The purification and characterization of the EV71 virus.

<p>(A) Purification of EV71 by sucrose density gradient using zonal ultracentrifugation and fractionation analysis by sucrose percentage (Sucrose), contents of total protein (TP) and Vero cell-derived protein (HCP), and EV71-specific units (ELISA). (B) Definition of viral particles distributed in fractions using SDS-PAGE. (C) Electromicrographs of EV71 particles by transmission electron microscopy. (a) Fraction 10 presented a full-particle (F-particle) with infectious capability and a solid particle structure; (b) fraction 13 presented a non-infectious particle (E-particle) with defective particle structure; and (c) pooled viral particles for the vaccine bulk preparation. (D) Quality confirmation of EV71 pooled viral particles before and after formalin inactivation using SDS-PAGE and western blot analysis with a specific monoclonal antibody (Mab979). The molecular weight of VP0, 1, 2, and 3 are as indicated. The black triangle indicates the quantities of loading antigen from high to low.