Structural particularities of parainfluenza type 1 (Sendai) virus progens obtained by cultivation in the presence of ceruloplasmin.

Sendai virus multiplication in the presence of ceruloplasmin resulted in the appearance of qualitatively modified progens. There was an increase in the proportion of incomplete virus particles and a decrease in hemagglutinin and neuraminidase activities, in virus infectivity and antigenicity (with the exception of subviral fractions with predominant hemagglutinating activity). Virus progens obtained in the presence of ceruloplasmin had a higher sensitivity to detergent treatment; virus ghosts formed by re-aggregation of envelope fragments could be observed in the electron microscope.