The basophil activation marker defined by antibody 97A6 is identical to the ectonucleotide pyrophosphatase/phosphodiesterase 3.
It has recently been shown that monoclonal antibody (MoAb) 97A6 detects a surface antigen expressed on basophils and their CD34(+) precursor cells, as well as the basophil cell line KU-812. In this report the partial amino acid sequence of affinity chromatography- and sodium dodecyl sulfate-polyacrylamide gel electrophoresis-separated 97A6 antigen(s) from KU-812 lysates was determined. Sequence alignment of high-performance liquid chromatography-selected tryptic peptides from the resulting 130- and 150-kd bands revealed a 100% identity with amino acids 393 to 405 of ectonucleotide pyrophosphatase/phosphodiesterase-3 (E-NPP3; CD203c) but not of the related ectoenzyme PC-1 (E-NPP1). Moreover, MoAb 97A6 selectively recognized 293 cells transfected with human E-NPP3, but did not react with cells transfected with PC-1 or parental 293 cells. In addition, E-NPP3 messenger RNA expression was detected in basophils but not other peripheral blood cells. Finally, MoAb 97A6 immunoprecipitated phosphodiesterase activity from KU-812 cells and peripheral blood basophils, but not from other cell populations. These data demonstrate that MoAb 97A6 recognizes the functionally active type II transmembrane ectoenzyme E-NPP3.
Bühring
H J
HJ
University of Tübingen, Department of Internal Medicine II, Division of Hematology, Immunology, and Oncology, Germany. hans-joerg.buehring@med.uni-tuebingen.de
Seiffert
M
M
Giesert
C
C
Marxer
A
A
Kanz
L
L
Valent
P
P
Sano
K
K
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis; D001491:Basophils / Q000201:enzymology / Q000276:immunology*; D015415:Biomarkers / Q000032:analysis*; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D002851:Chromatography, High Pressure Liquid; D015870:Gene Expression; D007163:Immunosorbent Techniques; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D043264:Phosphodiesterase I; D010727:Phosphoric Diester Hydrolases / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D011755:Pyrophosphatases / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D016415:Sequence Alignment; D014162:Transfection; D014357:Trypsin / Q000378:metabolism
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D015415:Biomarkers; C427944:ENPP3 protein, human; D010446:Peptide Fragments; D012333:RNA, Messenger; D010727:Phosphoric Diester Hydrolases; D043264:Phosphodiesterase I; D014357:Trypsin; D011755:Pyrophosphatases