Abstract
Using the technique of immune precipitation of [35S]methionine-labelled infected cell polypeptides followed by SDS-polyacrylamide gel electrophoresis and autoradiography it has been shown that SV5 and a closely related isolate are both antigenically related to human parainfluenza virus type 2. Limited cross-reactions were also demonstrated between parainfluenza virus types 1 and 3 by this method and the apparent molecular weights of the major structural components of human parainfluenza virus types 2 and 3 have been deduced.