FIG. 4.

Detection of PVA VPg in virions by IEM. The complexes of anti-VPg antibodies and virion-associated VPg were visualized with gold-conjugated protein A. The size of the gold particles is 15 nm. (A) The complexes of gold-conjugated protein A and anti-VPg antibodies are detected at only one end of the virion (bar, 200 nm). (B) Magnified view of a labeled PVA particle. (C) Preimmune IgGs or gold-conjugated protein A does not bind directly to the virions (particles not treated with anti-VPg antibodies; bar, 500 nm). (D) Virus-like particles, which contain neither viral RNA nor VPg, are not recognized by anti-VPg antibodies (bar, 500 nm).