Differential effect of E-selectin antibodies on neutrophil rolling and recruitment to inflammatory sites

The selectins are inducible adhesion molecules critically important for the inflammatory response. We investigate here the functional effects of three monoclonal antibodies (MoAbs) raised against murine E-selectin (9A9, 10E6, and 10E9.6) on neutrophil recruitment in vivo, leukocyte roiling and circulating leukocyte concentrations in vivo, and adhesion of myeloid cells to E-selectin transfectants and recombinant E-selectin-IgG fusion protein in vitro. MoAbs 9A9 and 10E6 map to the lectin and epidermal growth factor (EGF)-like domains of murine E-selectin, whereas 10E9.6 binds to the consensus repeat region. 10E9.6 blocked neutrophil recruitment in a model of thioglycollate-induced peritonitis in Balb/c mice by more than 90% but had no effect in C57BL/6 mice. 9A9 and 10E6 blocked neutrophil recruitment in this assay only when combined with a P-selectin antibody, 5H1. Neither 9A9 nor 10E9.6 alone blocked leukocyte rolling in tumor necrosis factor-α-treated venules of Balb/c mice, but 9A9 almost completely inhibited leukocyte rolling when combined with the function-blocking murine P-selectin MoAb, RB40.34. In contrast, 10E9.6 had no effect on leukocyte rolling in RB40.34-treated Balb/c or C57BL/6 mice. 10E9.6 did not affect adhesion of myeloid cells to E- selectin transfectants or attachment, rolling, and detachment of myeloid cells to murine E-selectin-IgG fusion protein. However, adhesion was completely blocked in the same assays by 9A9. Taken together, these results indicate that E-selectin serves a function, other than rolling, that appears to be critically important for neutrophil recruitment to inflammatory sites in Balb/c mice.