A BACTERIAL CYTOKINE

Viable cells of Micrococcus luteus secrete a factor, which promotes th e resuscitation and growth of dormant, nongrowing cells of the same or ganism. The resuscitation-promoting factor (Rpf) is a protein, which h as been purified to homogeneity. In picomolar concentrations, it incre ases the viable cell count of dormant M. luteus cultures at least 100- fold and can also stimulate the growth of viable cells. Rpf also stimu lates the growth of several other high G+C Gram-positive organisms, in cluding Mycobacterium ar avium, Mycobacterium bovis (BCG), Mycobacteri um kansasii, Il Mycobacterium smegmatis, and Mycobacterium tuberculosi s, Similar genes are widely distributed among high G+C Gram-positive b acteria; genome sequencing has uncovered examples in Mycobacterium lep rae and dib. tuberculosis and others have been detected by hybridizati on in Mb. smegmatis, Corynebacterium glutamicum, and Streptomyces spp, The mycobacterial gene products may provide different targets for the detection and control of these important pathogens. This report is th us a description of a proteinaceous autocrine or paracrine bacterial g rowth factor or cytokine.