FIG. 4.

Neutralization of authentic and clonally derived PaV. BSR-T7/5 cells were transfected with 2.5 μg of PaV1(1,0) + PaV2(0,0) and incubated at 28°C for 48 h before the cells were washed and lysed by freezing and thawing. These lysates (lanes 5 to 8) and purified wild-type PaV particles (lanes 1 to 4) were incubated with RNase A (lanes 2 and 6), PaV antiserum (lanes 3 and 7), or both RNase A and PaV antiserum (lanes 4 and 8), or mock-treated with PBSM (lanes 1 and 5). The treated samples were used to infect FB33 cells. After 22 h of incubation at 28°C, actinomycin D was added at 20 μg/ml, and 30 min later replicating RNAs were metabolically labeled by incorporation of [³H]uridine (20 μCi/ml) for a period of 2 h before total cellular RNAs were harvested. RNAs were resolved by electrophoresis on a 1% agarose-formaldehyde gel and visualized by fluorography. PaV RNA1 and RNA2 are indicated on the left.