Expression of γδ T cell receptor on caprine globule leukocytes

Histochemical characteristics and immunological surface phenotypes of globule leukocytes (GLs) of normal goats were investigated in the intestine. In the small intestine, GLs were concentrated in the base of the villus and around the crypt, whereas in the cecum and colon they were randomly distributed. Their cytoplasmic granules exclusively stained with phosphotungstic acid hematoxylin, and were negative for peroxidase and histamine in contrast to those of subepithelial mast cells. The existence of chondroitin sulfate in some granules of GLs and heparin in most granules of mast cells were revealed by alcian blue staining and digestion with chondroitinase ABC. Isolated intestinal GLs were positive for T cell receptor (TcR) 1-N24 (γδ) and CD8α, and negative for WC1-N3 and WC1-N4. Cryostat sections of ileum revealed preferential intraepithelial distribution of both TcR1-N24+ cells and CD8+ cells. WC1-N3+ and WC1-N4+ cells were rarely seen in the epithelium and lamina propria. These results indicate that caprine GLs are a γδ T cell subset, which is a different cell population from WC1 positive γδ T cells.