title: Nonpathogenic SIV infection of sooty mangabeys is characterized by limited bystander immunopathology despite chronic high-level viremia.
abstract: HIV-infected humans and SIV-infected rhesus macaques who remain healthy despite long-term infection exhibit exceptionally low levels of virus replication and active antiviral cellular immune responses. In contrast, sooty mangabey monkeys that represent natural hosts for SIV infection do not develop AIDS despite high levels of virus replication and limited antiviral CD8(+) T cell responses. We report here that SIV-infected mangabeys maintain preserved T lymphocyte populations and regenerative capacity and manifest far lower levels of aberrant immune activation and apoptosis than are seen in pathogenic SIV and HIV infections. These data suggest that direct consequences of virus replication alone cannot account for progressive CD4(+) T cell depletion leading to AIDS. Rather, attenuated immune activation enables SIV-infected mangabeys to avoid the bystander damage seen in pathogenic infections and protects them from developing AIDS.
authors.affiliation: Departments of Medicine and Microbiology and Immunology and, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Guido
authors.initials: G
authors.lastname: Silvestri
authors.forename: Donald L
authors.initials: DL
authors.lastname: Sodora
authors.forename: Richard A
authors.initials: RA
authors.lastname: Koup
authors.forename: Mirko
authors.initials: M
authors.lastname: Paiardini
authors.forename: Shawn P
authors.initials: SP
authors.lastname: O'Neil
authors.forename: Harold M
authors.initials: HM
authors.lastname: McClure
authors.forename: Silvija I
authors.initials: SI
authors.lastname: Staprans
authors.forename: Mark B
authors.initials: MB
authors.lastname: Feinberg
mesh_terms: D000818:Animals; D017209:Apoptosis; D001853:Bone Marrow / Q000473:pathology; D018791:CD4 Lymphocyte Count; D016665:Cercocebus atys; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D016097:Simian Acquired Immunodeficiency Syndrome / Q000209:etiology* / Q000276:immunology / Q000473:pathology / Q000821:virology; D015302:Simian Immunodeficiency Virus / Q000276:immunology* / Q000472:pathogenicity*; D016176:T-Lymphocyte Subsets / Q000276:immunology; D013997:Time Factors; D014766:Viremia / Q000209:etiology / Q000276:immunology / Q000473:pathology / Q000821:virology; D014774:Virulence