title: IL-10 from CD4CD25Foxp3CD127 adaptive regulatory T cells modulates parasite clearance and pathology during malaria infection.
abstract: The outcome of malaria infection is determined, in part, by the balance of pro-inflammatory and regulatory immune responses. Failure to develop an effective pro-inflammatory response can lead to unrestricted parasite replication, whilst failure to regulate this response leads to the development of severe immunopathology. IL-10 and TGF-beta are known to be important components of the regulatory response, but the cellular source of these cytokines is still unknown. Here we have examined the role of natural and adaptive regulatory T cells in the control of malaria infection and find that classical CD4+CD25(hi) (and Foxp3+) regulatory T cells do not significantly influence the outcome of infections with the lethal (17XL) strain of Plasmodium yoelii (PyL). In contrast, we find that adaptive IL-10-producing, CD4+ T cells (which are CD25-, Foxp3-, and CD127- and do not produce Th1, Th2, or Th17 associated cytokines) that are generated during both PyL and non-lethal P. yoelii 17X (PyNL) infections are able to down-regulate pro-inflammatory responses and impede parasite clearance. In summary, we have identified a population of induced Foxp3- regulatory (Tr1) T cells, characterised by production of IL-10 and down regulation of IL-7Ralpha, that modulates the inflammatory response to malaria.
authors.affiliation: Immunology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Kevin N
authors.initials: KN
authors.lastname: Couper
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Blount
authors.forename: Mark S
authors.initials: MS
authors.lastname: Wilson
authors.forename: Julius C
authors.initials: JC
authors.lastname: Hafalla
authors.forename: Yasmine
authors.initials: Y
authors.lastname: Belkaid
authors.forename: Masahito
authors.initials: M
authors.lastname: Kamanaka
authors.forename: Richard A
authors.initials: RA
authors.lastname: Flavell
authors.forename: J Brian
authors.initials: JB
authors.lastname: de Souza
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Riley
mesh_terms: D000818:Animals; D015704:CD4 Antigens / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D015536:Down-Regulation; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D006790:Host-Parasite Interactions; D016753:Interleukin-10 / Q000378:metabolism*; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism*; D053699:Interleukin-7 Receptor alpha Subunit / Q000378:metabolism*; D008288:Malaria / Q000276:immunology* / Q000469:parasitology; D051379:Mice; D010967:Plasmodium yoelii / Q000276:immunology* / Q000472:pathogenicity; D051381:Rats; D020395:Receptors, Interleukin-7 / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D015704:CD4 Antigens; D016207:Cytokines; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D053645:Interleukin-2 Receptor alpha Subunit; D053699:Interleukin-7 Receptor alpha Subunit; D020395:Receptors, Interleukin-7; C415350:interleukin-7 receptor, alpha chain; D016753:Interleukin-10