Figure 9.

In vivo protective efficacy and capsule reactivity of V-region identical murine IgG subclass mAbs against Bacillus anthracis. (A) Overall survival of mAb-treated mice after receiving lethal dose of Bacillus anthracis spores. Only IgG3 mAbs were protective in a dose-dependent manner; treatment with IgG1, IgG2a, or IgG2b mAbs did not significantly increase the overall survival percentage at any given dose. (B) Incubation of Bacillus anthracis cells with each mAb variant and evaluation by differential interference contrast microscopy. The IgG3 mAbs produced dual-capsule binding reactions at both the outer edge (red arrow) and inner layer near the cell wall (blue arrow); the other subclass variants produced a “puffy” type of reaction where no reactivity to either region was observed. Figure reproduced from an open access article from.¹³³