Genetic Control of Resistance to Intracellular Parasites

"The phenotypic expression of the Bcg locus at the cellular level was investigated in vivo: the cell responsible for early resistance was found not to be a T-cell and most probably not a B cell. The genetically-controlled mechanism of defense proved to be resistant to 950 rads of X-irradiation and susceptible to the toxic effect of silica. The reticuloendothelial system of both Bcg('r) and Bcg('s) strains showed an equal ability to clear a bacterial inoculum from their blood and these animals were also comparable in the intensity of the inflammatory response to an intraperitoneal inoculum of BCG. Explanted pleural and peritoneal resident macrophages supported equally well, independently of their genotype, the intracellular growth of various strains of mycobacteria in vitro." --