Biological containment space capable of housing HIV- and SIV-infected macaques in European Primate Centres is a key restricting factor in the use of the macaque model for the development of a preventive vaccine against HIV-infection and subsequent progression to the human acquired immunodeficiency syndrome (AIDS). A EU-Concerted Action (CA) "Genetic strategies for an HIV-vaccine evaluated in the macaque model" shall be established to ensure their effective use, and reduce their overall numbers in combination with an improvement of their wellfare.
Within the proposed Concerted Action we intend to explore the use of specific vaccinia vectors, which are apathogenic in humans, as a means of reproducing the protective effect of live-attenuated SIV without the safety problems connected therewith. The vectors are derived from the highly attenuated vaccinia virus strain Modified Vaccinia Ankara (MVA). The partial protection achieved with MVA-vectors expressing only the gag, pol, and env genes of SIV- or HIV-1 strains (what has been demonstrated by Hirsch et al. 1994) can possibly be enhanced by vectors expressing regulatory genes of SIV or HIV or by an immunisation schedule including boosting with alternative replicating vaccine vectors.
Monkeys will be immunised, and their immune system will be monitored before and during the vaccination period. Depending on the outcome of the vaccinations and also on the state of knowledge at that time, a challenge exposure will possibly be performed. For this challenge experiment the construction of new SIV/HIV-chimeric viruses might be necessary and is included as a further aim of the project.