Life cycle of the herpes simplex disabled infectious single-cycle (DISC) vector. The HSV-DISC vector lacks the glycoprotein-H gene, an essential component for the infectivity of HSV. The vector particles are made in a complementary cell (CR1 or CR2), which supplies the gH gene product in trans. The vector generated may have any gene of interest substituted for the missing gH gene. On entry into a permissive cell, herpes virus and inserted gene products are made, but only noninfectious (gH negative) virus is made. In a nonpermissive cell, an abortive infection may result, with limited expression of herpes genes.