Figure 1.

Optimization of the FIX expression cassette. (a) The two identical plasmid expression cassettes, differing only in the indicated FIX cDNAs (LP1 promoter-driven codon-optimized and human liver codon-optimized with the Padua mutation), were transfected into human hepatoma cells, HepG2, and FIX activity was determined by one-stage clot assay 24 h post-transfections. (b) Twenty micrograms of the indicated plasmid DNA was hydrodynamically injected separately into FIX wild-type mice, and total FIX antigen levels were detected in sera by ELISA 24 h postinjections. (c) FIX activity in sera from hydrodynamically injected wild-type FIX mice was detected by ELISA 24 h postinjections. ELISA, enzyme-linked immunosorbent assay; FIX, factor IX; HepG2, hepatocellular carcinoma.