Leishmania Promotes Its Own Virulence by Inducing Expression of the Host Immune Inhibitory Ligand CD200

Mauro Cortez et al., 2011, Cell Host & Microbe Journal9: 463–471

Speaker: Chiung-Chen Chou (周炯呈)                         Time: 14:00~15:00, May. 23, 2012

Commentator: Dr. Chih-LiHsu (胥直利老師)              Place: Room 601

Abstract

Leishmania is the protozoan parasite infects people that cause millions of cases each year in the world. The macrophage which involved in human innate immunity, infected by Leishmania will transform from inactive to active to impair intracellular microbes by antimicrobial mechanism. Nitric oxide synthase (NOS) is one of the antimicrobial mechanisms which expressed by macrophage. Inducible nitric oxide synthase (iNOS) will be detected in actived macrophage and characterized by a high-output production of NO. Many inhibitory receptors have been described on myeloid cells that involved in the control of host innate immune response. The cell surface glycoprotein-CD200R and its ligand-CD200 are one of the inhibitory ligand-receptor for inhibit iNOS expression. The author described L. amazonensis but not L. major infected wild type macrophages could induced CD200 signals that inhibit the iNOS expression of macrophage, this phenomenon promoting L.amazonensis own survival and virulence. And treated CD200^-/- macrophage model with CD200-Fc fusion proteins supported the intracellular replication of L. amazonensis and L. major. This study indicated that CD200-mediated iNOS inhibition promote parasite growth in macrophages.

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