title: Effects of TH1 and TH2 cytokines on CD8+ cell response against human immunodeficiency virus: implications for long-term survival.
abstract: CD8+ cells from long-term survivors [LTS; infected with human immunodeficiency virus (HIV) for 10 or more years and having CD4+ cell counts of > or = 500 cells per microliters] have a 3-fold greater ability to suppress HIV replication than do CD8+ cells from patients who have progressed to disease (progressors) during the same time period. A change in the pattern of cytokines produced in the host from those that typically favor cell-mediated immunity (T helper 1, TH1 or type 1) to those that down-regulate it (T helper 2, TH2 or type 2) was investigated as a cause of this reduced CD8+ cell anti-HIV function. Treatment of CD8+ cells from LTS with the TH1 cytokine interleukin (IL)-2 enhanced their anti-HIV activity, whereas exposure of these cells to TH2 cytokines IL-4 or IL-10 reduced their ability to suppress HIV replication and to produce IL-2. IL-2 could prevent and reverse the inhibitory effects of IL-4 and IL-10. Moreover, prolonged exposure of CD8+ cells from some progressors to IL-2 improved the ability of these cells to suppress HIV replication. These observations support previous findings suggesting that strong CD8+ cell responses play an important role in maintaining an asymptomatic state in HIV infection. The data suggest that the loss of CD8+ cell suppression of HIV replication associated with disease progression results from a shift in cytokine production within the infected host from a TH1 to a TH2 pattern. Modulation of these cytokines could provide benefit to HIV-infected individuals by improving their CD8+ cell anti-HIV activity.
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D016207:Cytokines / Q000502:physiology*; D018450:Disease Progression; D015658:HIV Infections / Q000276:immunology*; D015497:HIV-1 / Q000254:growth & development / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D016753:Interleukin-10 / Q000502:physiology; D007376:Interleukin-2 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000502:physiology; D018417:Th1 Cells / Q000502:physiology*; D018418:Th2 Cells / Q000502:physiology*; D013997:Time Factors; D014779:Virus Replication
chemical_list: D016207:Cytokines; D007376:Interleukin-2; D016753:Interleukin-10; D015847:Interleukin-4