PMN secretion specifically mobilizes inflammatory monocytes. (A) Fluorescence intensity of extravasated monocytes in the musculus cremaster of CX3CR1^eGFP/+ mice after intrascrotal injection of PAF (10⁻⁶ M). High-fluorescent cells represent the resident monocytes, whereas low-fluorescent cells constitute the inflammatory monocytes. Analyses were made in mice with intact WBC count (top right), in neutropenic mice (middle right), and in neutropenic mice treated intrascrotally with PMN secretion (bottom right). Data are based on analyses in 10 cremaster muscles in each group. Representative images are shown to the right of each histogram. (B) Adhesion and extravasation of inflammatory monocytes in the musculus cremaster 12 hours after intrascrotal injection of PAF (10⁻⁶ M). Analyses were made in neutropenic C57BL/6 mice with or without local treatment with PMN secretion. Ingestion of fluorescent latex beads allowed visualization of the inflammatory monocyte subset. * indicates significant difference compared with PMN depl. (C) Recruitment of resident and inflammatory monocytes in the air pouch of C57BL/6 mice 12 hours after stimulation with PAF (10⁻⁶ M). The monocytes were differentiated by FACS based on their Gr1 expression. Analyses were made in mice with intact WBC count (ctrl), neutropenic mice (PMN depl), and neutropenic mice treated with PMN secretion (PMN depl + PMN-sec). ** indicates significant difference compared with both ctrl and PMN depl + PMN-sec.