Replication of Mouse Sarcoma Virus (Moloney) and its helper in a human heteroploid cell line of malignant origin

A human heteroploid cell line of malignant origin (J111) was infected with Mouse Moloney Sarcoma Virus. [MSV-M(MLV)]. The replication of the virus was demonstrated by different methods. After a few passages of infected cultures, the transforming component of MSV-M(MLV) disappeared from the supernatant fluids and cells. The non transforming helper component continued to be produced. The relatively low amount of helper virus released by the cells suggests a control of its replication in the J111 cellular system.