Rab27 promotes MIP-2 dependent neutrophil recruitment to the lungs in vivo . Wild-type (WT) and Rab27a/b double knockout (Rab27DKO) mice were treated with PBS vehicle or MIP-2 via intranasal administration and 2 hours after treatment, bronchoalveolar lavage (BAL) (A-C) and blood cells (D, E) were collected. BAL cells from wild-type and Rab27DKO mice treated with PBS and MIP-2 were collected, cytospun and differentially stained (A). Shown are representative images of BAL cells showing presence of neutrophils in MIP-2 treated WT mice and greatly reduced numbers in Rab27DKO mice (arrow). BAL cells were stained for Ly6G to quantify percentage neutrophil content by flow cytometry (B). Total cells and neutrophils collected from BAL of wild-type and Rab27DKO mice treated with PBS and MIP-2 were quantified (C). Circulating cells in blood drawn from PBS or MIP-2 treated wild-type and Rab27DKO mice were stained for Ly6G to assess proportion of total cells that were neutrophils by flow cytometry (D) and total numbers of circulating neutrophils could be quantified (E). * p ≤0.05, ** p ≤0.01 student’s t test. Error bars s.e.m. Data from PBS treated mice (n = 5 for wild-type and Rab27DKO) and MIP-2 treated mice (n = 5 for wild-type and n = 6 for Rab27DKO).