Identification of a Linkage Group Including the Bcg Gene by Restriction Fragment Length Polymorphism Analysis

Abstract

Inbred strains of mice greatly differ in their ability to control the proliferation of Mycobacterium bovis (BCG) in their reticuloendothelial organs (liver and spleen, reviewed by Skamene, 1983) and can be classified into two non-overlapping groups as resistant and susceptible to the infection. This difference in susceptibility is most evident when mice are injected intravenously with a low dose (10,000 bacilli) of live BCG and the number of colony forming units (CFU) in the spleen of the infected animals is determined 3 weeks later: susceptible animals show CFU counts 100 to a 1000 fold higher than their resistant counterparts. A kinetic analysis of bacterial growth revealed that the difference in bacterial load is due to a limited ability of susceptible mice to control the growth of the bacteria in the initial phase of the infection. A systematic typing of inbred mouse strains showed that approximately half of the strains were either resistant or susceptible while none of the investigated strains showed a pattern of intermediate bacterial growth (Forget et al. 1981) .