Gr-1 depletion abrogates CRAMP- and LL-37-, but not PG-1-, induced protection of C57BL/6 mice challenged s.c. with spores. Survival curves of mice injected i.p. with 50 µg of an anti-GR-1 mAb to deplete neutrophils or an isotype-matched control Ab. The following day, 5 LD50 (5 × 105) of spores were coadministered s.c. in 200 µl of PBS (A) or 50 µM solutions of PG-1 (B), CRAMP (C), or LL-37 (D), and survival was monitored for 10 days. Log rank tests were conducted to determine whether differences in survival were statistically relevant. n = 10 mice per group.