Expression of retroviral vectors hFX-514 or hAAT-540B and production of anti-hFX antibodies in vivo in rats. (A) hFX and hAAT levels in hFX-514–transduced rats. Rats were treated with a 70% partial hepatectomy. Twenty-four hours later, 4 mL containing ∼12 × 106 cfu of hFX-514 was injected into the portal vein. Plasma was analyzed for hFX (solid symbols) and hAAT (open symbols) by ELISA. (B) hFX and hAAT levels in hAAT-540B–transduced rats . Rats were transduced with ∼2 × 106 cfu of hAAT-540B. Plasma was analyzed for hFX (solid symbols) and hAAT (open symbols). (C) Titers of anti-hFX antibodies in hFX-514–transduced rats. Plasma was initially analyzed for anti-hFX antibodies at a 1:100 dilution as described in the Materials and Methods. If the result was negative, these samples were reported as having a titer of 1:50 or less. Samples that were positive at 1:100 were diluted serially and are reported as the highest dilution at which the OD in the assay was at least twice as high as the OD observed in the same assay using a 1:100 dilution of the pretreatment plasma for that rat. Rats no. 115 and 119 had no detectable anti-hFX antibodies. Rats no. 113 and 114 had anti-hFX antibody titers of 1:100 to 1:400 at 3 weeks or later after transduction. (D) Titers of anti-hFX antibodies in hAAT-540B–transduced rats. Plasma from 540B-transduced rats was analyzed for anti-hFX antibodies as described in (C). Both rats were occasionally weakly positive in this assay.
