Destruction of human retinoblastoma after treatment by the E variant of encephalomyocarditis virus.

The oncolytic effects of encephalomyocarditis (EMC) virus were examined in human retinoblastoma cell (Y79) cultures which were infected with 10(4 )tissue culture infectious doses (TCIDs) of the E variant of EMC (EMC-E) virus. The TCIDs were used to titer the maximum effect of EMC virus on L-929 cells. In-vitro studies showed 90% cytopathic effect (CPE) at 24 h and 100% CPE at 52 h. The CPE was used to observe pathologic effects of the cells. In-vivo studies employing human retinoblastoma grown as a tumor in nude mice, revealed degeneration of 80% of the tumor cells at 3 days and total destruction at 4 days following inoculation with the EMC-E virus. The virus is highly neurotropic in mice, but is usually not pathogenic in man. These studies suggest a possible new direction in the treatment of retinoblastoma and other malignant tumors using the viral technology.