Abstract
The relationship of RSV(O) to other avian tumour viruses was studied by virus interference and serological cross neutralization. Viruses of subgroup B interfere with RSV(O) on chicken cells but not on quail cells. Viruses of sub-groups A and C enhance the focus forming efficiency of RSV(O). Antisera to RSV(O) and avian tumour viruses of sub-group A, B and C do not cross-react, but serological cross-reaction was found between RSV(O) and sub-group D.
The ability of RSV(O) and L-R cells to stimulate anti-viral antibodies has been investigated.
No helper virus in RSV(O) stocks was demonstrable by interference assays.