FIG. 6.
RT activity in FIV-infected trCrFK cells. trCrFK cells were infected with Petaluma (a), V1CSF (b), or FIV-Ch (c) at 104.5 TCID50/ml or with FIV-ChTM (d), FIV-ChSU (e), or FIV-ChV35 (f) at 102.5 TCID50/ml, and RT activity was measured in culture supernatants at days 0, 3, and 7 p.i. trCrFK cell lines included nontransfected parent cells and cells transfected with human CCR3, CXCR4, or CCR5. RT activity is expressed as counts per minute per milliliter of medium, with the mean ± standard error of the mean from triplicate samples shown. Significant differences relative to parent cells were determined by ANOVA and the Tukey-Kramer posthoc test (∗, P < 0.01; ∗∗, P < 0.005). Increased RT activity was detected over the time course in all Petaluma- and FIV-ChTM-infected cell lines, but following infection with the other viruses, increased RT activity was detected only in cells transfected with CCR3 or CCR5.