A CD66a-specific, activation-dependent epitope detected by recombinant human single chain fragments (scFvs) on CHO transfectants and activated granulocytes.
Antibodies to CD66 recognize at least five members (CD66a-e) of the carcinoembryonic antigen (CEA) family. Recombinant human single-chain Fv fragments (scFvs) that bind specifically to CD66a (biliary glycoprotein) were obtained from a naive human scFv library. The scFvs bound to the N-domain of CD66a on Chinese hamster ovary (CHO) transfectants but did not bind to freshly isolated peripheral granulocytes or to dimethylsulfoxide-treated HL-60 cells. In contrast, scFvs bound well to granulocytes that were short-term activated with N-formyl-Met-Leu-Phe or phorbol 12-myristate 13-acetate and to human HL-60 cells that were treated with all-trans-retinoic acid to induce granulocytic differentiation. Quantification of antigenic sites showed that the activation-dependent CD66a epitopes were expressed on nearly all of the CD66a molecules on CHO-biliary glycoprotein transfectants, but they were detected only on a portion of the molecules on activated polymorphonuclear neutrophils and differentiated HL-60 cells. Binding of CD66a scFvs to their neoepitopes on prestimulated PMNs induced respiratory burst, suggesting that CD66a is capable of delivering transmembrane signals in these cells.
Jantscheff
P
P
Institute of Immunobiolog, Albert-Ludwigs-University Freiburg, Federal Republic of Germany.
Nagel
G
G
Thompson
J
J
Kleist
S V
SV
Embleton
M J
MJ
Price
M R
MR
Grunert
F
F
D000818:Animals; D015703:Antigens, CD / Q000032:analysis / Q000276:immunology*; D000943:Antigens, Differentiation / Q000032:analysis / Q000276:immunology*; D016466:CHO Cells; D015815:Cell Adhesion Molecules; D006224:Cricetinae; D000939:Epitopes; D018922:HL-60 Cells; D006367:HeLa Cells; D006801:Humans; D007128:Immunoglobulin Fragments / Q000276:immunology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D016897:Respiratory Burst; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
D015703:Antigens, CD; D000943:Antigens, Differentiation; C069847:CD66 antigens; D015815:Cell Adhesion Molecules; D000939:Epitopes; D007128:Immunoglobulin Fragments; D011994:Recombinant Proteins; C055966:immunoglobulin Fv; D009240:N-Formylmethionine Leucyl-Phenylalanine; D013755:Tetradecanoylphorbol Acetate