Safety and Immunogenicity Study of Recombinant Modified Vaccinia Virus Ankara (MVA) Virus to Treat HIV Infection

At the end of 2004 there were more than 40 million people infected worldwide with HIV, with an estimated 16,000 new infections every day (Joint United Nations Programme on HIV/AIDS \[UNAIDS\], 2004). The HIV epidemic threatens whole societies particularly in Africa and Asia and rates of infections in the Western countries have also increased over the last few years. However, despite more than 15 years of research, an effective vaccine against HIV and acquired immunodeficiency syndrome (AIDS) has still not been developed. There is considerable evidence that cellular immune responses can effectively control HIV-1 replication during acute and chronic infections thereby possibly protecting individuals from infection and preventing the spread of HIV. To be truly effective in the general population, a vaccine must induce responses specific to immunologically conserved regions. The epitope-based vaccine MVA-mBN32 represents a very logical approach to this problem because of its potential to elicit a polyfunctional immune response and to focus these responses to conserved epitopes. In this study the safety, tolerability, and immunogenicity of a recombinant MVA-BN® vaccine expressing cytotoxic T lymphocyte (CTL) and helper T lymphocyte (HTL) epitopes of HIV-1 (MVA-mBN32) in 36 healthy volunteers will be examined. This will include a full analysis of CD4+ T helper cells and CD8+ CTL responses to these epitopes, to establish the potential of such a homologous prime-boost vaccine approach to induce a broad cell-mediated response to different HIV antigens.