title: [Host reactions against bacteria. Application to pneumococcal infections].
abstract: Pneumococcal infection remains a public health problem, because of its important incidence, as well for pneumonias (2 cases per 1,000 persons per year) as for bacteremias (0.5% among hospitalized patients). The fatality rate in the bacteremic cases is 37.3% and reaches 89% in the fulminant sepsis cases, which are observed especially in splenectomized patients: the spleen takes part in the host defences against Streptococcus pneumoniae, together with the phagocytosis, the antibody production and the complement activation, essentially through the alternative complement pathway-activated C3b. Bacterial opsonization remains the fundamental mechanism of the host defence in the early stages of the pneumococcal infection.
mesh_terms: D000907:Antibodies, Bacterial / Q000096:biosynthesis; D003170:Complement Pathway, Alternative; D006801:Humans; D010587:Phagocytosis; D011008:Pneumococcal Infections / Q000276:immunology* / Q000401:mortality; D018805:Sepsis / Q000276:immunology; D013154:Spleen / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000472:pathogenicity; D014774:Virulence
chemical_list: D000907:Antibodies, Bacterial
vernacular_title: Réactions de l'hôte contre la bactérie. Applications aux infections pneumococciques.