title: Commonly invasive serotypes of Streptococcus pneumoniae trigger a reduced innate immune response compared with serotypes rarely responsible for invasive infection.
abstract: Although there are more than 90 serotypes of Streptococcus pneumoniae (or pneumococcus), it is not understood why a small number of serotypes account for most invasive infections. To investigate the human innate immune response triggered by different pneumococcal serotypes, monocyte-derived macrophages were exposed to a group of commonly and rarely invasive pneumococcal clinical isolates and tumor necrosis factor (TNF)-alpha production was measured. Commonly invasive pneumococcal serotypes triggered significantly less TNF-alpha production than serotypes rarely responsible for invasive infection (P<0.004). These data indicate that one factor influencing the invasive potential of a pneumococcal serotype is the magnitude of innate immune-mediated TNF-alpha production triggered by exposure to the organism and suggest that the integrated host response generated against commonly invasive pneumococcal serotypes may be less effective than the response directed against rarely invasive serotypes.
authors.affiliation: Department of Pediatrics, Division of Infectious and Immunological Diseases, BC Children's Hospital and Child & Family Research Institute, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Thomas S T
authors.initials: TS
authors.lastname: Burgess
authors.forename: Aaron F
authors.initials: AF
authors.lastname: Hirschfeld
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Tyrrell
authors.forename: Julie A
authors.initials: JA
authors.lastname: Bettinger
authors.forename: Stuart E
authors.initials: SE
authors.lastname: Turvey
mesh_terms: D000293:Adolescent; D002460:Cell Line; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology; D007223:Infant; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D011008:Pneumococcal Infections / Q000276:immunology* / Q000382:microbiology*; D013296:Streptococcus pneumoniae / Q000276:immunology* / Q000472:pathogenicity; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
chemical_list: D014409:Tumor Necrosis Factor-alpha