The AIDS resistance of naturally SIV-infected sooty mangabeys is independent of cellular immunity to the virus.
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.
Dunham
Richard
R
Emory University, Emory Vaccine Center, Yerkes Primate Research Center, and the School of Public Health, Atlanta, GA, USA.
Pagliardini
Paola
P
Gordon
Shari
S
Sumpter
Beth
B
Engram
Jessica
J
Moanna
Abeer
A
Paiardini
Mirko
M
Mandl
Judith N
JN
Lawson
Benton
B
Garg
Seema
S
McClure
Harold M
HM
Xu
Yong-Xian
YX
Ibegbu
Chris
C
Easley
Kirk
K
Katz
Nathalia
N
Pandrea
Ivona
I
Apetrei
Cristian
C
Sodora
Donald L
DL
Staprans
Silvija I
SI
Feinberg
Mark B
MB
Silvestri
Guido
G
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*