Abstract: Recombinant vectors which are based on the Modified Ankara Virus (MVA) as preventive and therapeutic vaccines against AIDS The recombinant viruses contain sequences which are inserted at an MVA insertion site and enable simultaneous expression of antigens  a HIV-1 Env protein consisting of a gp120 protein lacking sequences corresponding to protein gp 41 and a chimeric fusion protein of Gag  Pol and Nef