In vitro augmentation of cytotoxicity against tumor cell lines by mumps virus

Cultures of leukocytes from normal subjects and bladder and kidney cancer patients contain cells cytotoxic against various tissue culture human cell lines. Postculture cytotoxicity was increased, in some experiments, after cocultivation with an inactivated strain of mumps virus. Effector cells seem to have an Fc receptor inasmuch as the activity was removed by absorption on immoblized antigen-antibody complexes.