FIG. 3.

Measurement of plasma virus load (copies of viral RNA/ml plasma). Plasma viremia after challenge was assessed by a real-time RT-PCR assay for FIV gag RNA and is measured in FIV RNA copies per ml of plasma. Plasma samples harvested from cats vaccinated with FIV-pPPRΔvif (A), FIVΔvifATGγ (B), or FIV-pPPRΔvif and pCDNA-IFNγ (C) and from unvaccinated control cats (D) were tested at 2, 5, 8, and 12 weeks postchallenge. The limit of detection of this real-time RT-PCR assay for FIV RNA is 50 copies per ml. Cat identification numbers are shown on the right.