Sensitive Multiplexed Quantitative Analysis of Autoantibodies to Cancer Antigens with Chemically S-Cationized Full-Length and Water-Soluble Denatured Proteins

Junichiro Futami, Hidenori Nonomura, Momoko Kido, Naomi Niidoi, Nao Fujieda, Akihiro Hosoi, Kana Fujita, Komako Mandai, Yuki Atago, Rie Kinoshita, Tomoko Honjo, Hirokazu Matsushita, Akiko Uenaka, Eiichi Nakayama, Kazuhiro Kakimi

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Abstract

Humoral immune responses against tumor-associated antigens (TAAs) or cancer/testis antigens (CTAs) aberrantly expressed in tumor cells are frequently observed in cancer patients. Recent clinical studies have elucidated that anticancer immune responses with increased levels of anti-TAA/CTA antibodies improve cancer survival rates. Thus, these antibody levels are promising biomarkers for diagnosing the efficiency of cancer immunotherapy. Full-length antigens are favored for detecting anti-TAA/CTA antibodies because candidate antigen proteins contain multiple epitopes throughout their structures. In this study, we developed a methodology to prepare purified water-soluble and full-length antigens by using cysteine sulfhydryl group cationization (S-cationization) chemistry. S-Cationized antigens can be prepared from bacterial inclusion bodies, and they exhibit improved protein solubility but preserved antigenicity. Anti-TAA/CTA antibodies detected in cancer patients appeared to recognize linear epitopes, as well as conformational epitopes, and because the frequency of cysteine side-residues on the epitope-paratope interface was low, any adverse effects of S-cationization were virtually negligible for antibody binding. Furthermore, S-cationized antigen-immobilized Luminex beads could be successfully used in highly sensitive quantitative-multiplexed assays. Indeed, patients with a more broadly induced serum anti-TAA/CTA antibody level showed improved progression-free survival after immunotherapy. The comprehensive anti-TAA/CTA assay system, which uses S-cationized full-length and water-soluble recombinant antigens, may be a useful diagnostic tool for assessing the efficiency of cancer immunotherapy.

Original languageEnglish
Pages (from-to)2076-2084
Number of pages9
JournalBioconjugate Chemistry
Volume26
Issue number10
DOIs
Publication statusPublished - Oct 21 2015

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ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Organic Chemistry
  • Pharmaceutical Science
  • Biomedical Engineering
  • Pharmacology

Cite this

Futami, J., Nonomura, H., Kido, M., Niidoi, N., Fujieda, N., Hosoi, A., Fujita, K., Mandai, K., Atago, Y., Kinoshita, R., Honjo, T., Matsushita, H., Uenaka, A., Nakayama, E., & Kakimi, K. (2015). Sensitive Multiplexed Quantitative Analysis of Autoantibodies to Cancer Antigens with Chemically S-Cationized Full-Length and Water-Soluble Denatured Proteins. Bioconjugate Chemistry, 26(10), 2076-2084. https://doi.org/10.1021/acs.bioconjchem.5b00328