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Leishmania major parasites reside and multiply in late endosomal compartments of host phagocytic cells. Immune control of Leishmania growth absolutely requires expression of inducible Nitric Oxide Synthase (iNOS/NOS2) and subsequent production of NO. Here, we show that CD11b+ CD11c+ Ly-6C+ MHC-II+ cells are the main iNOS-producing cells in the footpad(More)
Dendritic cells (DC) are described as "nature's adjuvant," since they have the capacity to sensitize T cells in vivo upon first encounter with the antigen. The potent accessory properties of DC appear to develop sequentially. In particular, the ability to process antigens and to sensitize native T cells develops in sequence, a process termed "maturation"(More)
The classical view of the Th1/Th2 paradigm posits that the pathogen nature, infectious cycle, and persistence represent key parameters controlling the choice of effector mechanisms operating during an immune response. Thus, efficient Th1 responses are triggered by replicating intracellular pathogens, while Th2 responses would control helminth infection and(More)
Brucella are facultative intracellular bacteria that chronically infect humans and animals causing brucellosis. Brucella are able to invade and replicate in a broad range of cell lines in vitro, however the cells supporting bacterial growth in vivo are largely unknown. In order to identify these, we used a Brucella melitensis strain stably expressing(More)
Cells of the dendritic cell (DC) lineage, by their unique ability to stimulate naive T cells, may be of crucial importance in the development of protective immune responses to Leishmania parasites. The aim of this study was to compare the impact of L. major infection on DCs in BALB/c (susceptible, developing Th2 responses), C57BL/6 (resistant, developing(More)
Viewed from a neo-Darwinian perspective , the main function of the metazoan immune system (IS) is to insure host integrity against invading microorganisms, which are only considered as selfish competitors that reduce the host's resources , inflict tissue damage, and ultimately compromise host fitness. Coevolution of the host and these competitors has been(More)
The germinative ventricular zone of embryonic brain contains neural lineage progenitor cells that give rise to neurons, astrocytes and oligodendrocytes. The ability to generate neurons persists at adulthood in restricted brain areas. During development, many growth factors exert their effects by interacting with tyrosine kinase receptors and activate the(More)
Protozoa and bacteria infect various types of phagocytic cells including macrophages, monocytes, dendritic cells and eosinophils. However, it is not clear which of these cells process and present microbial antigens in vivo and in which cellular compartments parasite peptides are loaded onto Major Histocompatibility Complex molecules. To address these(More)
The fitness gains resulting from development of the adaptive immune system (AIS) during evolution are still the subject of hot debate. A large random repertoire of antigenic receptors is costly to develop and could be the source of autoimmune reactions. And yet, despite their drawbacks, AIS-like systems seem to have been independently acquired in several(More)
Acquired immunity against infectious disease (AIID) has long been considered as strictly dependent on the B and T lymphocytes of the adaptive immune system. Consequently, AIID has been viewed as highly specific to the antigens expressed by pathogens. However, a growing body of data motivates revision of this central paradigm of immunology. Unrelated past(More)