FIG. 3.

Semiquantitative Western blot. Dilutions of purified mature virions or purified IVa2 protein were electrophoresed, blotted, and probed with anti-IVa2 antiserum as described in the text. Lanes: 1, 1.2 × 10¹¹ virus particles; 2, 6.0 × 10¹⁰ particles; 3, 3.0 × 10¹⁰ particles; 4, 200 ng of IVa2; 5, 100 ng of IVa2; 6, 50 ng of IVa2; 7, 25 ng of IVa2; 8, 12.5 ng of IVa2. The band below the IVa2 in lanes 1 to 3 is a truncated product that has been previously reported (30) and was not included in the copy number calculation.