these same enzyme-pretreated target cells , however , were unaffected in their ability to bind a natural killer cell-derived cytolytic factor ( nkcf ) molecule ( s ) , as determined by direct nkcf absorption studies or by their ability to cold target compete for the binding of nkcf to another nkcf-sensitive cell , the l929 fibroblast , thereby indicating that the k562 `` '' target antigen '' '' and the nkcf-receptor are independently expressed structures .
C0022688
nkcf
C0382839
nkcf-recept