ANALYSIS OF HETEROPHILIC CELL-ADHESION MEDIATED BY CD66B AND CD66C USING THEIR SOLUBLE RECOMBINANT PROTEINS

The heterophilic cell adhesion mediated by CD66b (carcinoembryonic ant igen (CEA) gene Family member 6, CGM6) and CD66c (nonspecific cross-re acting antigen, NCA), both CEA family members expressed on neutrophils , was investigated using their soluble recombinant proteins prepared i n silkworm larvae. The recombinant CD66b and CD66c immobilized on plas tic bound CHO transfectants expressing CD66c and CD66b, respectively. Their deglycosylated forms retained the adhesion activity, suggesting that their carbohydrate portions are not prerequisite for the binding. This cell adhesion appeared to be mediated via interaction between th e N domains of CD66b and CD66c, because CD66 antibodies recognizing th eir N domains inhibited the binding. Neutrophils, when activated, adhe red to the immobilized CD66b and CD66c. In addition, the binding of pr imed neutrophils to the antigens induced superoxide anion release. The cell adhesion mediated by CD66b and CD66c may play a role in interact ion between neutrophils or between neutrophils and epithelial cells ex pressing CD66c in vivo. (C) 1996 Academic Press, Inc.