IL-26 contributes to host defense against intracellular bacteria.
IL-26 is an antimicrobial protein secreted by Th17 cells that has the ability to directly kill extracellular bacteria. To ascertain whether IL-26 contributes to host defense against intracellular bacteria, we studied leprosy, caused by the obligate intracellular pathogen Mycobacterium leprae, as a model. Analysis of leprosy skin lesions by gene expression profiling and immunohistology revealed that IL-26 was more strongly expressed in lesions from the self-limited tuberculoid compared with expression in progressive lepromatous patients. IL-26 directly bound to M. leprae in axenic culture and reduced bacteria viability. Furthermore, IL-26, when added to human monocyte-derived macrophages infected with M. leprae, entered the infected cell, colocalized with the bacterium, and reduced bacteria viability. In addition, IL-26 induced autophagy via the cytoplasmic DNA receptor stimulator of IFN genes (STING), as well as fusion of phagosomes containing bacilli with lysosomal compartments. Altogether, our data suggest that the Th17 cytokine IL-26 contributes to host defense against intracellular bacteria.
['Dang|Angeline Tilly|AT|', 'Teles|Rosane Mb|RM|', 'Weiss|David I|DI|', 'Parvatiyar|Kislay|K|', 'Sarno|Euzenir N|EN|', 'Ochoa|Maria T|MT|', 'Cheng|Genhong|G|', 'Gilliet|Michel|M|', 'Bloom|Barry R|BR|', 'Modlin|Robert L|RL|']
D001343:Autophagy D016207:Cytokines D020869:Gene Expression Profiling D006801:Humans D007378:Interleukins D015440:Leprosy, Lepromatous D015441:Leprosy, Tuberculoid D008247:Lysosomes D008264:Macrophages D009000:Monocytes D009166:Mycobacterium leprae D009169:Mycobacterium tuberculosis D010588:Phagosomes D011994:Recombinant Proteins D015398:Signal Transduction D058504:Th17 Cells
Cellular immune response Immunology Infectious disease