Activator of Plasminogen and Protease from Various Cell Cultures and Present in Poliomyelitis Vaccine

Summary

Assays of 25 metabolizing cell culture lines disclosed that 13 of these released an activator of plasminogen resembling tissue activator. Of 4 primary cell lines tested the 3 of kidney origin produced both activator and protease. Assay of a specific cell culture fluid, commercially prepared poliomyelitis vaccine, disclosed the presence of both activator and protease in many lots of vaccine.

Technical assistance of Beatrice L. Burch, Richard J. Low, Alice M. Gochenour is gratefully acknowledged. The authors thank Dr. Hilton B. Levy for his suggestions.