FIG. 3.

Kinetics of decapsidation of purified OSU (top panel) and RRV (bottom panel) virions neutralized by MAbs directed at VP7 and VP4. Purified OSU (10 μl; 200 μg/ml) or RRV (10 μl; 33 μg/ml) virions were mixed with different MAbs (2 μl) and incubated for 1 h at room temperature. The concentration of each MAb in the mixture (in micrograms per milliliter) was as follows: for 1C10, 528; for 5G7, 580; for 159, approximately 500; for M60, approximately 500; for 2G4, 222; and for 7A12, 440. Virus-antibody mixtures (12 μl) were added to a stirred cuvette containing 1.1 ml of EGTA-Ca-EGTA buffers adjusted to the Ca²⁺ concentrations indicated above the panels and were maintained at 25°C. EGTA (10 mM) was added as indicated (arrows) to the OSU virus to reduce the Ca²⁺ concentration from 150 to 50 nM and to the RRV virus to reduce the Ca²⁺ concentration from 26 to 10 nM. MAbs used are indicated. Results of one experiment from a series of three are shown.