Abstract
Susceptibility of mice to the establishment of infection after exposure to mycobacteria is controlled by a single, dominant, autosomal gene: the Bcg gene. It is located on the centromeric portion of chromosome 1 within a linkage group that shows structural homology with a conserved region of human chromosome 2. The Bcg gene regulates directly the process of T cell-independent macrophage activation for antimycobacterial function and, indirectly, the magnitude and the quality of specific immune response to mycobacterial antigens.