Analysis by Western blot and immunogold labeling of purified vaccinia virus after controlled degradation of virions. A) Each lane contain the equivalent of 0.06 A260nm units (~0.7 μg) of virus that was incubated in different buffers as described in Materials and Methods and labeled on the top of the figure. The presence of specific proteins in the pellet (P) or supernatant (S) fractions were determined by Western blot and labeled on each lane. B) Vaccinia virus were adsorbed on grids and incubated with Tris (A, D, G), NP-40 (B, E, H), or NP-40+DTT (C, F, I) as described in Materials and Methods. After this treatment, the proteins associated with the virions were identified by immunogold labeling using the antibodies A27 (●) A4 (•) (A, B, C), A10 (●) F17 (•) (D, E, F), A14 (●) H1 (•) (G, H, I) as described in Materials and Methods.