Figure 6. Immunogenicity in mice of control and heat-stressed DNI. (A) rPA-specific endpoint titers and (B) toxin-neutralizing titers in the sera of mice immunized with either a high (H, 10 µg) or low (L, 1 µg) dose of DNI that had been stored at 4 °C (H1 and L1), 40 °C for 2 weeks (H2 and L2) or 4 weeks (H4 and L4), or 70 °C for 2 weeks (H3 and L3) or 4 weeks (H5 and L5) were bled after the second (blue circles) and third (red squares) immunization. (C) PA-specific endpoint titers and (D) neutralizing titers in the sera of mice immunized with either DNI or rPA at doses of 1 µg and 10 µg.