Immunization with a novel HIV-1-Tat multiple-peptide conjugate induces effective immune response in mice

We report here a novel, highly immunogenic synthetic, multiple-peptide conjugate comprising functional domains Tat(21-40) and Tat(53-68) from HIV-I group M plus Tat(9-20) from HIV-I group O of the HIV-Tat protein (HIV-1-Tat-MPC). Vaccination of mice with HIV-I-Tat-MPC induced an effective immune response to all three functional domains. The anti-HTV-1-Tat-MPC antibodies efficiently inhibited Tar-induced viral activation in monocytes infected with HIV(Ba-L) as well as with various clinical HIV-l isolates, and reduced Tat-mediated cytopathicity in infected cells by 60-75%. Our results indicate that anti-HIV-l-Tat-MPC antibodies inhibit viral pathogenesis, possibly by blocking functional determinants of Tar and disrupting autocrine and paracrine actions of secreted Tat protein. This epitope-specific, synthetic Tat construct may, therefore, provide a subunit AIDS vaccine candidate for inducing an effective immunoprophylaxis response to reduce progression of HIV infection. (C) 2000 Elsevier Science Inc. All rights reserved.