Pathogenesis of HIV infection: what the virus spares is as important as what it destroys.
Upon transmission to a new host, HIV targets CCR5+ CD4+ effector memory T cells, resulting in acute, massive depletion of these cells from mucosal effector sites. This depletion does not initially compromise the regenerative capacity of the immune system because naive and most central memory T cells are spared. Here, we discuss evidence suggesting that frequent activation of these spared cells during the chronic phase of HIV infection supplies mucosal tissues with short-lived CCR5+ CD4+ effector cells that prevent life-threatening infections. This immune activation also facilitates continued viral replication, but infection and killing of target T cells by HIV are selective and the impact on effector-cell lifespan is limited. We propose, however, that persistent activation progressively disrupts the functional organization of the immune system, reducing its regenerative capacity and facilitating viral evolution that leads to loss of the exquisite target cell-sparing selectivity of viral replication, ultimately resulting in AIDS.
Grossman
Zvi
Z
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. grossman@helix.nih.gov
Meier-Schellersheim
Martin
M
Paul
William E
WE
Picker
Louis J
LJ
D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000821:virology; D000208:Acute Disease; D000818:Animals; D000941:Antigens / Q000276:immunology; D002908:Chronic Disease; D018450:Disease Progression; D015658:HIV Infections / Q000276:immunology* / Q000503:physiopathology* / Q000821:virology; D015497:HIV-1 / Q000276:immunology / Q000472:pathogenicity* / Q000502:physiology*; D006801:Humans; D018928:Immunity, Mucosal / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D018655:Lymphocyte Count; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000821:virology; D014779:Virus Replication
D000941:Antigens