Identification of autoantigens presented by specific HLA class I alleles in aplastic anemia

• Project/Area Number: 19H03686
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 54010:Hematology and medical oncology-related
• Research Institution: Kanazawa University
• Principal Investigator: NAKAO Shinji 金沢大学, 医学系, 協力研究員 (70217660)
• Co-Investigator(Kenkyū-buntansha): 橋本 真一 和歌山県立医科大学, 先端医学研究所, 教授 (00313099) ; 細道 一善 金沢大学, 医学系, 准教授 (50420948) ; 岸 裕幸 富山大学, 学術研究部医学系, 教授 (60186210)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥17,550,000 (Direct Cost: ¥13,500,000、Indirect Cost: ¥4,050,000); Fiscal Year 2021: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000); Fiscal Year 2020: ¥5,850,000 (Direct Cost: ¥4,500,000、Indirect Cost: ¥1,350,000); Fiscal Year 2019: ¥8,320,000 (Direct Cost: ¥6,400,000、Indirect Cost: ¥1,920,000)
• Keywords: 再生不良性貧血 / 自己抗原 / HLA-B*40:02 / T細胞レセプター / 発作性夜間ヘモグロビン尿症 / HLA-DR15 / HLA / 細胞傷害性T細胞 / モノクローナル抗体 / T cell receptor (TCR） / TCRトランスフェクタント / 末梢血造血幹前駆細胞 / シクロスポリン / T細胞レセプタートランスフェクタント / HLAクラスI欠失血球 / T cell receptor / TCR transfectant

Outline of Research at the Start

再生不良性貧血（再不貧）は、造血幹前駆細胞（hematopoietic stem progenitor cell: HSPC）に対する細胞傷害性T細胞（cytotoxic T lymphocyte: CTL）の攻撃がきっかけとなって発症する自己免疫疾患である。しかし、CTLの標的となるHSPC上の自己抗原は未だに同定されていない。本研究では、申請者らが同定した「自己抗原提示に関わるHLAクラスIアレル」と、自己の造血幹細胞を傷害するCTLから同定したT細胞レセプターα/β鎖や、HSPC固有の蛋白を利用することにより、再不貧の自己抗原を同定する。

Outline of Final Research Achievements

To identify an autoantigen presented by HLA-B4002 on hematopoietic stem progenitor cells (HSPCs) of patients with acquired aplastic anemia (AA), we established T-cell receptor (TCR) transfectants using T cells from healthy individuals and TCR cDNA derived from T cells that predominantly proliferated in the bone marrow of an AA patient carrying HLA-B*40:02, and examined specific response to peptides bound to HLA-B4002 on a leukemia cell line K562 that were transfected with HLA-B*40:02. Two kinds of TCR transfectants specifically recognized one of the HLA-B4002-bound peptides that are derived from a cytoplasmic protein (protein X), which is abundantly expressed by HSPCs. We prepared a peptide-HLA-B4002 tetramer and are now screening peripheral blood T cells of AA patients with HLA-B*40:02 for the presence of the peptide-specific CD8+ T cells.
In a separate experiment, we found that HSPCs of AA patients possessing HLA-DR15 frequently lacked HLA-DR through epigenetic mechanisms.

Academic Significance and Societal Importance of the Research Achievements

AAは、HSPCに対する細胞傷害性T細胞の攻撃がきっかけとなって発症する自己免疫疾患である。しかし、細胞傷害性T細胞の標的となるHSPC上の自己抗原は不明であった。今回同定したX蛋白由来ペプチドに特異的なCD8+ T細胞が、HLA-B*40:02陽性AA患者の末梢血に検出され、さらにそのCD8+ T細胞の自己HSPCに対する細胞傷害性が証明されれば、X蛋白はAAにおける自己抗原であると考えられる。それが証明されれば、HLA-B4002-ペプチドテトラマーを用いたAAの特異的診断や、テトラマー陽性T細胞を標的とする選択的な治療法の開発などが可能となることが期待される。

