HIV-2 virus variants, namely virus HIV D194 and virus HIV D205, which can be cloned from the corresponding virus isolate HIV D194 (ECACC V 87122303) or from the infected cell line HUT 194 (ECACC V 87122306) or from the virus isolate HIV D205 (ECACC V 87122304), respectively, and their RNA or RNA-fragments and DNA and DNA-fragments derived therefrom and/or proteins and the use thereof for diagnostics and therapy.