Expression of the Natural Resistance Gene (Lsh) in Wild Mice Infected Experimentally with Leishmania donovani or Salmonella typhimurium

Abstract

Leishmania species are obligate intracellular protozoan parasites of the host’s mononuclear phagocyte system. The particular tissue tropism of the parasite (cutaneous versus visceral) is determined largely by the species of leishmanial parasite but, within each species, a broad spectrum of disease profiles results from variations in the host’s ability either to control growth of the parasite population early in infection (Bradley 1979; Crocker, Blackwell & Bradley 1984a) and/or to mount an effective cell mediated immune response as the disease progresses (Skov & Twohy 1974; Rezai, Farrell & Soulsby 1980). In inbred mouse strains ability to control early proliferation of L. donovani in the viscera is determined by a single gene, Lsh, which segregates for dominant resistant and recessive susceptible alleles (Bradley 1974 & 1977) and maps to a position between Idh-1 and ln on mouse chromosome 1 (Bradley, Taylor, Blackwell, Evans & Freeman 1979). This gene is indistinguishable by traditional genetic analysis from the separately described genes, Ity and Bcg, which control early resistance and susceptibility to Salmonella typhimurium (Plant, Blackwell, O’Brien, Bradley & Glynn 1982) and Mycobacterium bovis (Skamene, Gros, Forget, Kongshavn, St. Charles & Taylor 1982). Functional studies also suggest that the genes are identical.