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RESEARCH PRODUCT

The 2-5A System and HIV Infection

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The human immunodeficiency virus type 1 (HIV-1) is the etiologic agent of acquired immunodeficiency syndrome (AIDS). The progression of this retro viral disease is associated with various clinical manifestations, including the acquisition of an immunodeficient state, the frequent presence of neurological disorders, and some malignancies (reviewed in Barre-Sinoussi et al. 1983; Wong-Staal and Gallo 1985; Fauci 1988). Immunologic dysfunctions caused by HIV-1 infection include disorders in the production of cytokines (Murray et al. 1984; Abb et al. 1986). For example, a significant decrease in the production of interferon-α (IFN-α) by cultured peripheral blood mononuclear cells (PBMC) from patients infected with HIV-1 has been reported (Rossol et al. 1989; Voth et al. 1990). In addition, the production of IFN-γ is decreased in patients at late CDC stage III and CDC IV (Rossol et al. 1989). However, at late stages of the disease, the IFN-γ levels and, in particular, IFN-a levels increase (Buimovici-Klein et al. 1986; Skidmore and Mawson 1987; Rossol et al. 1989). Recent results suggest that HIV is capable of inducing in vitro production of conventional acid-stabile IFN-a, while only low levels of acid-labile IFN-α are present in sera of patients with AIDS-related complex (ARC) and AIDS (Capobianchi et al. 1988). There are also some hints that one enzyme of the 2′,5′-oligoadenylate (2-5A) pathway, the ribonuclease L (RNase L), is inactive in blood lymphocytes of AIDS patients (Carter et al. 1987), despite a high level of its activator 2-5A, indicating the presence of an inhibitor in HIV-infected cells which interferes with the proper functioning of this antiviral pathway. Therefore restoration of the natural 2-5A synthetase (2-5OAS)/RNase L and dsRNA-dependent protein kinase pathways may help to overcome the depressed immune status of ARC and AIDS patients.