Search

CN-121975012-A - Taci-targeted nano antibody and application thereof

CN121975012ACN 121975012 ACN121975012 ACN 121975012ACN-121975012-A

Abstract

The invention provides a nanometer antibody targeting human transmembrane activator and calmodulin nerve phosphatase interaction protein TACI and application thereof, wherein the antibody is derived from alpaca heavy chain antibody variable region. The anti-TACI single domain antibody NB38 is capable of high affinity, specific binding to human TACI, recognizing recombinant TACI proteins, recognizing TACI in its cell surface natural conformation, and partially blocking BAFF/APRIL signaling pathway. Based on the nano antibody, the invention constructs fusion protein, chimeric antigen receptor, effector cells expressing the chimeric antigen receptor, bispecific cell connector and other genetic engineering forms. The nanobody can be further extended to conjugated drug forms. The product of the invention can be used for mediating the directional recognition and killing of TACI positive cells, can be used as supplement and expansion of BCMA targeted therapy, and provides a new candidate technical scheme for targeted therapy of multiple myeloma and other TACI related diseases.

Inventors

  • CAI MENGHUA
  • Wang Yingdie
  • ZHANG JIANMIN
  • HE WEI
  • HU SHIKAI
  • ZHU YAN
  • CHEN HUI
  • XU YI
  • HU YU

Assignees

  • 国典(北京)医药科技有限公司
  • 中国医学科学院基础医学研究所

Dates

Publication Date
20260505
Application Date
20260407

Claims (20)

  1. 1. A TACI-targeted nanobody or antigen-binding fragment thereof, wherein the nanobody or antigen-binding fragment thereof satisfies one of the following: (1) Comprises an amino acid sequence shown in SEQ ID NO. 1; (2) Consists of an amino acid sequence shown in SEQ ID NO. 1, and (3) Comprises an amino acid sequence having at least 90% sequence identity to the amino acid sequence shown in SEQ ID NO. 1, and comprises a CDR1 having an amino acid sequence shown in SEQ ID NO. 18, a CDR2 having an amino acid sequence shown in SEQ ID NO. 19 and a CDR3 having an amino acid sequence shown in SEQ ID NO. 20.
  2. 2. An isolated nucleic acid molecule encoding the nanobody of claim 1 or an antigen-binding fragment thereof.
  3. 3. An expression vector comprising the nucleic acid molecule of claim 2 or expressing the nanobody of claim 1 or antigen-binding fragment thereof.
  4. 4. A host cell comprising the nucleic acid molecule of claim 2 or the expression vector of claim 3.
  5. 5. A fusion protein comprising the nanobody of claim 1 or an antigen-binding fragment thereof.
  6. 6. The fusion protein of claim 5, further comprising one or more of an Fc domain, an albumin binding domain, a long-acting peptide and a tag sequence linked to the nanobody or antigen binding fragment thereof, wherein the Fc domain is derived from human IgG1, igG2, igG4, or an engineered variant thereof.
  7. 7. A chimeric antigen receptor comprising an antigen recognition domain comprising the nanobody of claim 1 or an antigen-binding fragment thereof.
  8. 8. The chimeric antigen receptor according to claim 7, wherein the chimeric antigen receptor comprises, in order from N-terminus to C-terminus, a signal peptide, an antigen recognition domain, a hinge and/or spacer region, a transmembrane region and an intracellular signal transduction domain.
  9. 9. The chimeric antigen receptor according to claim 8, wherein the intracellular signaling domain comprises cd3ζ and further comprising one or more costimulatory domains selected from the group consisting of CD28, 4-1BB, OX40, ICOS, DAP10, and DAP 12.
  10. 10. The chimeric antigen receptor according to any one of claims 7-9, further comprising a second antigen recognition domain that targets BCMA.
  11. 11. An immune effector cell expressing the chimeric antigen receptor of any one of claims 7-10.
  12. 12. The immune effector cell of claim 11, wherein the immune effector cell is selected from one or more of γδ T cells, αβ T cells, peripheral blood T cells, NK cells, NKT cells, cytotoxic T lymphocytes, iPSC-derived immune cells, macrophages, dendritic cells, and combinations thereof.
  13. 13. A bispecific or multispecific cell connector, the cell connector comprising: (1) A tumor recognition terminal comprising the nanobody of claim 1 or an antigen-binding fragment thereof, and (2) An immune cell binding end capable of binding an immune effector cell surface molecule.
  14. 14. The cell connector of claim 13, wherein the immune cell binding end is capable of binding γδ TCR, CD3, CD16, NKp30, NKp46, NKG2D, or a combination thereof.
  15. 15. The cell connector of claim 13 or 14, further comprising a second tumor recognition end, the second tumor recognition end targeting BCMA.
  16. 16. A pharmaceutical composition comprising one or more of the nanobody of claim 1 or antigen-binding fragment thereof, the fusion protein of claim 5 or 6, the chimeric antigen receptor of any one of claims 7-10, the immune effector cell of claim 11 or 12, and the cell connector of any one of claims 13-15, and a pharmaceutically acceptable carrier or adjuvant.
  17. 17. Use of the nanobody or antigen-binding fragment thereof of claim 1, the nucleic acid molecule of claim 2, the expression vector of claim 3, the host cell of claim 4, the fusion protein of claim 5 or 6, the chimeric antigen receptor of any one of claims 7-10, the immune effector cell of any one of claims 11 or 12, the cell connector of any one of claims 13-15, or the pharmaceutical composition of claim 16 in the manufacture of a medicament for treating a TACI-positive disease.
  18. 18. The use according to claim 17, wherein the TACI-positive disease is selected from one or more of multiple myeloma, plasma cell tumor, B-cell lymphoma and autoimmune disease.
  19. 19. The use of claim 18, wherein the multiple myeloma is multiple myeloma that is heterogeneous in BCMA expression, reduced BCMA expression, or failed therapy related to BCMA.
  20. 20. The use of any one of claims 17-19, wherein the medicament is used in combination or sequentially with a BCMA targeting medicament, BCMA-CAR, BCMA-TCE, proteasome inhibitor, immunomodulator, monoclonal antibody, chemotherapeutic medicament, radiation therapy, or a combination thereof.

