FIG. 4.

DNA vaccination with plasmid expressing SEOV or HTNV G1 and G2 elicits high-titer neutralizing antibody responses in rhesus monkeys. Rhesus monkeys were vaccinated with either pWRG/SEO-M(x), pWRG/HTN-M(x), negative control DNA, or rVV/HTN-M+S by the indicated route as described in Materials and Methods. Serum samples were obtained before vaccination (column P) and then 3 weeks after the first (column 1), second (column 2), and third (column 3) vaccinations. The PRNT titer represents the reciprocal serum dilution that reduced virus plaque number by 80% or 50%. The live virus vaccinia recombinant vaccine (rVV/HTN-M+S) was administered only two times at a 6- week interval. The identification code for each monkey is shown below its respective plot.