Cellular Immune Responses in Asymptomatic Human Immunodeficiency Virus Type 1 (HIV-1) Infection and Effects of Vaccination with Recombinant Envelope Glycoprotein ofHIV-1

Abstract

Effects of human immunodeficiency virus type 1 (HIV-1) recombinant envelope glycoprotein vaccines on cell-mediated immune (CMI) responses were assessed in HIV-1-infected patients. Asymptomatic, antiretroviral-treatment-naïve, HIV-1-infected patients with CD4(+) T-cell counts greater than 400/microl received multiple intramuscular injections of HIV-1 IIIB recombinant envelope glycoprotein (rgp160) vaccine or HIV-1 MN recombinant envelope glycoprotein (rgp120) vaccine (eight patients, referred to as the HIV-1 vaccinees) or placebo or hepatitis B vaccine (three patients, referred to as the controls). Lymphocyte proliferation in response to HIV-1 envelope glycoproteins, both homologous and heterologous to the HIV-1 immunogens, was absent prior to study treatment in all patients but increased significantly during the vaccination series and after the final vaccination in HIV-1 vaccinees (P < 0.05) and remained absent in control patients. In flow cytometric analyses of intracellular cytokines, T-cell receptor stimulation with an anti-CD3 antibody induced gamma interferon (IFN-gamma) expression by activated CD4(+) and CD8(+) lymphocytes at greater frequencies than did stimulation with recombinant envelope glycoprotein and p24 of HIV-1 (P < 0.05). Mean frequencies of HIV-1 envelope glycoprotein-stimulated, activated intra-cellular IFN-gamma-producing CD4(+) and CD8(+) lymphocytes and of interleukin-2-producing CD4(+) lymphocytes did not increase after vaccination, but cytokine-producing cells were detectable in some patients. Comparing pre- to post-HIV-1 vaccination time points, changes in frequencies of activated, IFN-gamma-producing CD4(+) cells correlated inversely with changes in lymphocyte proliferation in response to recombinant envelope glycoprotein in HIV-1 vaccinees (P < 0.05). Increased CMI responses to HIV-1 envelope glycoprotein measured by lymphocyte proliferation were associated with HIV-1 recombinant envelope glycoprotein vaccines.