Abstract
Three enzymeshorseradish peroxidase, alkaline phosphatase, and glucose oxidasewere used as markers in antibody conjugates employed for the detection in the light microscope of either or both T antigens and structural antigens of three viruses: SV40, adenovirus 12 and rat K virus, in infected cell cultures. The specificity of reaction and localization of the antigens was the same with each enzyme and identical with those revealed by fluorochromeconjugates. By using enzymes with reaction products of different colours, two antigens were revealed simultaneously in a single preparation.