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Identification of the heterogeneous nuclear ribonucleoprotein A2/B1 as the antigen for the gastrointestinal cancer specific monoclonal antibody MG7
Author(s) -
Lee Chiho,
Lum John Honkei,
Cheung Belinda Pikyuen,
Wong Mansau,
Butt Yoki Kwokchu,
Tam Ming F.,
Chan Wing Y.,
Chow Chit,
Hui Pakkwan,
Kwok Francis S. L.,
Lo Samuel Chunlap,
Fan D. M.
Publication year - 2005
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200401159
Subject(s) - monoclonal antibody , microbiology and biotechnology , antigen , antibody , ribonucleoprotein , western blot , biology , cell nucleus , heterogeneous nuclear ribonucleoprotein , small nuclear ribonucleoprotein , biochemistry , nucleus , immunology , gene , rna
MG7 is an early gastrointestinal cancer specific monoclonal antibody. It can detect gastric cancer with high sensitivity and specificity. However, the target antigen for MG7 has not been identified. Western blot analysis revealed that the MG7 antibody reproducibly recognized two ∼35 kDa proteins in the total cell lysates of human gastric carcinoma cell lines KATO III and MKN‐45. Using a proteomic approach, we identified these MG7 immunoreactive proteins as the human heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1). Western blot analysis of nuclear and cytosolic fraction of KATO III cells using either MG7 or hnRNP A2/B1 antibodies confirmed that the target antigen is located exclusively in the nucleus. With the use of archival samples, we also found that the level of hnRNP A2/B1 protein was increased in gastric cancer tissues (4 out of 5 patients), when compared to their corresponding matching normal stomach tissue.