Administration of pep-tides i.p. to C57BL/6 mice causes recruitment of neutrophils. Mice were injected i.p. with 200 µl of PBS, LPS (20 µg), or peptides (50 µM), and the peritoneal cavity was lavaged 4 h later. A, Cell populations were determined based on the relative expression levels of the cell surface markers B220, CD5, Mac-1, CD11c, and Gr-1. B, The absolute numbers of myeloid cells (CD5−B220−) and immature (Mac-1highGr-1intermediate) and mature (Mac-1highGr-1high) neutrophils were significantly larger in mice that received peptides than those injected with PBS as determined by a one-way ANOVA with a Dunnett posttest. *, p < 0.05; **, p < 0.01; ***, p < 0.001.