Accelerated neutrophil emigration in Adam17^−/− chimeras after thioglycollate injection is completely blocked by the administration of L-selectin antibody, but MEL-14 has no effect on monocyte influx. Fab fragments of the blocking L-selectin antibody MEL-14 or control IgG (30 μg/mouse) were administered just before thioglycollate injection. (A) MEL-14 completely blocked the accelerated neutrophil emigration in Adam17^−/− chimeras (n = 5 per group except Adam17^+/+ with MEL-14, n = 4). Replicate experiments showed identical results. (B) Monocyte influx into the peritoneal cavity at 16 hours as described in the legend to Figure 4 was not altered by treatment with MEL-14 Fab. All data are expressed as means ± SD.