IMMUNOGENICITY AND PROTECTIVE EFFICACY OF A HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-2 RECOMBINANT CANARYPOX (ALVAC) VACCINE CANDIDATE IN CYNOMOLGUS MONKEYS

The efficacy of a recombinant human immunodeficiency virus (HIV) type 2 canarypox (ALVAC HIV-2) vaccine candidate given alone or in combinat ion with HIV-2 envelope gp125 or HIV-2 V3 synthetic peptides was inves tigated in 14 cynomolgus monkeys, High antibody titers to HIV-2 gp125 were demonstrated in monkeys given booster immunizations with gp125, N eutralizing antibody titers were low (less than or equal to 20) in all monkeys except 2. Significant lymphocyte proliferative responses to k illed HIV-2 virions were observed in monkeys given booster immunizatio ns with gp125, HIV-2-specific cytotoxic T lymphocytes were demonstrate d prior to viral challenge in 3 of 12 monkeys, After challenge with ho mologous cell-free HIV-2 propagated in monkey cells, 4 of 10 monkeys i mmunized with ALVAC HIV-2 plus HIV-2 gp125 or V3 peptides were protect ed, as determined by negative virus isolation and polymerase chain rea ction for viral DNA, Four monkeys immunized with ALVAC HIV-2 alone wer e not protected. All 12 control monkeys became infected, There was no correlation between the immunologic parameters studied and protection against infection in the vaccinated monkeys.