CLONING OF AN MYCOBACTERIUM-TUBERCULOSIS DNA FRAGMENT ASSOCIATED WITHENTRY AND SURVIVAL INSIDE CELLS

Mycobacterium tuberculosis infects one-third of the world's human popu lation. This widespread infection depends on the organism's ability to escape host defenses by gaining entry and surviving inside the macrop hage. DNA sequences of M. tuberculosis have been cloned; these confer on a nonpathogenic Escherichia coli strain an ability to invade HeLa c ells, augment macrophage phagocytosis, and survive for at least 24 hou rs inside the human macrophage. This capacity to gain entry into mamma lian cells and survive inside the macrophage was localized to two dist inct loci on the cloned M. tuberculosis DNA fragment.