MULTIPLE CHANGES IN CELL-WALL ANTIGENS OF ISOGENIC MUTANTS OF STREPTOCOCCUS-MUTANS

Isogenic mutants of Streptococcus mutans LT11, deficient in the produc tion of the wall-associated protein antigens A and B, were generated b y recombinant DNA technology. The hydrophobicity, adherence, and aggre gation of the mutants were compared with those of the parent strain. T hese studies indicated that hydrophobicity, adherence, and saliva- or sucrose-induced aggregation were unaltered in the A- mutant but that h ydrophobicity and adherence to saliva-coated hydroxylapatite were grea tly reduced in the B- mutant whilst sucrose-dependent adherence and ag gregation were increased. To determine whether these changes correlate d with changes in the mutated gene product alone, the levels of a numb er of cell wall antigens were determined in each of the mutants. The l oss of antigen A resulted in significantly reduced levels of wall-asso ciated lipoteichoic acid, and loss of antigen B resulted in reductions in both antigen A and lipoteichoic acid. Data presented here thus sug gest that changes in the expression of one wall antigen can have a dra matic effect on the levels of others.