Virus-like bodies in a transplantable mouse plasma cell tumour

THE plasma cell tumour designated X5563 originated in a 22½-month-old female C3H/He mouse in the Cancer Research Genetics Laboratory, Berkeley, California. It was successfully transplanted by Dr. H. I. Pilgrim, and mice bearing the second transplant generation were sent to the National Cancer Institute, Bethesda, Maryland, where it was routinely transplanted every 60 days in C3H/He mice for several transplant generations1,2. Mice inoculated with the tumour were sent to us by Dr. M. Potter, of the National Cancer Institute. The tumour is now in its third transplant generation in our hands.