title: Regulatory and activated T cells in human Schistosoma haematobium infections.
abstract: Acquired immunity against helminths is characterised by a complex interplay between the effector Th1 and Th2 immune responses and it slowly manifests with age as a result of cumulative exposure to parasite antigens. Data from experimental models suggest that immunity is also influenced by regulatory T cells (Treg), but as yet studies on Treg in human schistosome infections are limited. This study investigated the relationship between schistosome infection intensity and the two cell populations regulatory T cells (TREG: CD4(+(dim))CD25(+(high))FOXP3(+)CD127(low)), and activated (Tact: CD4(+)CD25(+)FOXP3(-)) T cells in Zimbabweans exposed to Schistosoma haematobium parasites. Participants were partitioned into two age groups, young children (8-13 years) in whom schistosome infection levels were rising to peak and older people (14+ years) with declining infection levels. The relationship between Tact proportions and schistosome infection intensity remained unchanged with age. However Treg proportions rose significantly with increasing infection in the younger age group. In contrast Treg were negatively correlated to infection intensity in the older age group. The relative proportions of regulatory T cells differ significantly between young individuals in whom high infection is associated with an enhanced regulatory phenotype and older infected patients in whom the regulatory response is attenuated. This may influence or reflect different stages of the development of protective schistosome acquired immunity and immunopathogenesis.
authors.affiliation: Ashworth Laboratories, School of Biological Sciences, Institute for Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom. nnausch@staffmail.ed.ac.uk
authors.forename: Norman
authors.initials: N
authors.lastname: Nausch
authors.forename: Nicholas
authors.initials: N
authors.lastname: Midzi
authors.forename: Takafira
authors.initials: T
authors.lastname: Mduluza
authors.forename: Rick M
authors.initials: RM
authors.lastname: Maizels
authors.forename: Francisca
authors.initials: F
authors.lastname: Mutapi
mesh_terms: D000293:Adolescent; D000375:Aging / Q000276:immunology; D000818:Animals; D002648:Child; D005260:Female; D051858:Forkhead Transcription Factors / Q000378:metabolism; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D008297:Male; D012548:Schistosoma haematobium / Q000472:pathogenicity*; D012553:Schistosomiasis haematobia / Q000453:epidemiology / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D053645:Interleukin-2 Receptor alpha Subunit