7th International AIDS Conference Florence, Italy — June 16-21, 1991

Int Conf AIDS 1991 Jun 16-21; 7:101 (abstract no. M.A.1036)
Aggarwal A, Sadoff J, Markham P, Gallo R, Franchini G; PRI/DynCorp, NCI-FCRDC, Frederick, MD, USA

OBJECTIVE: Salmonella-based oral vaccines have shown to be safe, highly immunogenic, and cost effective. Recombinant Salmonella typhimurium (WR4024) expressing HIV-2 antigens could induce viral-specific cytotoxic T lymphocytes (CTLs) in mice.

METHODS: PCR-amplified HIV-2 gag (p17 and p24) and env (amino and carboxy half) gene fragments were cloned into Salmonella. Recombinants were tested for antigen expression by Western blot using HIV-2 human serum. Balb/c mice were inoculated orally with three doses of 10(9) Salmonella recombinants expressing gag and env antigens. Five-eight weeks after the immunization, spleen cells from these mice were stimulated in vitro either with specific peptides or with P815 cells infected with recombinant vaccinia virus expressing HIV-2 env or gag proteins and were processed for CTL by standard methods.

RESULTS: The spleen cells from mice immunized with HIV-2 p17 Salmonella recombinants caused 8-10% lysis of P815 cells, and the CTL epitope was mapped to the previously described peptide (HB30). The spleen cells from mice immunized with recombinant Salmonella-carboxy half env demonstrated 20-25% killing of target cells. Antibodies against HIV-2 in the immunized mice were not detected.

CONCLUSIONS: Preliminary results show that recombinant Salmonella was able to induce CTLs against HIV-2 in mice suggesting that Salmonella could be an efficient, oral, live vaccine candidate for HIV infection.

Copyright © 1991 - International AIDS Society (IAS). Reproduction of this abstract (other than one copy for personal reference) must be cleared through the IAS.