Immunological and bacteriological basis for vaccination against dental caries in rhesus monkeys

Abstract

A REPRODUCIBLE model for dental caries has been established in rhesus monkeys¹. The development of caries is comparable to that found in man because caries is induced by maintaining the animals on a human type of diet, this is associated with an overgrowth of a naturally acquired Streptococcus mutans and caries develops in teeth that are morphologically similar to human teeth. The incidence of smooth surface caries was reduced by subcutaneous or submucous immunisation with a heat-killed Strep. mutans in Freund's incomplete adjuvant (FIA)². Protection has been correlated predominantly with the rate of development of serum complement fixing antibodies to a hydroxyl apatite fraction of the culture supernatant (HACS) of Strep. mutans. The aims of this investigation were to attempt to elucidate the mechanism of prevention of dental caries in rhesus monkeys by immunisaion with a monkey passaged Strep. mutans. The relative effects of saliva and crevicular fluid on Strep. mutans were tested by developing a differential sampling technique across the plaque and the adjacent saliva and crevicular fluid. This revealed that the very low caries score in the immunised animals was correlated with serum antibodies and with a reduction in the number of Strep. mutans in crevicular fluid and the adjacent bacterial plaque zone.