FIG 1.

Characterization of the serum antibody response to recombinant anthrax protective antigen (rPA) vaccination. (A) ELISpot was used to determine the number of PA-specific and total IgG⁺ ASCs per million PBMCs at day 28 and day 35 postvaccination. Error bars indicate the standard deviations of duplicates. (B) The ability of the donor serum, collected at day 0, day 28, and day 35, to protect J774A.1 cells from LeTx-mediated cell death was assessed using the MTT assay. Data are means ± SDs from at least three independent experiments, each conducted in duplicate.