Simultaneous use of contrasting fluorochromes to separate measles and canine distemper viruses in a common system.

Measles and canine distemper viruses were grown together in a Vero monkey kidney cell line. Each virus could be identified and individually titrated by using the color contrast produced by the reddish tetra-methyl rhodamine isothiocyanate-tagged antimeasles conjugate and the green fluorescein isothiocyanate-tagged antidistemper conjugate. Both blue light and green light were used for the excitation of the fluorochromes. Incident light was transmitted to the specimen by a vertical illuminator of the Ploem type.