%0 Journal Article
%T The role of indoleamine 2, 3 dioxygenase in regulating host immunity to leishmania infection
%A Levi HC Makala
%J Journal of Biomedical Science
%D 2012
%I BioMed Central
%R 10.1186/1423-0127-19-5
%X Chronic microbial infections, such as tuberculosis, AIDS, malaria and leishmaniasis, are a global health problem due to poor preventative health care in many developing countries, and lack of effective vaccines and drugs to prevent or clear chronic infections. Chronic infections pose an immunological paradox because pathogens persist in immune-competent hosts that, in principle, ought to mount effective immune responses leading to pathogen clearance. The fact that chronic infections persist under such circumstances suggests that pathogens exploit host immuno-regulatory mechanisms to protect themselves (and infected cells) by evading or actively suppressing host immunity. This perspective provides the rationale for identifying natural (host) immune-regulatory mechanisms exploited by pathogens and using this new knowledge to improve therapy.This review summarizes new insights that are emerging from recent studies, focusing on why Leishmania persistence is achieved, and the other on DC subsets. These may well be inter-connected. It is a well-known fact that persistence is a hall mark of many parasitic infections. In this review, we attempt to uncover a novel mechanism by which Leishmania parasites circumvent effector T cell responses through the induction of indoleamine 2,3-dioxygenase (IDO) expression. Dendritic cell subsets (DC) are central in regulating immunity, often establishing immunologically privileged tissue micro environments through the induction of of T regulatory cells. One key concept is that only certain subsets of DCs seem competent to express IDO, at least at the level of functional immunoregulation. The factors that influence the development and tissue distribution of these IDO-competent DCs have yet to be determined. Unanswered issues include whether the different IDO-competent subsets arise from one or multiple lineages; and which signals during differentiation determine their ability to express IDO. One key mechanism that mediates many DC regulato
%K Leishimania major
%K Indoleamine 2
%K 3-dioxygenase
%K Mice
%K Leishmaniasis
%K Host Immunity
%K 1-methyl-d-tryptophan
%K plasmacytoid dendritic cell
%K regulatory T cell
%K draining lymph node
%U http://www.jbiomedsci.com/content/19/1/5