RESISTANCE RANKING OF SOME COMMON INBRED MOUSE STRAINS TO MYCOBACTERIUM-TUBERCULOSIS AND RELATIONSHIP TO MAJOR HISTOCOMPATIBILITY COMPLEX HAPLOTYPE AND NRAMP1 GENOTYPE

Six common inbred strains of mice and their F-1 hybrids were examined for resistance to infection with the H37Rv strain of Mycobacterium tub erculosis. According to survival times after inoculation of 10(5) CFU intravenously (i.v.), the mice could be classified as being either hig hly susceptible (CBA, DBA/2. C3H, 129/SvJ) or highly resistant (BALB/c and C57BL/6). F-1 hybrids of susceptible and resistant strains were r esistant. Although an examination of a limited number of H-2 congenic strains showed that the H-2(k) haplotype could confer susceptibility o n a resistant strain, it was evident that non-major histocompatibility complex (MHC) genes were much more important. Resistant strains all p ossessed the susceptibility allele of the anti-microbial resistance ge ne, Nramp1. Results obtained with selected strains infected with 10(2) CFU of M. tuberculosis by aerosol agreed with the results obtained wi th mice infected i.v. The size of the bacterial inoculum was important in distinguishing between resistant and susceptible strains, in that a 10(7) inoculum overcame the resistance advantage of one strain over another.