Activation-dependent expression of the blood group-related Lewis Y antigenon peripheral blood granulocytes

The expression of the difucosyl-lactosamine type 2 oligosaccharide Lewis Y (LeY) on peripheral blood cells was investigated. As assessed by the reacti vity with the mouse anti-LeY monoclonal antibody (mAb) ABL 364 among circul ating blood cells, the expression of the LeY oligosaccharide was uniquely r estricted to granulocytes. Although the density of LeY expressed on resting granulocytes was weak, in vitro activation of granulocytes with fMLP induc ed a rapid and pronounced increase in granulocyte LeY expression. Analysis of CEA-related glycoproteins immunoprecipitated with anti-CD66 mAbs followe d by immunoblotting with mAb ABL 364! showed that granulocyte LeY is attach ed to members of the CD66 cluster, in particular to the 160/90 kD glycoprot ein recognized by anti-CD66 mAb CBL/gran 10, The activation-associated incr ease in LeY attached to CD66 adhesion molecules implicates a role of the Le Y determinant in the cytoadhesive properties of granulocytes.