IFN‐γ Restores HIV‐ and Non‐HIV‐Specific Cell Mediated Immune Response In Vitro and Its Activity is Neutralized by Antibodies from Patients with AIDS

The addition of IFN‐γ to cultures of peripheral blood mononuclear cells (PBMCs) obtained from asymptomatic HIV‐infected patients increased cell proliferation in response to HIV envelope synthetic peptides (Env), influenza A virus (VIRUS), andallogeneic lymphocytes (ALLO) but not to phytohaemagglutinin (PHA) stimulation. F(Ab)2 fragments of IgG purified from the sera of HIV‐seropositive patients specifically interfered with IFN‐γ‐induced cell proliferation in response to recallantigens. Neutralization of the lymphokine activity was found to be sustained by specific IFN‐γ antibodies. Data obtained demonstrate that IFN‐γ can restore the cell‐mediated immunity of a number of asymptomatic HIV+ individuals invitro, while IFN‐γ antibodies present in sera of patients with AIDS interfere with the activity of the lymphokine.