Plasmid maps and expression determinations for the bicistronic lymphotactin (LTN) DNA vaccines. (A) Circular plasmid maps for LTN/V (pBud-LTN/V) and LTN/F1-V (pBud-LTN/F1-V) DNA vaccines. Pcmv, cytomegalovirus promoter; ori, origin of replication; BGH PA, bovine growth hormone polyadenylation signal; PEF-1α, elongation factor 1α promoter; Zeo-R, zeomycin resistance; SV40 PA, simian virus 40 polyadenylation signal. (B) Expression of LTN was determined by LTN-specific ELISA using supernatants from 293A cells transfected with the pBud-LTN/V or -LTN/F1-V DNA vaccines. Data represent the mean ± SEM of two experiments analyzed using the Mann-Whitney U-test: *, P < 0.05. (C) To detect V-Ag and F1-V fusion Ag expression by the pBud -LTN/V or -LTN/F1-V DNA vaccines, cell lysates from transfected 293A were subjected to Western immunoblot analysis using rabbit anti-V-Ag serum.