Characterization and assembly of poliovirus-related 45 S particles

Using detergents, 45 S particles could be extracted from poliovirus-infected Vero and human embryonic kidney monolayer cells, but not from HeLa suspension cells. They were composed of the capsid proteins VP0, VP1, and VP3, devoid of RNA, and extremely sensitive to heat or to a slightly alkaline pH. The 45 S particles possessed neutralization epitopes of the N1 and N2 classes, as well as a VP3-linked epitope. The N2 epitopes were lost upon denaturation. In the presence of cell extracts 45 S particles were, like 14 S subunits, assembled to 71 S empty capsids expressing the N1 and N2 epitopes.