(A) TEM of neutrophils infected with wild-type B. anthracis (arrow) at an MOI of 1:1. Bar = 1μm. Inset indicates the inoculum. Bar = 100 nm.
(B) Scanning electron microscopy of neutrophils infected with vegetative form of the toxin-producing strain for 30 min. Phagocytosed bacteria shown by arrow. Neutrophils efficiently engulf B. anthracis despite their size. Bar = 5μm.
(C) Neutrophils kill B. anthracis efficiently. Activated neutrophils were infected with wild-type, capsule-, or toxin-expressing vegetative bacteria for indicated time points at an MOI of 10:1.
(D) B. anthracis capsule and toxin are not antiphagocytic. Activated neutrophils were pretreated with the phagocytosis inhibiting cytochalsin D (10 μg/ml), infected with wild-type, capsule-, or toxin-expressing vegetative bacteria at an MOI of 1:1, and incubated for 30 min.