Genetic control of natural resistance to Mycobacterium bovis (BCG) in mice.

Mice of 12 inbred strains infected i.v. with Mycobacterium bovis (BCG) exhibited 2 distinct patterns of response as determined by the degree of BCG burden in the spleens of animals at 3 wk after infection with 10(4) viable bacilli: susceptible (C57BL/6J and related sublines, BALB/c and DBA/1J) and resistant (A/J, C3H/HeCr, DBA/2J, CBA/J, C57Br, AKR). Mendelian analysis of this trait on segregating backcross and F2 populations derived from the mating of resistant and susceptible progenitors was compatible with the hypothesis that resistance to BCG is controlled by a single, dominant, autosomal gene, which is being given the designation Bcg. The product of the Bcg gene was found to influence the early phase of host response resulting in the genetic advantage of the resistant host being demonstrable as early as 24 hr after infection.