FIG. 2.

Rate zonal sedimentation of intact and disintegrated virions. IPNV stored in TNE (A) and IPNV dialyzed against low-ionic-strength buffer (B) were sedimented by sucrose gradient centrifugation. The RNA was measured as trichloroacetic acid-precipitable, [³H]uridine-labeled material, and viral proteins VP2 and VP3 were identified by MAbs in an ELISA and detected as A₄₁₀. The specificities of the MAbs are shown in an immunoblot (inset in panel A). IPNV-infected RTG-2 cells were run in lanes 1 and 2, and purified IPNV was run in lane 3. Proteins in lane 1 were displayed by a MAb against VP2 (14/2d, also recognizing pVP2), those in lane 2 by a MAb against VP3 (1/2f-3), and the proteins in lane 3 were revealed by an anti-IPNV specific serum. Material of the fraction from the sucrose gradient sedimentation of disintegrated virions containing the highest concentrations of VP3 and RNA was observed by negative staining and EM (C). Bar, 50 nm.