Superinfection of HVJ Carrier HeLa Cells with Ultraviolet‐Irradiated Newcastle Disease Virus

Abstract

The mechanism of enhancement of growth of partially ultraviolet (UV)‐inactivated Newcastle disease virus (NDV) in HeLa cells persistently infected with hemagglutinating virus of Japan (HVJ) (HeLaHvJ) was investigated. HeLaHVJ cells and normal HeLa cells were inoculated with UV‐irracliated NDV under similar experimental conditions, and numbers of both infective centers and NDV‐antigen producing cells in each culture were counted. It was found that the percentage of HeLaHVJ cells which produced infectious NDV or NDV‐antigen during the first cycle of infection was approximately 1.5 times higher than that of normal HeLa cells. Survival curves of UV‐irradiated NDV showed that NDV appeared more resistant to UV when titrated in HeLaHVJ cells than in assay in normal HeLa cells. Possible explanations for this phenomenon were discussed © jointly owned by author and Igakushoin (Publisher)