FIG 4.

Administration of rXlIFN to tadpoles prior to FV3 infection reduces viral burdens and viral DNA Pol II expression. Stage 54 tadpoles (n = 6 per treatment group) were injected i.p. with 500 ng of rXlIFN or an equal volume of the vector control. After 8 h, tadpoles were injected i.p. with 10⁴ PFU FV3 in APBS or APBS alone. At 6 dpi, peritoneal leukocytes and kidneys were removed for RNA and DNA isolation. Peritoneal leukocytes were isolated from 3 individual tadpoles and pooled to obtain sufficient RNA and DNA for analysis, and 3 distinct pools were examined. The vDNA Pol II copy number in the derived cDNA and DNA samples was measured by absolute qRT-PCR (using a vDNA Pol II standard curve) to determine FV3 gene expression and viral loads in kidneys (A and B) and PLs (C and D). Results are means ± SEMs. *, significant difference from vector-treated controls (P < 0.05).