title: Regulatory T-cell expansion during chronic viral infection is dependent on endogenous retroviral superantigens.
abstract: Regulatory T cells (Treg) play critical roles in the modulation of immune responses to infectious agents. Further understanding of the factors that control Treg activation and expansion in response to pathogens is needed to manipulate Treg function in acute and chronic infections. Here we show that chronic, but not acute, infection of mice with lymphocytic choriomeningitis virus results in a marked expansion of Foxp3(+) Treg that is dependent on retroviral superantigen (sag) genes encoded in the mouse genome. Sag-dependent Treg expansion was MHC class II dependent, CD4 independent, and required dendritic cells. Thus, one unique mechanism by which certain infectious agents evade host immune responses may be mediated by endogenous Sag-dependent activation and expansion of Treg.
authors.affiliation: Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: George A
authors.initials: GA
authors.lastname: Punkosdy
authors.forename: Melissa
authors.initials: M
authors.lastname: Blain
authors.forename: Deborah D
authors.initials: DD
authors.lastname: Glass
authors.forename: Mary M
authors.initials: MM
authors.lastname: Lozano
authors.forename: Leigh
authors.initials: L
authors.lastname: O'Mara
authors.forename: Jaquelin P
authors.initials: JP
authors.lastname: Dudley
authors.forename: Rafi
authors.initials: R
authors.lastname: Ahmed
authors.forename: Ethan M
authors.initials: EM
authors.lastname: Shevach
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D002908:Chronic Disease; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology; D020077:Endogenous Retroviruses / Q000276:immunology*; D051858:Forkhead Transcription Factors / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D008216:Lymphocytic Choriomeningitis / Q000276:immunology* / Q000821:virology*; D008217:Lymphocytic choriomeningitis virus / Q000276:immunology*; D008324:Mammary Tumor Virus, Mouse / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018089:Superantigens / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000166:cytology* / Q000276:immunology*
chemical_list: D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D000949:Histocompatibility Antigens Class II; D018089:Superantigens