title: Myd88-dependent in vivo maturation of splenic dendritic cells induced by Leishmania donovani and other Leishmania species.
abstract: The usual agent of visceral leishmaniasis in the Old World is Leishmania donovani, which typically produces systemic diseases in humans and mice. L. donovani has developed efficient strategies to infect and persist in macrophages from spleen and liver. Dendritic cells (DC) are sentinels of the immune system. Following recognition of evolutionary conserved microbial products, DC undergo a maturation process and activate antigen-specific naïve T cells. In the present report we provide new insights into how DC detect Leishmania in vivo. We demonstrate that in both C57BL/6 and BALB/c mice, systemic injection of L. donovani induced the migration of splenic DC from marginal zones to T-cell areas. During migration, DC upregulated the expression of major histocompatibility complex II and costimulatory receptors (such as CD40, CD80, and CD86). Leishmania-induced maturation requires live parasites and is not restricted to L. donovani, as L. braziliensis, L. major, and L. mexicana induced a similar process. Using a green fluorescent protein-expressing parasite, we demonstrate that DC undergoing maturation in vivo display no parasite internalization. We also show that L. donovani-induced DC maturation was partially abolished in MyD88-deficient mice. Taken together, our data suggest that Leishmania-induced DC maturation results from direct recognition of Leishmania by DC, and not from DC infection, and that MyD88-dependent receptors are implicated in this process.
authors.affiliation: Laboratory of Animal Physiology, Institut de Biologie et de Médecine Moléculaire, Université Libre de Bruxelles, Gosselies, Belgium.
authors.forename: Carl
authors.initials: C
authors.lastname: De Trez
authors.forename: Maryse
authors.initials: M
authors.lastname: Brait
authors.forename: Oberdan
authors.initials: O
authors.lastname: Leo
authors.forename: Tony
authors.initials: T
authors.lastname: Aebischer
authors.forename: Fabiola Aguilar
authors.initials: FA
authors.lastname: Torrentera
authors.forename: Yves
authors.initials: Y
authors.lastname: Carlier
authors.forename: Eric
authors.initials: E
authors.lastname: Muraille
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000943:Antigens, Differentiation / Q000502:physiology*; D001402:B-Lymphocytes / Q000502:physiology; D002465:Cell Movement; D003713:Dendritic Cells / Q000469:parasitology / Q000502:physiology*; D005260:Female; D007891:Leishmania / Q000502:physiology*; D007893:Leishmania donovani / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D053594:Myeloid Differentiation Factor 88; D011956:Receptors, Cell Surface / Q000502:physiology; D011971:Receptors, Immunologic / Q000502:physiology*; D013154:Spleen / Q000166:cytology*; D013601:T-Lymphocytes / Q000502:physiology; D051193:Toll-Like Receptors
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000943:Antigens, Differentiation; D008562:Membrane Glycoproteins; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; D051193:Toll-Like Receptors