Molecular cloning of bovine chemokine receptors and expression by WC1⁺ γδ T cells

Chemokine receptors mediate leukocyte migration into secondary lymphoid tissues and localization to peripheral inflammation sites. We describe full-length cDNA sequences of bovine chemokine receptors CCR5, CCR7, CXCR3 and CXCR5 and transcript expression by WC1⁺ γδ T cells, a unique cell population with proinflammatory characteristics that comprises a large proportion of mononuclear cells in young ruminants. Bovine chemokine sequences were more similar to those of humans than were murine sequences to humans', ranging from 84% to 91%. Transcript analysis showed that antigen stimulation of WC1⁺ γδ T cells induced IFN-γ production and substantially increased CCR5 and CXCR3 expression when compared with freshly isolated (ex vivo) cells. CCR7 transcripts were minimally expressed in ex vivo and proliferating WC1⁺ γδ T cells and CXCR5 expression was negligible. These results confirm the proinflammatory nature of WC1⁺ γδ T cells is reflected by its chemokine receptor expression and suggest WC1⁺ γδ T cells are unlikely to transit through secondary lymphoid tissues.