Events following the infections of enucleate cells with measles virus.

The development of measles virus (Edmonston) and SSPE measles virus (Horta-Barbosa) has been examined in enucleate BSC 1 cells. New antigen synthesis in measles virus infected enucleate cells has been demonstrated by fluorescent antibody, by the formation of extensive syncytia from enucleate cells alone and by analysis of polypeptide formation by polyacrylamide gel electrophoresis. All polypeptides formed in nucleate cells were also present in enucleate cells but the amount synthesized was reduced to around 20% of that in nucleate cells. There was also a significant reduction in the amount of antigen detected by fluorescent antibody in enucleate as compared to nucleate preparations. Examination of RNA synthesis in infected enucleate cells revealed only a marginal increase in acid-insoluble material. Titration of the output of infectious virus from enucleate cells infected at both 37 and 31 degrees C indicated a consistent reduction of almost two log units compared to nucleate cells. That the enucleate cells were capable of replicating input genome at these times was demonstrated by the successful growth of respiratory syncytial virus, both at 37 and 31 degrees C. SSPE measles virus grew to higher yield in nucleate BSC 1 than measles virus but there was again a reduction of more than two log units in enucleate cells. All polypeptides synthesized in SSPE infected nucleate cells were apparent in enucleate cells.