Multiprotein genetic vaccine in the SIV-Macaca animal model: a promising approach to generate sterilizing immunity to HIV infection

• Published in: Journal of medical primatology 2007-08, Vol.36 (4-5), p.180-194
• Main Authors: Maggiorella, Maria Teresa, Sernicola, Leonardo, Crostarosa, Federica, Belli, Roberto, Pavone-Cossut, Maria Rosaria, Macchia, Iole, Farcomeni, Stefania, Tenner-Racz, Klara, Racz, Paul, Ensoli, Barbara, Titti, Fausto
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Viral - blood; Cell Proliferation; Cynomolgus; Disease Models, Animal; DNA; Female; Flow Cytometry - veterinary; homologous/heterologous prime-boost; Human immunodeficiency virus; IFN-γ/ELISPOT; Immunization - methods; Immunization - veterinary; Lymphocyte Subsets - immunology; Lymphocyte Subsets - virology; Macaca fascicularis; Male; MVA; Neutralization Tests - veterinary; SAIDS Vaccines - immunology; Semliki Forest virus; SFV; Simian Acquired Immunodeficiency Syndrome - immunology; Simian Acquired Immunodeficiency Syndrome - prevention & control; Simian Acquired Immunodeficiency Syndrome - virology; Simian immunodeficiency virus; Simian Immunodeficiency Virus - immunology; SIVmac251; Vaccines, DNA - immunology; Viral Load - veterinary
• ISSN: 0047-2565; 1600-0684
• DOI: 10.1111/j.1600-0684.2007.00236.x

Vaccine combining structural and regulatory proteins is an emerging approach to develop an HIV/AIDS vaccine and therefore, the immunogenicity and efficacy of two regimens of immunization combining structural (Gag/Pol, Env) and regulatory (Rev, Tat, Nef) Simian immunodeficiency virus (SIV) proteins were compared in cynomolgus monkeys. Monkeys were immunized with Modified Vaccine Ankara vector (MVA-J5) (protocol 1) or with DNA, Semliki forest virus and MVA vectors (DNA/SFV/MVA) (protocol 2). At week 32, all monkeys were challenge intravenously (protocol 1) or intrarectally (protocol 2) with 50 MID₅₀ of SIVmac251. Humoral, proliferative responses and in particular in protocol 2, the frequency of IFN-γ producing cells, were measured in all monkeys before and after the challenge. Both vaccine regimens elicited humoral and proliferative responses but failed to induce neutralizing antibodies. Upon intravenous challenge, two out of three MVA-J5 vaccinated monkeys exhibited a long-term control of the viral replication whereas DNA/SFV/MVA vaccine abrogated the virus replication up to undetectable level in three out of four vaccinated monkeys. A major contribution to this vaccine effect appeared to be the IFN-γ/ELISPOT responses to vaccine antigens (Gag, Rev Tat and Nef). These results, indicate that multiprotein heterologous prime-boost vaccination can induce a robust vaccine-induced immunity able to abrogate virus replication.