title: Regulation of naturally acquired mucosal immunity to Streptococcus pneumoniae in healthy Malawian adults and children.
abstract: Worldwide, invasive pneumococcal disease caused by Streptococcus pneumoniae is most common in young children. In adults, disease rates decline following intermittent colonization and the acquisition of naturally acquired immunity. We characterized mucosal and systemic pneumococcal-specific T-cell responses in African children and adults who contend with intense rates of colonization, up to 100% and 60% respectively. We find most Malawian children have high pneumococcal-specific T-cell responses in tonsil tissue and peripheral blood. In addition, frequent commensalism generates CD25(hi) (Tregs) which modulate mucosal pneumococcal-specific T-cell responses in some children and ≥50% of adults. We propose that immune regulation may prolong pneumococcal colonization and predispose vulnerable individuals to disease.
authors.affiliation: Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi. sarah.glennie@liverpool.ac.uk
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Glennie
authors.forename: Dominic
authors.initials: D
authors.lastname: Banda
authors.forename: Wakisa
authors.initials: W
authors.lastname: Mulwafu
authors.forename: Rose
authors.initials: R
authors.lastname: Nkhata
authors.forename: Neil A
authors.initials: NA
authors.lastname: Williams
authors.forename: Robert S
authors.initials: RS
authors.lastname: Heyderman
mesh_terms: D056704:Adaptive Immunity / Q000276:immunology*; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure; D006262:Health; D006801:Humans; D018928:Immunity, Mucosal; D007223:Infant; D008295:Malawi; D014066:Palatine Tonsil / Q000276:immunology / Q000382:microbiology; D011008:Pneumococcal Infections / Q000097:blood / Q000276:immunology; D013045:Species Specificity; D013296:Streptococcus pneumoniae / Q000276:immunology* / Q000502:physiology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000382:microbiology; D055815:Young Adult