Description

Taci-targeted nano antibody and application thereof Technical Field The invention belongs to the technical field of biological medicine and tumor immunotherapy, and in particular relates to a targeting TACI-combined nano antibody or antigen binding fragment thereof, and nucleic acid, an expression vector, fusion protein, chimeric antigen receptor, bispecific cell connector and application thereof for encoding the nano antibody or antigen binding fragment thereof, wherein the nano antibody can be further expanded into a coupled drug form. Background Transmembrane activator and calcineurin interacting protein (Transmembrane Activator and CAML Interactor, TACI), also known as tumor necrosis factor receptor superfamily member 13B (tumor necrosis factor receptor superfamily member 13B, tnfrsf 13B), are mainly expressed in B cell lineage cells and are involved in humoral immune regulation. TACI binds B cell activating factor (BAFF) and proliferation inducing ligand (APRIL), playing a key role in B cell homeostasis, plasma cell differentiation and survival. BCMA (B Cell Maturation Antigen) has become a mainstream target in the field of Multiple Myeloma (MM) treatment, but antigen escape, antigen density decline and drug resistance recurrence remain recognized difficulties. Studies have shown that partial BCMA targets patients who relapse after treatment, and their tumor cells still retain TACI expression, making TACI a very potential alternative or complementary target. In the prior art, therapeutic molecules directed against TACI have focused mainly on TACI-Fc fusion proteins or conventional monoclonal antibodies, and a small number of CAR-T cells based on conventional antibody fragments. However, these molecules have problems of large molecular weight, limited tissue penetration, insufficient engineering flexibility, and the like. Nanobodies (VHHs) have the advantages of small molecular weight, stable structure, easy engineering and the like, but the prior art still lacks a nanobody capable of binding TACI with high affinity and specificity and suitable for development of a variety of engineering therapeutic platforms, such as CAR-T, TCE and further expandable conjugated drug forms. Therefore, a novel multi-platform adaptive high-affinity anti-TACI nano antibody is developed, and has important clinical value for overcoming the limitation of the existing BCMA targeted therapy and providing a novel therapeutic strategy for TACI related diseases such as multiple myeloma and the like. Disclosure of Invention Aiming at the defects in the prior art, the invention provides a nano antibody capable of specifically combining TACI and an antigen-binding fragment thereof, and a plurality of engineering application forms are constructed by taking the nano antibody as a core. The obtained anti-TACI nanobody NB38 can be combined with human TACI with high affinity and specificity, can recognize not only recombinant TACI protein, but also natural conformation TACI molecules on the surface of tumor cells, and can partially block the combination of BAFF/APRIL and TACI. Based on the nanobody, the invention further constructs fusion protein, chimeric Antigen Receptor (CAR), immune effector cells expressing the CAR, bispecific cell connector (TCE) and other functional molecules. The nanobody can be further extended to conjugated drug forms. The product can be used for mediating the directional recognition and killing of TACI positive cells, can be used as a candidate technical scheme for TACI targeted therapy in multiple myeloma, and can be particularly used as supplement and expansion of BCMA targeted therapy. The invention is realized mainly by the following technical scheme: in one aspect, the invention provides a TACI-targeted nanobody or antigen-binding fragment thereof that satisfies one of the following: (1) Comprises an amino acid sequence shown in SEQ ID NO. 1; (2) Consists of an amino acid sequence shown in SEQ ID NO. 1, and (3) Comprising an amino acid sequence having at least 90% sequence identity, preferably at least 95% sequence identity, more preferably at least 99% sequence identity to the amino acid sequence shown in SEQ ID NO. 1, and comprising CDR1 having an amino acid sequence shown in SEQ ID NO. 18 (DYGMG), CDR2 having an amino acid sequence shown in SEQ ID NO. 19 (GISWNAGSTYYAESVNG) and CDR3 having an amino acid sequence shown in SEQ ID NO. 20 (VPPQGN). In one aspect, the invention provides an isolated nucleic acid molecule encoding a nanobody or antigen-binding fragment thereof as described above. In one aspect, the invention also provides an expression vector comprising a nucleic acid molecule as described above or expressing a nanobody as described above or an antigen-binding fragment thereof. In one aspect, the invention also provides a host cell comprising a nucleic acid molecule as described above, or an expression vector, or capable of expressing a nanobody as described above, or an antigen-binding fragme