Infection genomics:: Nramp1 as a major determinant of natural resistance to intracellular infections

The scope of the tuberculosis (TB) epidemic in the world today is enormous, with about 30 million active cases. Current research into preventing the spread of TB is focused on development of new drugs to inactivate Mycobacterium tuberculosis, the causative agent of TB, as well as on identifying the critical steps of host defense to infection with Mycobacteria, which might also yield therapeutic targets. Our infection genomics approach toward the latter strategy has been to isolate and characterize a mouse gene, Beg (Nramp1), which controls natural susceptibility to infection with Mycobacteria, as well as Salmonella and Leishmania. Through comparative genomics, we have identified the homologous human NRAMP1 gene, alleles of which are now being used for tests of linkage with TB and leprosy.