Sensitive Multiplexed Quantitative Analysis of Autoantibodies to Cancer Antigens with Chemically S-Cationized Full-Length and Water-Soluble Denatured Proteins.
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.
Department of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University , Okayama 700-8530, Japan.
Junichiro
J
Futami
Department of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University , Okayama 700-8530, Japan.
Hidenori
H
Nonomura
Department of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University , Okayama 700-8530, Japan.
Momoko
M
Kido
Department of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University , Okayama 700-8530, Japan.
Naomi
N
Niidoi
Medinet Co. Ltd. , Yokohama, Kanagawa 222-0033, Japan.|Department of Immunotherapeutics, The University of Tokyo Hospital , Tokyo 113-8655, Japan.
Nao
N
Fujieda
Medinet Co. Ltd. , Yokohama, Kanagawa 222-0033, Japan.|Department of Immunotherapeutics, The University of Tokyo Hospital , Tokyo 113-8655, Japan.
Akihiro
A
Hosoi
Department of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University , Okayama 700-8530, Japan.
Kana
K
Fujita
Department of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University , Okayama 700-8530, Japan.
Komako
K
Mandai
Department of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University , Okayama 700-8530, Japan.
Yuki
Y
Atago
Department of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University , Okayama 700-8530, Japan.
Rie
R
Kinoshita
Department of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University , Okayama 700-8530, Japan.
Tomoko
T
Honjo
Department of Immunotherapeutics, The University of Tokyo Hospital , Tokyo 113-8655, Japan.
Hirokazu
H
Matsushita
Faculty of Health and Welfare, Kawasaki University of Medical Welfare , Kurashiki, Okayama 701-0193, Japan.
Akiko
A
Uenaka
Faculty of Health and Welfare, Kawasaki University of Medical Welfare , Kurashiki, Okayama 701-0193, Japan.
Eiichi
E
Nakayama
Department of Immunotherapeutics, The University of Tokyo Hospital , Tokyo 113-8655, Japan.
Kazuhiro
K
Kakimi
D000951:Antigens, Neoplasm / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D001323:Autoantibodies / Q000032:analysis* / Q000378:metabolism; D002412:Cations / Q000737:chemistry; D018572:Disease-Free Survival; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D006801:Humans; D055767:Immobilized Proteins / Q000737:chemistry / Q000276:immunology; D007118:Immunoassay / Q000379:methods*; D009369:Neoplasms / Q000276:immunology* / Q000401:mortality; D011489:Protein Denaturation; D012680:Sensitivity and Specificity; D012995:Solubility; D013455:Sulfur / Q000737:chemistry
D000951:Antigens, Neoplasm; D001323:Autoantibodies; D002412:Cations; D000939:Epitopes; D055767:Immobilized Proteins; D013455:Sulfur