Susceptibility of primate‐mouse hybrid cells to SV40

Abstract
Primate‐mouse hybrid cells were challenged with SV40 DNA and monitored for their ability to produce virus. All of the hybrid cells had lost at least half of their primate chromosomes at the time of challenge. Only SV40 T‐antigen‐positive hybrid cells derived from an SV40‐transformed human parental cell produced SV40. This finding suggests that the chromosome(s) necessary for SV40 replication are easily lost on fusion of mouse and primate cells unless the parental cells are already SV40‐transformed.