IDENTIFICATION OF A MANNOSE-ACETATE-SPECIFIC 87-KDA RECEPTOR RESPONSIBLE FOR HUMAN NK AND LAK ACTIVITY

Target cell recognition and cytotoxicity of human CD56(+)NK and LAK ce lls is readily inhibited by acetylated mannose. Two respective NK cell receptor;candidates were isolated from human leukocyte lysates by man nose acetate affinity chromatography. The 87-kDa receptor showed seque nce homologies with lactoferrin and the 59-kDa receptor represented a complex of two Ca-binding proteins MRP-8 and MRP-14 reportedly express ed only by cells of myeloid origin. The 87-kDa receptor exhibited hete rogeneity in isoelectric focusing and behaved entirely differently fro m lactoferrin. Preincubation of tumor target cells with the 87-kDa rec eptor inhibited competitively target cell recognition and cytotoxicity of human CD56(+)NK and LAK cells.