image: Acute HIV infection initiates an inflammatory response that fosters replication of the virus, resulting in massive depletion of CD4+ T cells from the gut mucosa as well as upregulation of the enzyme, indoleamine 2,3-dioxygenase (IDO). Up-regulation of IDO, in turn, leads to the depletion of IL-17 expressing Th17 cells in viremic HIV patients (noncontrollers), resulting in progressive disruption of the mucosal barrier and increased translocation of bacterial products from the gut. These products feed into a positive feedback loop of continued local and systemic inflammation, reflected by increasing viral replication and progressive CD4+ T cell depletion. This image relates to an article that appeared in the May 19, 2010, issue of Science Translational Medicine, published by AAAS. The study, by Dr. David Favre of University of California, San Francisco in San Francisco, and National Immune Monitoring Laboratory, Montréal, QC, Canada, and colleagues, is titled, "Tryptophan Catabolism by Indoleamine 2,3-Dioxygenase 1 Alters the Balance of TH17 to Regulatory T Cells in HIV Disease." view more
Credit: [Image courtesy of Jeff Mold, David Favre, Daniel C. Douek, Jason M. Brenchly and Joseph M. McCune]