Lack of toxicity and persistence in the mouse associated with administration of candidate DNA- and modified vaccinia virus Ankara (MVA)-based HIV vaccines for Kenya.

Toxicity, biodistribution and persistence of candidate HIV vaccines pTHr.HIVA, a recombinant DNA, and MVA.HIVA, a recombinant modified vaccinia virus Ankara, were determined in the Balb/c mouse. The mice were injected with either two doses of intramuscular pTHr.HIVA DNA (50 microg each, separated by an interval of 14 days), two doses of intradermal MVA.HIVA (10(6) plaque-forming units each, separated by an interval of 14 days), or a combination of the two vaccines, each given in two doses, in a prime-boost regimen. The study showed no significant toxic effects, either local or systemic, under any of these employed dosing regimens. With the exception of the sites of delivery, the vaccine-derived HIVA DNA sequences were undetectable 5 weeks after the last dosing. Thus, both the vaccines alone and in a combination were considered safe and suitable for the use in phase I trials in humans.