Abstract
The native procapsid (naturally occurring empty capsid) of echovirus type 7 (E7) possesses N-antigenicity, which is as highly strain-specific as the native virion. When the native procapsid is heated, its antigenicity is converted to H-antigenicity which is common among strains of E7 and thus type-specific. However, no difference was detected in the sedimentation rate (80S) and polypeptide composition (VP0, 1 and 3) of the native and heated procapsids.