γδ T cell/endothelial cell interactions

Ruminant γδ T cells exhibit unique patterns of tissue- and inflammation-specific recruitment. Studies of other cells, such as αβ T cells and even neutrophils, have clearly shown that interactions with the vascular endothelium regulate the entry of these cells into tissues. The leukocyte/endothelial cell interaction is a dynamic event that occurs under considerable shear force associated with blood flow, and it involves a variety of adhesion molecules expressed by both the leukocyte and endothelium. We have begun a systematic analysis of γδ T cell interactions with endothelial and other cells in novel in vitro assays that reflect blood flow to gain insight into the molecular basis of the selective recruitment of these lymphocytes to epithelial-associated tissues and sites of inflammation. We have found that bovine γδ T cells in newborns predominantly use the selectin family of leukocyte and vascular adhesion proteins to interact with endothelial cells. This is in direct contrast to other lymphocytes, such as αβ T cells, which predominantly interact with selectins only after conversion to a memory cell phenotype. Our analyses of γδ T cell-selectin interactions will be summarized.