PMN influx is required for MΦ recruitment during early cutaneous granuloma formation.

C57BL/6 mice pretreated with PMN-depleting mAb NIMP-R14 (intravenously, 100 μg, −1 hour) exhibit virtually no recruitment of MΦ to sites of PAG-induced CG formation compared with control Ab-treated mice. Numbers of PMNs (A) and MΦ (B) per CG were assessed 24 hours and 72 hours after injection of PAG. Data were pooled from 5 or more mice per treatment group and time point in 2 independent experiments. Data are shown as means ± SEMs (10⁶ cells/granuloma). ***P < .001. (C) PMNs were isolated from CGs 12 hours after injection of biogel and were stained for anti–neutrophil Ab clone 7/4 (black area, anti–neutrophil Ab; white area, isotype control). Purity of isolated PMNs was determined to be > 99%; one experiment of at least 5 is shown. In panel D, groups of 3 C57BL/6 mice were depleted from PMNs using mAb 7/4 (100 μg intravenously, at −6 hours and +18 hours), and CGs were reconstituted locally twice daily with 0.5 mL/granuloma of either vehicle alone or PMN supernatant (PMN-SPNT). MΦ numbers were determined after 48 hours and are expressed as means ± SEMs (10⁶ cells/granuloma). **P < .005. Data are representative of 3 independent experiments.