Host genotype, pathogenic challenge and periodontal bone loss in the mouse.

Periodontal bone loss was induced in mice of different genotypes by oral inoculation with Actinomyces viscosus. Relatively high bone loss occurred in the mutant X-linked immune deficiency, implicating the humoral immune system. Maximum bone loss was always associated with inoculations of 1.6 x 10(7) colony forming units (c.f.u.), while inoculations of 1.6 x 10(6) or 1.6 x 10(9) c.f.u. resulted in bone loss little different from that in uninoculated controls. This 1000-fold range in inoculum size was not reflected in the number of A. viscosus organisms recovered from the molar teeth at the end of the experimental period, suggesting that differences in bone loss stemmed from the host response to the initial inoculum.