A cassette vector for the construction of antigen chimaeras of poliovirus

A cassette vector has been constructed which allows the rapid and extensive modification of one of the neutralizing antigenic sites of the Sabin 1 poliovirus vaccine strain, P1/LSc 2ab. Unique restriction endonuclease sites flanking antigenic site 1 have been engineered into a full-length infectious Sabin 1 cDNA clone with minimal alteration to the coding sequence. This facilitates replacement of this region by oligonucleotides encoding foreign amino acid sequences. Our results indicate that this region is highly flexible in terms of the number and sequence of amino acids which can be accommodated.