Resistance and Susceptibility of Mice to Bacterial Infection. IV. Genetic and Cellular Basis of Resistance to Chronic Infection with Brucella abortus

Abstract

The number of Brucella abortus strain 19 organisms in the spleens of CBA/H mice peaked two weeks after intravenous injection of 5 × 10⁵ organisms. With the onset of specific cell-mediated immunity, 90070 of the bacteria were killed, but ∼10⁶ bacteria persisted up to seven weeks after infection. In contrast, in BALB/c, C57BL/1O, and BlOBr mice, bacterial numbers peaked at two weeks but decreased steadily with the onset of bactericidal activity. In all strains, clearance of bacteria from the liver was relatively efficient. The course of infection in (CBA/H × BALB/c) F₁ mice was similar to that in CBA/H mice, indicating that the mechanism(s) leading to slower recovery from infection was dominant. The H-2 haplotype of the mice did not influence the rate of recovery from infection. The use of backcross mice showed that multiple genes were involved. In bone marrow-chimeric mice, resistance was determined by the genome of the bone marrow donor, not that of the host.