title: Loss of naïve cells accompanies memory CD4+ T-cell depletion during long-term progression to AIDS in Simian immunodeficiency virus-infected macaques.
abstract: Human immunodeficiency virus and simian immunodeficiency virus (SIV) induce a slow progressive disease, characterized by the massive loss of memory CD4+ T cells during the acute infection followed by a recovery phase in which virus replication is partially controlled. However, because the initial injury is so severe and virus production persists, the immune system eventually collapses and a symptomatic fatal disease invariably occurs. We have assessed CD4+ T-cell dynamics and disease progression in 12 SIV-infected rhesus monkeys for nearly 2 years. Three macaques exhibiting a rapid progressor phenotype experienced rapid and irreversible loss of memory, but not naïve, CD4+ T lymphocytes from peripheral blood and secondary lymphoid tissues and died within the first 6 months of virus inoculation. In contrast, SIV-infected conventional progressor animals sustained marked but incomplete depletions of memory CD4+ T cells and continuous activation/proliferation of this T-lymphocyte subset. This was associated with a profound loss of naïve CD4+ T cells from peripheral blood and secondary lymphoid tissues, which declined at rates that correlated with disease progression. These data suggest that the persistent loss of memory CD4(+)T cells, which are being eliminated by direct virus killing and activation-induced cell death, requires the continuous differentiation of naïve into memory CD4+ T cells. This unrelenting replenishment process eventually leads to the exhaustion of the naïve CD4+T-cell pool and the development of disease.
authors.affiliation: Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nishimura
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Igarashi
authors.forename: Alicia
authors.initials: A
authors.lastname: Buckler-White
authors.forename: Charles
authors.initials: C
authors.lastname: Buckler
authors.forename: Hiromi
authors.initials: H
authors.lastname: Imamichi
authors.forename: Robert M
authors.initials: RM
authors.lastname: Goeken
authors.forename: Wendy R
authors.initials: WR
authors.lastname: Lee
authors.forename: Bernard A P
authors.initials: BA
authors.lastname: Lafont
authors.forename: Russ
authors.initials: R
authors.lastname: Byrum
authors.forename: H Clifford
authors.initials: HC
authors.lastname: Lane
authors.forename: Vanessa M
authors.initials: VM
authors.lastname: Hirsch
authors.forename: Malcolm A
authors.initials: MA
authors.lastname: Martin
mesh_terms: D000208:Acute Disease; D000818:Animals; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002908:Chronic Disease; D018450:Disease Progression; D006801:Humans; D007156:Immunologic Memory; D008253:Macaca mulatta; D012367:RNA, Viral / Q000097:blood; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology* / Q000503:physiopathology* / Q000821:virology; D015302:Simian Immunodeficiency Virus / Q000276:immunology / Q000472:pathogenicity*
chemical_list: D012367:RNA, Viral