Interleukin-12 (IL-12) augments cytolytic activity of natural killer cells toward Mycobacterium tuberculosis-infected human monocytes.
We tested the impact of interleukin-12 (IL-12) and of cytotoxic leukocytes (particularly natural killer (NK) cells) from normal and HIV-1-infected subjects on lysis of human monocytes infected with Mycobacterium tuberculosis. Nylon wool nonadherent cells stimulated with interleukin-2 (IL-2) or with IL-12 developed significant killing activity against infected monocytes, with IL-12 being a superior stimulant on a molar basis. Cells of the CD16+ phenotype mediated most of the cytotoxicity against infected monocytes and this lytic activity was associated with a significant decrease in mycobacterial numbers. When peripheral blood mononuclear cells (PBMC) from HIV-1-infected subjects were examined, it was also found that IL-12 very significantly increased lytic activity against M. tuberculosis-infected cells. Moreover, purified NK cells from normal volunteers or from HIV-1-infected subjects were shown to have elevated lytic activity against M. tuberculosis-infected monocytes after IL-2 or IL-12 stimulation. These data suggest an important involvement of NK cells and their activating stimuli (particularly IL-12) in host resistance to tuberculosis.
Denis
M
M
Pulmonary Research Unit, Faculty of Medicine, University of Sherbrooke, Quebec, Canada.
D017088:AIDS-Related Opportunistic Infections / Q000150:complications / Q000276:immunology / Q000382:microbiology; D003602:Cytotoxicity, Immunologic; D015497:HIV-1; D006801:Humans; D066298:In Vitro Techniques; D018664:Interleukin-12; D007376:Interleukin-2 / Q000494:pharmacology; D007378:Interleukins / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000276:immunology*; D009000:Monocytes / Q000276:immunology* / Q000382:microbiology; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D014397:Tuberculosis, Pulmonary / Q000150:complications / Q000276:immunology / Q000382:microbiology
D007376:Interleukin-2; D007378:Interleukins; D018664:Interleukin-12