title: The AIDS resistance of naturally SIV-infected sooty mangabeys is independent of cellular immunity to the virus.
abstract: In contrast to human immunodeficiency virus (HIV)-infected humans, natural hosts for simian immunodeficiency virus (SIV) very rarely progress to acquired immunodeficiency syndrome (AIDS). While the mechanisms underlying this disease resistance are still poorly understood, a consistent feature of natural SIV infection is the absence of the generalized immune activation associated with HIV infection. To investigate the immunologic mechanisms underlying the absence of AIDS in SIV-infected sooty mangabeys (SMs), a natural host species, we performed a detailed analysis of the SIV-specific cellular immune responses in 110 SIV-infected SMs. We found that while SIV-specific T-cell responses are detectable in the majority of animals, their magnitude and breadth are, in fact, lower than what has been described in HIV-infected humans, both in terms of cytokine production (ie, IFN-gamma, TNF-alpha, and IL-2) and degranulation (ie, CD107a expression). Of importance, SIV-specific T-cell responses were similarly low when either SIVmac239-derived peptides or autologous SIVsmm peptides were used as stimuli. No correlation was found between SIV-specific T-cell responses and either viral load or CD4+ T-cell count, or between these responses and markers of T-cell activation and proliferation. These findings indicate that the absence of AIDS in naturally SIV-infected sooty mangabeys is independent of a strong cellular immune response to the virus.
authors.affiliation: Emory University, Emory Vaccine Center, Yerkes Primate Research Center, and the School of Public Health, Atlanta, GA, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Dunham
authors.forename: Paola
authors.initials: P
authors.lastname: Pagliardini
authors.forename: Shari
authors.initials: S
authors.lastname: Gordon
authors.forename: Beth
authors.initials: B
authors.lastname: Sumpter
authors.forename: Jessica
authors.initials: J
authors.lastname: Engram
authors.forename: Abeer
authors.initials: A
authors.lastname: Moanna
authors.forename: Mirko
authors.initials: M
authors.lastname: Paiardini
authors.forename: Judith N
authors.initials: JN
authors.lastname: Mandl
authors.forename: Benton
authors.initials: B
authors.lastname: Lawson
authors.forename: Seema
authors.initials: S
authors.lastname: Garg
authors.forename: Harold M
authors.initials: HM
authors.lastname: McClure
authors.forename: Yong-Xian
authors.initials: YX
authors.lastname: Xu
authors.forename: Chris
authors.initials: C
authors.lastname: Ibegbu
authors.forename: Kirk
authors.initials: K
authors.lastname: Easley
authors.forename: Nathalia
authors.initials: N
authors.lastname: Katz
authors.forename: Ivona
authors.initials: I
authors.lastname: Pandrea
authors.forename: Cristian
authors.initials: C
authors.lastname: Apetrei
authors.forename: Donald L
authors.initials: DL
authors.lastname: Sodora
authors.forename: Silvija I
authors.initials: SI
authors.lastname: Staprans
authors.forename: Mark B
authors.initials: MB
authors.lastname: Feinberg
authors.forename: Guido
authors.initials: G
authors.lastname: Silvestri
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology* / Q000821:virology; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology*; D002452:Cell Count; D016665:Cercocebus atys; D018450:Disease Progression; D007113:Immunity, Innate / Q000276:immunology*; D015302:Simian Immunodeficiency Virus / Q000302:isolation & purification*