Bovine gamma/delta T cells bind E-selectin via a novel glycoprotein receptor: first characterization of a lymphocyte/E-selectin interaction in an animal model.
E-Selectin is an inducible adhesion protein expressed by endothelial cells and recognized by leukocytes during their extravasation from the blood into inflamed tissues. Originally, E-selectin was defined as a myeloid cell-specific adhesion protein, but recent studies have shown it to be recognized by human lymphocytes as well. These lymphocytes represent a memory T cell subset and have been shown to express the HECA-452 carbohydrate epitope (CLA+ lymphocytes). We extend these findings and show that ruminant gamma/delta T cells bind E-selectin as well; and we provide preliminary evidence that this interaction is mediated by a novel glycoprotein receptor on the lymphocyte. Unlike conventional T cells (alpha/beta T cells), gamma/delta T cells from neonatal and mature animals bind E-selectin, suggesting that prior antigen stimulation and differentiation to a memory lymphocyte are not required for this interaction. Neuraminidase treatment of the gamma/delta T cells or addition of ethylenediaminetetraacetic acid (EDTA) to the assay abrogates binding, demonstrating the importance of sialic acid and divalent cations, which is consistent with other E-selectin-mediated adhesion events. However, previously defined E-selectin carbohydrate ligands, such as sialyl Lewis x on neutrophils and the HECA-452 epitope on human memory lymphocytes, are antigenically different than the carbohydrates on ruminant gamma/delta T cells since the mAbs CSLEX and HECA-452 do not recognize these cells. Protease treatment of gamma/delta T cells significantly inhibits their binding to E-selectin; however, previously characterized adhesion glycoproteins, such as L-selectin, CD44, and CD18, are not involved in the adhesive event. An E-selectin affinity column purifies a single glycoprotein of 250 kD (280 kD under reducing conditions) from gamma/delta T cell detergent lysates. Neuraminidase digestion of the 250-kD product as well as EDTA abolishes binding to E-selectin. Finally, E-selectin expression in vivo appears to mediate gamma/delta T cell accumulation. Stimulation of bovine skin with tumor necrosis factor alpha induced an increase in E-selectin expression that was associated with an influx of gamma/delta T cells at the same site.
Walcheck
B
B
Veterinary Molecular Biology, Montana State University, Bozeman 59717.
Watts
G
G
Jutila
M A
MA
D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D019040:E-Selectin; D006023:Glycoproteins / Q000378:metabolism; D019158:N-Acetylneuraminic Acid; D011485:Protein Binding; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012794:Sialic Acids / Q000378:metabolism; D012867:Skin / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000166:cytology*; D014162:Transfection; D015854:Up-Regulation
D015815:Cell Adhesion Molecules; D019040:E-Selectin; D006023:Glycoproteins; D016692:Receptors, Antigen, T-Cell, gamma-delta; D011994:Recombinant Proteins; D012794:Sialic Acids; D019158:N-Acetylneuraminic Acid