Repair of the in vitro HIV-1-induced immunosuppression and blockade of the generation of functional suppressive CD8 cells by anti-alpha interferon and anti-Tat antibodies

The acute human immunodeficiency virus type 1 (HIV-1) infection of activated peripheral blood mononuclear cells (PBMCs) from normal donors results in inhibition of cell proliferation and generation of functional suppressive T cells. Cultured HIV-1 infected PBMCs but not uninfected PBMCs, following irradiation, can inhibit the proliferation of antigen-activated autologous T cells in a dose-dependent way. CD8' cell subpopulation is responsible for this inhibition. The presence of anti-alpha interferon (IFNα) and anti-Tat antibodies in the culture medium counteracts the HIV-1-induced immunosuppression and prevents the generation of suppressive T cells by these PBMCs. The reported data should have major implications for strategies of AIDS treatment which, in association with antiviral drugs, aim at targetting immune disorders.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Even transcriptionally competent proviruses are silent in bovine leukemia virus induced tumor cells.

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Biological effect of active anti-IFNα immunization in HIV-infected patients

Circulating interferon (IFN) was investigated in HIV-1 seropositive patients by measuring the IFNα antiviral effect in the serum. While serum of healthy seronegative individuals exhibits an antiviral effect, not due to IFNs, considered as background, serum of seropositive patients showed an additional antiviral effect due to the abnormal presence of IFNα. Increased titers of IFNα were found in the course of the HIV infection and seemed to correlate with the evolution of AIDS disease. Furthermore, patients immunized against IFNα had both stabilized CD4 cell count and decreased IFNα in their serum. HIV-1-infected patients also exhibited higher titers of natural anti-IFN antibodies than seronegative controls and the level of specific antibodies (Abs) markedly increased in immunized patients. Finally, serum from immunized patients, when compared to seronegative controls, exhibits an interferon neutralizing capacity.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A group specific anamnestic immune reaction against HIV-1 induced by a candidate vaccine against AIDS

The first experimental immunization of humans against the AIDS retrovirus, HIV-1, was started in a series of HIV seronegative, healthy volunteers in November 19861. For the primary vaccination recombinant vaccinia virus (V25)2 expressing the complete gp160 env protein3 of the HTLV-IIIB strain4,5 of HIV-1 was introduced by scarification. This elicited a weak primary response which we subseqently attempted to enhance by additional immunizations (boosting), using four different immunization protocols. We report here that intravenous injection of paraformaldehyde-fixed autologous cells infected in vitro with V25 (individual D.Z.) gave the best results. This individual received second and third boosts of intramuscular gp160 derived from an HTLV-IIIB clone using the hybrid vaccinia virus/bacteriophage T7 expression system6. An anamnestic humoral and cellular immune reaction was achieved for over one year after the original vaccination, with high levels of antibodies to the viral envelope, and neutralizing antibodies against divergent HIV-1 strains such as HTLV-III B4,5,7 and HTLV-IIIRF (also called HTLV-III HAT)3,5 after the first boost. In addition, group-specific cell-mediated immunity and cell-mediated cytotoxicity against infected T4 cells were obtained after the primary vaccine and enhanced by the boosts. Finally, skin tests showed both immediate and delayed hypersensitivity to gp160 in vivo. Although this protocol is not practical for a large scale vaccine trial, our results show for the first time that an immune state against HIV can be obtained in man. © 1988 Nature Publishing Group.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A randomized, placebo-controlled, blind anti-AIDS clinical trial: Safety and immunogenicity of a specific anti-IFNα immunization

HIV-induced cytokine dysregulation, incluCling overproduction of the antiproliferative and cytolytic IFNα cytokine, represents a major component of the immune disorders characterizing AIDS. To block the overproduction of IFNα we designed an AIDS vaccine combination which included both an anti-HIV and/or an anti-IFNα immunization. The safety and immunogenicity of this multicomponent vaccine were tested in mice, Cercopithecus, two HIV noninfected individuals, and six HIV-1 seropositive immunocompromised patients enrolled in a 1-year open clinical trial. We now report the result of a 9-month short-term randomized, blind, placebo-controlled clinical trial (Phase I/II) performed in HIV-1 patients (22 individuals) to confirm safety/tolerance of the anti-IFNα vaccine and its immunogenicity and to evaluate whether the complex vaccine initially used could be simplified by removal of HIV compo-nent(s). Three groups of patients received inactivated IFNα (i-IFNα) associated with the immunomodulator P40 with HIV-1 antigens (groups B and C) or without (group A), and one group (D) was placebo. The clinical follow-up documented among those receiving i-IFNα showed that none developed AIDS and/or required antiretroviral chemotherapy. Viral load did not increase and CD4 cell count as well as cell-mediated immunity (CMI) stabilized or even significantly increased in group A. Immunogenicity of the preparations was determined by a positive delayed-type hypersensitivity (DTH) reaction to i-IFNα and the presence of serum antibodies to i-IFNα and to HIV-1 peptides, occurring only in treated patients. As previously planned, based on these safety data, the trial has been extended for an additional year and all patients were switched to protocol A (i-IFNα + P40). This second period of the trial, now open and ongoing, should allow us to evaluate further the innocuity of the i-IFNα preparation and whether anti-IFNα vaccine could provide a long-lasting CD4 cell count as well as CMI stabilization. © 1994 Raven Press Ltd. New York.SCOPUS: ar.jinfo:eu-repo/semantics/publishe