

Abstract

Dextransucrase and invertase of some strains of Streptococcus mutans were examined by immunodiffusion with antisera against enzymes purified from strain HS-6 (Bratthall's serotype a). Both antisera cross-reacted with crude enzyme preparations from the other serotype a (strains HS-1 and AHT) and d organisms (strains KIR, OMZ176, and OMZ65) but not with those from serotype b (strains FA-1 and BHT) or c organisms (strains GS-5, Ingbritt, and NCTC 10449). Based upon the antiserum used, the orders of antigenic similarity of the cross-reacting enzymes to the HS-6 enzymes were HS-6 > HS-1 > AHT = KIR = OMZ176 = OMZ65 for dextransucrase and HS-6 = HS-1 > AHT = KIR = OMZ176 = OMZ65 for invertase. It was found that the enzymes from serotype a organisms were not always antigenically homogeneous, as seen between strains HS-6, HS-1, or AHT for dextransucrase, and between the HS group and strain AHT for invertase. Antiserum against the HS-6 dextransucrase markedly inhibited the heterologous dextransucrases of serotype a organisms with the exception of strain HS-1 and d organisms, with or without the addition of dextran.

Streptococcus mutans dextransucrase: stimulation by phospholipids from human sera and oral fluids

“…During many studies designed to measure antibodies directed against S. mutans dextransucrase preparations, it has been consistently ob-served that control and sometimes immune sera caused an elevation rather than an inhibition of glucan production from sucrose (4,9,10,20,22,27). Based on studies with sera and oral fluids from rats, Burckhardt and Guggenheim (4) proposed that there were sites on the S. mutans dextransucrase which could interact with molecules in the fluids and enhance glucan production.…”

“…Enhanced glucan production results from an increase in the velocity of polymerization of the glucosyl moiety of sucrose due to a high affinity interaction between phospholipid and a site on the enzyme which appears to be distinct from either the glucosyl donor or glucosyl acceptor sites. We have proposed (28) that the observed stimulation of dextransucrase activity by control and/or immune sera and oral fluids from monkeys (27), rabbits (9,10,20,22), and rats (4) is due to the presence of stimulatory phospholipids in these materials.…”

Serotype‐Dependent Inhibition of Glucan Synthesis and Cell Adherence of Streptococcus mutans by Antibody against Glucosyltransferase of Serotype e S. mutans

“…Antibodies against GTase(s) inhibit enzyme activity (1,6,7,9,10,21,23,35) and result in the reduction of experimental caries of S. mutans in rats (37). 5. mutans has been classified into seven serotypes (3,14,15,31) of which immunological specificity is based on the cell wall polysaccharide (12,17,22,23,26,27,40).…”

Characterization of an anti-glucosyltransferase serum specific for insoluble glucan synthesis by Streptococcus mutans

“…Initial studies with whole cell antisera and antiserum to crude enzyme preparations have reported inhibition of total or cell-associated glucan synthesis and inhibition of cell adher- ence to wire and glass surfaces (6,10,22,27). Fukui et al have prepared an antiserum to a highly purified a-1,6-glucan:n-fructose 2-glucosyltransferase and utilized it to examine crossreactions among the enzymes synthesizing soluble glucans from the various serotypes of S. mutans (9). The present report describes an antiserum specific for the glucosyltransferases which synthesize insoluble glucans.…”