Immunolabeling of SSPE and wild-type measles viruses in ferret brain cell culture.

Immunocytochemical studies using horseradish peroxidase labeled antibody were undertaken in an attempt to determine whether there are detectable antigenic differences which correlate with the biological properties of differences which correlate with the biological properties of different strains of SSPE and wild-type measles virus grown in ferret bran cell cultures. The rabbit anti-measles hyperimmune serum used in this experiment contained antibodies to all the measles virus proteins when tested by immunoprecipitation. When cells infected with the wild-type measles or productive SSPE virus strains were treated with this serum, heavy deposits of reaction product were seen on the cell membrane and virion envelope. When SSPE serum which contained relativly little antibody to the M protein was applied, a clear unlabeled area was evident just beneath the surface label. Cells infected with the non-productive SSPE strains were labeled by both sera in a spotty or discontinuous pattern on the outer surface of the cell membrane. The differences in membrane labeling seem to reflect differences in the expression of viral membrane proteins by the various SSPE and measles virus strains.