Heat-Labile Serum Factor Required for Immunofluorescence of Polyoma Tumor Antigens

Abstract

The immunofluorescent demonstration of polyoma tumor antigens in tumor cells requires a heatlabile serum component. With unheated hamster tumor serum, specific fluorescence was observed in polyoma-transformed hamster, mouse, and rat tumor cells. Heated serum usually gave little or no reactivity; the activity of such heated serum could be restored simply by the addition of fresh normal unheated hamster serum.