Specific expression of GPR56 by human cytotoxic lymphocytes.

We here report the existence of a new cluster of adhesion-GPCRs in human immune cells. Analysis of a comprehensive immune cell transcriptome dataset indicated that expression of the closely related receptors, GPR56, GPR97, and GPR114, is associated with single lymphocyte and granulocyte subsets. Applying flow cytometric analysis with newly generated mAb, we show that expression of GPR56 is restricted to cytotoxic NK and T lymphocytes, including CD8(+), CD4(+), and γδ T cells. Primary infection with human CMV, which generates a vast population of CD8(+) T cells with an effector phenotype, induced a strong increase in GPR56 expression in virus-specific CD8(+) T cells that remained detectable during latency. In NK-92 cells, ectopic expression of GPR56 inhibited spontaneous and SDF-1-stimulated cell migration. Our data suggest that GPR56 expression is a common trait of human cytotoxic lymphocytes and might affect the migratory properties of these cells.