ABSTRACT
Poliovirus Sabin 1 strain has its own special features that make it a particularly attractive live recombinant mucosal vaccine vehicle. Sabin 1 cDNA was manipulated to have multiple cloning site and viral specific 3C-protease cutting site at the N-terminal end of the polyprotein, named RPS-vax system HIV-1 V3- and principal neutralizing domain (PND)-concatamers were successfully cloned into the multiple cloning site of the vector system and produced expected chimeric viruses by transfection of their RNA transcripts into HeLa cells. These chimeric viruses have shown to express introduced HIV-1 subgenome concatamers efficiently during their replication in the infected HeLa cells. Expressed proteins were confirmed to retain the wild type structures at least in parts. Replication capacity of the chimeric viruses was slightly lower than that of wild type Sabin 1 likely to be due to delay in processing steps during their replication. Differing from the virulent Mahoney vectors, the rec-Sabin 1 chimeric viruses maintained the foreign gene stably during the serial passages. These chimeric viruses have also shown to be able to induce specific humoral immunity to the introduced vaccine proteins when inoculated into the poliovirus receptor-expressing transgenic (Tg-PVR) mice. Antiserum obtained from the immunized transgenic mice showed to have neutralizing capacity to HIV-1 in vitro. These results strongly suggest that the chimeric viruses expressing HIV-1 vaccine epitopes can be used as a good live mucosal vaccine candidate against AIDS.