Figure 2.

Enzyme-linked immunosorbent assay (ELISA) analysis of specific antibody responses in low-and high-dose Burkholderia pseudomallei-infected mice. BALB/c mice were infected with 12 50% lethal doses (LD₅₀) (230 colony-forming units) (A) or 0.3 LD₅₀ (6 colony-forming units) (B) of B. pseudomallei by intraperitoneal injection. Plasma samples on hours or days indicated were collected and specific antibody to culture-filtered antigens were measured by ELISA. Results are expressed as mean ± SE (optical density at 450 nm). Mice injected with phosphate-buffered saline were used as control. Asterisks represent statistically significant differences (P < 0.05) compared with controls. Results were obtained from two independent experiments.