title: Impairment of T cell function in parasitic infections.
abstract: In mammals subverted as hosts by protozoan parasites, the latter and/or the agonists they release are detected and processed by sensors displayed by many distinct immune cell lineages, in a tissue(s)-dependent context. Focusing on the T lymphocyte lineage, we review our present understanding on its transient or durable functional impairment over the course of the developmental program of the intracellular parasites Leishmania spp., Plasmodium spp., Toxoplasma gondii, and Trypanosoma cruzi in their mammalian hosts. Strategies employed by protozoa to down-regulate T lymphocyte function may act at the initial moment of naïve T cell priming, rendering T cells anergic or unresponsive throughout infection, or later, exhausting T cells due to antigen persistence. Furthermore, by exploiting host feedback mechanisms aimed at maintaining immune homeostasis, parasites can enhance T cell apoptosis. We will discuss how infections with prominent intracellular protozoan parasites lead to a general down-regulation of T cell function through T cell anergy and exhaustion, accompanied by apoptosis, and ultimately allowing pathogen persistence.
authors.affiliation: CNRS FRE 3235, Université Paris Descartes, Paris, France ; Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors.forename: Vasco
authors.initials: V
authors.lastname: Rodrigues
authors.affiliation: Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal ; Departamento de Ciências Biológicas, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal.
authors.forename: Anabela
authors.initials: A
authors.lastname: Cordeiro-da-Silva
authors.affiliation: CNRS FRE 3235, Université Paris Descartes, Paris, France.
authors.forename: Mireille
authors.initials: M
authors.lastname: Laforge
authors.affiliation: Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors.forename: Ali
authors.initials: A
authors.lastname: Ouaissi
authors.affiliation: Département de Biologie, Faculté des Sciences Aîn-Chock, Université Hassan II-Casablanca, Casablanca, Maroc.
authors.forename: Khadija
authors.initials: K
authors.lastname: Akharid
authors.affiliation: Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Silvestre
authors.affiliation: CNRS FRE 3235, Université Paris Descartes, Paris, France ; Université Laval, Centre de Recherche en Infectiologie, Québec, Canada.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Estaquier
mesh_terms: D000818:Animals; D006790:Host-Parasite Interactions / Q000276:immunology*; D006801:Humans; D018448:Models, Immunological; D010271:Parasites / Q000276:immunology / Q000472:pathogenicity / Q000502:physiology; D010272:Parasitic Diseases / Q000276:immunology / Q000469:parasitology; D013601:T-Lymphocytes / Q000276:immunology / Q000469:parasitology