title: [Immunity and defenses against infection].
abstract: The roles of the immune system are to protect the host from the various pathogenic agents and to ensure the tolerance to self. It brings into play two categories of processes which appeared successively during the evolution, innate immunity and adaptive immunity. The actors of these two processes will be recruited in a sequential way in the event of infection by a micro-organism.
authors: Centre détude des déficits immunitaires, hôpital Necker-Enfants-Malades, 75015 Paris. picardc@necker.fr
authors: Capucine
authors: C
authors: Picard
mesh_terms: D000917:Antibody Formation; D006801:Humans; D007109:Immunity; D007111:Immunity, Cellular; D007113:Immunity, Innate; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D007239:Infections / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D051193:Toll-Like Receptors / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha