Analysis of bovine gamma delta T cell interactions with E-, P-, and L-selectin. Characterization of lymphocyte on lymphocyte rolling and the effects of O-glycoprotease.

In earlier studies, we found that bovine gamma delta T cells avidly bind and roll under physiologic flow on E- and P-selection. In this study, we have extended our analyses of shear interactions of gamma delta T cells and have found that once gamma delta T cells permanently bind to endothelial cell monolayers they can support continued rolling of newly arriving gamma delta T cells. Anti-L-selection Abs blocked gamma delta T cell rolling on immobilized gamma delta T cells, and it was L-selection on the rolling cell, not the bound cell, that mediated the interaction. We propose, as we have for neutrophils, that lymphocyte/lymphocyte rolling represents a mechanism for amplification of the extravasation process. Having defined P-, E-, and L-selectin interactions with gamma delta T cells, we tested the susceptibility of the ligands for these selectins to treatment with O-glycoprotease, a compound that selectively cleaves mucin-like selectin ligands. O-glycoprotease treatment of gamma delta T cells blocked their interaction with P-selectin, but not E-selectin. Rolling of O-glycoprotease-treated cells on bound untreated gamma delta T cells was unaffected; however, O-glycoprotease treatment of the bound gamma delta T cells blocked their capacity to support rolling interactions. These results define a new lymphocyte/selectin interaction that may be important in amplifying lymphocyte extravasation and suggest that gamma delta T cell ligands for P- and E-selectin are distinct, whereas ligands for P- and L-selectin may be similar.