Immunoregulation by indoleamine 2,3-dioxygenases in tuberculosis

Narrative A barrier to developing effective strategy for control of disease caused by Mycobacterium tuberculosis (Mtb) is the exceptional ability of this pathogen to evade host immune responses. We propose that Mtb circumvents some immune defenses by activating an immunosuppressive pathway controlled by a host enzyme called indoleamine 2,3-dioxygenase (IDO). We have found that IDO contributes to the control of the pathological process in Mtb infection, and likely promotes the transmission of the bacteria. Studies will be carried out to gain a full understanding of how IDO regulates the development of immunopathology in an Mtb-infected host, and the information obtained will be applied to strategies for improving vaccination and host-directed therapies against this infection.