Research Products

• [Journal Article] Frequent HLA-DR loss on hematopoietic stem progenitor cells in patients with cyclosporine-dependent aplastic anemia carrying HLA-DR15 (2022)
  • Author(s): Tsuji N, Hosokawa K, Urushihara R, Tanabe M, Katagiri T, Ozawa T, Takamatsu H, Ishiyama K, Yamazaki H, Kishi H, Ogawa S, Nakao S
  • Journal Title: Leukemia Volume: in press
  • Peer Reviewed
• [Journal Article] The GPI-anchored protein CD109 protects hematopoietic progenitor cells from undergoing erythroid differentiation induced by TGF-β (2021)
  • Author(s): Tanabe Mikoto、Hosokawa Kohei、Nguyen Mai Anh Thi、Nakagawa Noriharu、Maruyama Kana、Tsuji Noriaki、Urushihara Ryota、Espinoza Luis、Elbadry Mahmoud I.、Mohiuddin Md、Katagiri Takamasa、Ono Masanori、Fujiwara Hiroshi、Chonabayashi Kazuhisa、Yoshida Yoshinori、Yamazaki Hirohito、Hirao Atsushi、Nakao Shinji
  • Journal Title: Leukemia Volume: 36 Issue: 3 Pages: 847-855
  • DOI: 10.1038/s41375-021-01463-3
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Hematopoietic stem progenitor cells lacking HLA differ from those lacking GPI-anchored proteins in the hierarchical stage and sensitivity to immune attack in patients with acquired aplastic anemia (2021)
  • Author(s): Yoroidaka T, Hosokawa K, Imi T, Mizumaki H, Katagiri T, Ishiyama K, Yamazaki H, Azuma F, Nanya Y, Ogawa S, Nakao S
  • Journal Title: Leukemia Volume: in press Issue: 11 Pages: 3257-3267
  • DOI: 10.1038/s41375-021-01202-8
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] A frequent nonsense mutation in exon 1 across certain HLA-A and -B alleles in leukocytes of patients with acquired aplastic anemia. (2020)
  • Author(s): Mizumaki H, Hosomichi K, Hosokawa K, Yoroidaka T, Imi T, Zaimoku Y, Katagiri T, Nguyen MAT, Tran DC, Elbadry MIY, Chonabayashi K, Yoshida Y, Takamatsu H, Ozawa T, Azuma F, Kishi H, Fujii Y, Ogawa S, Tajima A, Nakao S.
  • Journal Title: Haematologica Volume: － Issue: 6 Pages: 247809-247809
  • DOI: 10.3324/haematol.2020.247809
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Clonal hematopoiesis by SLIT1-mutated hematopoietic stem cells due to a breakdown of the autocrine loop involving Slit1 in acquired aplastic anemia (2019)
  • Author(s): Hosokawa K, Mizumaki H, Elbadry M, Saito C, Espinoza JL, An DTT, Katagiri T, Harashima A, Kikuchi A, Kanai A, Matsui H, Inaba T, Taniwaki M, Yamamoto Y, Nakao S
  • Journal Title: Leukemia Volume: 33 Issue: 11 Pages: 2732-2766
  • DOI: 10.1038/s41375-019-0510-0
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Clonal hematopoiesis by HLA class I allele-lacking hematopoietic stem cells and concomitant aberrant stem cells is rarely associated with clonal evolution to MDS/AML in patients with acquired aplastic anemia (2020)
  • Author(s): Hosokawa K, Mizumaki H, Yoroidaka T, Maruyama H, Imi T, Tsuji N, Urushihara R, Tanabe M, Zaimoku Y, Nguyen MAT, Tran DC, Ishiyama K, Yamazaki H, Katagiri T, Takamatsu H, Hosomichi K, Tajima A, Azuma F, Ogawa S, Nakao S
  • Organizer: 62nd Annual Meeting of American Society of Hematology
  • Int'l Joint Research
• [Presentation] A Common HLA Allelic Mutation of exon1 in Leukocytes Defines Class I Alleles Responsible for Autoantigen Presentation of Acquired Aplastic Anemia (2019)
  • Author(s): Hiroki Mizumaki
  • Organizer: 61st American Society of HematologyAnnual Meeting and Exposition
• [Presentation] Identification of T-Cell Receptors Specific to Antigens Presented By HLA-B4002 and B5401 in Acquired Aplastic Anemia (2019)
  • Author(s): Kohei Hosokawa
  • Organizer: 61st American Society of HematologyAnnual Meeting and Exposition