KLRK1 and neoplasm: However, Vδ1+ TCR and NKG2D do not share binding sites on MICA/B, and the strength of NKG2D-MICA/B binding is 1000-fold stronger than that of Vδ1+TCR-MICA/B.269 Despite discrepancies in their antigen recognition, both Vδ2 and Vδ1 T cells rely on secretion of the perforin/granzyme-B mediated secretory and death receptor (TRAIL/TRAIL-R, Fas/FasL) pathways to execute their anti-tumor cytotoxic activity.