Increased beta-chemokine production in peripheral blood mononuclear cells derived from HIV-1-infected individuals by a cationic amphiphilic drug (AY 9944) in vitro

T cell survival/proliferation reconstitution by trifluoperazine in human immunodeficiency virus-1 infection

Recent findings support an indirect relationship between T cell depletion in HIV-1 infection and the rate of virus replication with implications for treatment strategies. We have initiated a new approach to recover immune function through the use of novel chemical agents. A cationic amphiphilic drug that binds to Ca(2+)-calmodulin at high concentrations, [10-[3-(4-methyl-1-piperazinyl)-propyl]-2- (trifluoromethyl)-(10)H-phenothiazine dihydrochloride] [denoted trifluroperazine dihydrochloride (Tfp); molecular weight 480.43] TFP was found at low concentrations (10(-6) to 10(-10) M) to help T cells from AIDS patients to restore proliferation in vitro. Here we show that the Tfp molecule can restore the cell survival of T lymphocytes from PBMCs derived from HIV-1-infected patients in vitro. Tfp enhances T cell proliferation and Th-cell responses by selectively inhibiting cell mortality and apoptosis. The restored antigen-specific response is associated with the synthesis of IL-2 and gamma-interferon. Even though this drug does not possess any detectable antiviral effect, it might be considered as a potential therapeutic agent in HIV-infected patients, to correct immune defects. Besides antiviral compounds, these data may facilitate immune reconstitution in patients with HIV infection and other immunosuppressive diseases.

Induction of G1 cycle arrest in T lymphocytes results in increased extracellular levels of beta-chemokines: a strategy to inhibit R5 HIV-1

The beta-chemokines RANTES (regulated on activation, normal T cell expressed and secreted), macrophage inflammatory protein-1alpha (MIP-1alpha), and MIP-1beta are the natural ligands of the HIV-1 coreceptor CCR5 and compete with the virus for receptor binding. We show that secretion of the beta-chemokines by activated lymphocytes starts before cellular DNA synthesis is detected and demonstrate that transient prolongation of the G(1) phase of the cell cycle by treatment with cytostatic drugs results in increased levels of the three chemokines in culture supernatants. Supernatants collected from peripheral blood mononuclear cells exposed to hydroxyurea, which arrests the cell cycle in late G(1), contained high levels of beta-chemokines. These supernatants were able to inhibit HIV-1 replication when added to cultures of infected lymphocytes. The observed antiviral effect likely was due to the increased levels of beta-chemokines RANTES, MIP-1alpha, and MIP-1beta because (i) supernatants greatly inhibited the replication of HIV-1 BaL, whereas they affected HIV-1 IIIb replication only slightly; (ii) neutralizing antibodies against the chemokines abrogated the antiviral effect of the supernatants; and (iii) the hydroxyurea concentrations shown to up-regulate chemokine levels were not sufficient to inhibit virus replication by depletion of intracellular nucleotide pools. Although antiviral properties have been reported previously for the cytostatic agents shown here to up-regulate beta-chemokine levels, our results provide an additional mechanism by which these drugs may exert antiviral activity. In summary, increased extracellular levels of anti-HIV-1 beta-chemokines resulting from transient prolongation of the G(1) phase of the lymphocyte cell cycle by treatment with cytostatic drugs may help to control the replication of CCR5-using strains of HIV-1.