Abstract: A recombinant neurotropic HSV-1 vector carrying the gene for human HPRT under the direction of the viral TK promoter expresses a high level of human enzyme in host neuronal cells, yet has reduced cytopathicity. The virulence of the HSV-1 vector is further reduced by rendering it replication-defective through UV-irradiation or the use of a replication-defective HSV-1 deletion mutant in its construction. The recombinant vector is also provided with a non-viral site of initiation of DNA synthesis, which permits the HPRT gene to replicate independently of the viral genome, thus providing means for amplification of the gene in the host. The recombinant HSV-1 vector's high level of expression of HPRT coupled with decreased virulence allows treatment of HPRT deficieny by direct infection of the host organism.

Abstract: A recombinant neurotropic HSV-1 vector carrying the gene for human HPRT under the direction of the viral TK promoter expresses a high level of human enzyme in host neuronal cells, yet has reduced cytopathicity. The virulence of the HSV-1 vector is further reduced by rendering it replication-defective through UV-irradiation or the use of a replication-defective HSV-1 deletion mutant in its construction. The recombinant vector is also provided with a non-vital site of initiation of DNA synthesis, which permits the HPRT gene to replicate independently of the viral genome, thus providing means for amplification of the gene in the host. The recombinant HSV-1 vector's high level of expression of HPRT coupled with decreased virulence allows treatment of HPRT deficieny by direct infection of the host organism.