Characterization of a species of non-specific cross-reacting antigen (NCA) expressed by human monocytic cell lines: structure and expression during cell differentiation.
It has been documented that human monocytes/macrophages are reactive with antibodies directed to carcinoembryonic antigen (CEA) and non-specific cross-reacting antigens (NCAs), a group of glycoproteins antigenically cross-reactive with CEA, yet the molecules responsible for this antigenic activity have not been fully clarified. In the present study, among 7 myelomonocytic cell lines tested, 2 monoblastoid lines, U-937 and THP-1, were found to express NCA-50/90, a glycosylphosphatidylinositol-anchored cell-adhesion molecule chiefly expressed on granulocytes. The 2 cell lines showed a reaction pattern with 5 distinct anti-CEA and anti-NCA monoclonal antibodies, similar to that of CHO transfectants expressing recombinant NCA-50/90. Immunoprecipitation and SDS-PAGE analyses identified glycoproteins of about 95 and 55 kDa in U-937 and THP-1 cells, respectively. Deglycosylation of the 2 antigens with N-glycanase gave the same apparent molecular mass of about 45,000, which was also the same as that of the deglycosylated form of the recombinant NCA-50/90. Upon Northern-blot analysis, only one band of approximately 2.5 kb was detected in both cell lines with a cDNA probe for NCA-50/90, which has a broad specificity to the CEA gene family members. cDNA cloning demonstrated that the 2.5-kb clones encode the peptide of NCA-50/90. The expression of NCA-50/90 by U-937 and THP-1 was down-regulated at both the protein and mRNA levels during cell differentiation from monoblastoid to monocyte/macrophage-like cells induced by stimulation with phorbol 12-myristate 13-acetate. Our observations suggest that NCA-50/90 is a differentiation antigen of cells of the monocyte/macrophage lineage as well as of the granulocyte lineage.
Kuroki
M
M
Department of Biochemistry, School of Medicine, Fukuoka University, Japan.
Yamanaka
T
T
Matsuo
Y
Y
Ohtani
T
T
Matsuo
Y
Y
Minowada
J
J
Misumi
Y
Y
Oikawa
S
S
Nakazato
H
H
Matsuoka
Y
Y
D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000951:Antigens, Neoplasm / Q000032:analysis* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D002272:Carcinoembryonic Antigen / Q000235:genetics / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology; D003429:Cross Reactions / Q000276:immunology; D015536:Down-Regulation; D006801:Humans; D007938:Leukemia / Q000276:immunology / Q000473:pathology; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D009000:Monocytes / Q000166:cytology / Q000276:immunology; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured
D015214:Antigens, Differentiation, Myelomonocytic; D000951:Antigens, Neoplasm; D002272:Carcinoembryonic Antigen; D008562:Membrane Glycoproteins; D012333:RNA, Messenger