Selective cytolysis of tumor cells by mumps virus S79.

We studied the sensitivity of several human cancer cell strains (HeLa, HT1080, SPC-A1, and ACHN) and normal cell strains (MRC-5 and Wish) to mumps virus (MuV) S79, a live attenuated vaccine strain. These cells exhibited a differential sensitivity to infection with MuV, and the susceptible sequences were ACHN > HeLa > HT1080 > SPC-A1 > Wish > MRC-5. In experiments in vivo, nude mice with HT1080 fibrosarcoma xenografts were randomly divided into three groups for intratumoral treatment with MuVS79, UV-inactivated MuVS79, and PBS. At 10(7) PFU, live MuVS79 injection caused in 7 of 9 mice complete regression by day 15 while rapid tumor growth occurred in all 9 mice treated with PBS. Rapid tumor progression also occurred in all 8 mice treated with UV-inactivated virus; however, tumor growth was delayed in the logarithmic phase relative to the PBS-treated tumors.