| abstract |
A cassette vector suitable for use in constructing poliovirus chimaeras, which vector comprises, under the control of a promoter, a full length infectious cDNA of an attenuated strain of type 1 poliovirus having Sal 1 and Dra 1 sites flanking atigenic site 1 of the poliovirus (I), where the numbers represent the numbers of amino acids of the VP1 capsid protein and X represents intervening nucleotides of DNA, present in sufficient numbers to allow the vector to be digested with both Sal 1 and Dra 1, the said Sal 1 and Dra 1 sites being the only Sal 1 and Dra 1 sites in the vector. |