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CN-120157768-B - Monoclonal antibody for recognizing FLT3-CAR molecule and application thereof

CN120157768BCN 120157768 BCN120157768 BCN 120157768BCN-120157768-B

Abstract

The invention provides a monoclonal antibody for recognizing FLT3-CAR molecules and application thereof, wherein the amino acid sequence of a heavy chain CDR3 of the monoclonal antibody is shown as SEQ ID NO. 4, SEQ ID NO. 12 or SEQ ID NO. 19, and the amino acid sequence of a light chain CDR3 of the monoclonal antibody is shown as SEQ ID NO. 8, SEQ ID NO. 15 or SEQ ID NO. 22. The monoclonal antibody can specifically identify FLT3-CAR molecules on FLT3-CAR-T cells, has no cross reaction with other molecules, has high binding activity with the FLT3-CAR molecules, develops a flow analysis method for detecting the CAR transfection positive rate of the FLT3-CAR-T cells, and can accurately and specifically detect the transfection efficiency of the FLT3-CAR molecules.

Inventors

  • YANG LIN
  • WANG MIN
  • XIA SHANWEI
  • YOU FENGTAO
  • XIA JINXIN

Assignees

  • 博生吉安科细胞技术有限公司

Dates

Publication Date
20260505
Application Date
20231215

Claims (9)

  1. 1. A monoclonal antibody for recognizing FLT3-CAR molecules is characterized in that the amino acid sequence of a heavy chain CDR1 of the monoclonal antibody is shown as SEQ ID NO. 2, the amino acid sequence of the CDR2 is shown as SEQ ID NO. 3, the amino acid sequence of the CDR3 is shown as SEQ ID NO.4, the amino acid sequence of a light chain CDR1 of the monoclonal antibody is shown as SEQ ID NO. 6, the amino acid sequence of the CDR2 is GTS, and the amino acid sequence of the CDR3 is shown as SEQ ID NO. 7.
  2. 2. The monoclonal antibody recognizing FLT3-CAR molecule according to claim 1, characterized in that the heavy chain variable region amino acid sequence of said monoclonal antibody is shown in SEQ ID No. 1.
  3. 3. The monoclonal antibody recognizing FLT3-CAR molecule according to claim 1, characterized in that the light chain variable region amino acid sequence of said monoclonal antibody is shown in SEQ ID No. 5.
  4. 4. A monoclonal antibody recognizing FLT3-CAR molecule according to any one of claims 1-3, wherein the heavy chain variable region amino acid sequence of said monoclonal antibody is shown in SEQ ID No. 1 and the light chain variable region amino acid sequence is shown in SEQ ID No. 5.
  5. 5. A nucleic acid molecule encoding the monoclonal antibody of any one of claims 1-4 that recognizes a FLT3-CAR molecule.
  6. 6. Use of a monoclonal antibody that recognizes a FLT3-CAR molecule according to any one of claims 1-4 in the preparation of a reagent for detecting a CAR molecule of a FLT3-CAR-T cell.
  7. 7. A pharmaceutical composition comprising the monoclonal antibody of any one of claims 1-4 that recognizes a FLT3-CAR molecule.
  8. 8. The pharmaceutical composition of claim 7, wherein, the pharmaceutical composition further comprises a pharmaceutically acceptable carrier.
  9. 9. A kit for detecting a FLT3-CAR molecule in a sample, comprising a monoclonal antibody that recognizes the FLT3-CAR molecule of any one of claims 1-4.

Description

Monoclonal antibody for recognizing FLT3-CAR molecule and application thereof Technical Field The invention belongs to the technical field of biological medicine, and particularly relates to a monoclonal antibody for recognizing FLT3-CAR molecules and application thereof. Background Acute myelogenous leukemia (Acute myeloid leukemia, AML) is a highly heterogeneous myeloid hematopoietic stem/progenitor malignancy, one of the most common types of leukemia in adults, accounting for about half of all leukemia patients. AML is mainly characterized by abnormal proliferation of primary and naive myelogenous cells in marrow and peripheral blood, and clinical symptoms mainly include anemia, hemorrhage, infection, fever, viscera infiltration, metabolic abnormality and the like, and the AML has rapid progress, extremely invasive performance, urgent and serious illness state of most cases and serious prognosis, and can endanger life if not treated in time. In recent years, chimeric antigen Receptor T cells (CHIMERIC ANTIGEN Receptor T-Cell, CAR-T) have shown significant clinical efficacy in the treatment of relapsed refractory lymphomas. The CAR-T therapy is to activate T lymphocytes of patients and then chimeric specific tumor antigen receptor genes through a gene modification technology to form modified T cells, so that antigens on the surfaces of tumor cells can be specifically identified and combined to realize specific killing of the tumor cells. One of the key to the success of this technology is the selection of an appropriate target antigen, which can be precisely targeted to kill tumors by constructing the corresponding CAR molecule. The optimal target antigen should be expressed only in tumor cells and not in normal cells. FLT3 (FMS-like tyrosine kinase 3) is one of the class III receptor tyrosine kinases. FLT3 is a transmembrane protein that includes 5 immunoglobulin-like domains in the extracellular domain. Many studies have demonstrated that activating mutations in FLT3 play a very important pathological role in the development of AML and in the progression of disease, and that mutant FLT3 induces abnormal activation of various intracellular signaling pathways, disrupting proliferation, differentiation and apoptosis of normal hematopoietic cells, leading to the development of leukemia. Mutations leading to constitutive activation of FLT3 have been observed in acute myelogenous leukemia and acute lymphoblastic leukemia. The method for targeted treatment of acute myeloid leukemia by FLT3-CAR-T cells is developed by the skilled in the art, but the currently disclosed targeted FLT3 antibody can only recognize specific FLT3 antigen and cannot detect CAR transfection efficiency of CAR-T cells, so that the monoclonal antibody capable of accurately detecting CAR transfection efficiency is provided, and has important significance in targeted treatment of acute myeloid leukemia. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide a monoclonal antibody for recognizing FLT3-CAR molecules and application thereof. The monoclonal antibody for recognizing the FLT3-CAR molecule can specifically recognize the FLT3-CAR molecule on the FLT3-CAR-T cell, has no cross reaction with other molecules, has high binding activity with the FLT3-CAR molecule, and can accurately detect the CAR transfection efficiency. In order to achieve the aim of the invention, the invention adopts the following technical scheme: In a first aspect, the invention provides a monoclonal antibody that recognizes a FLT3-CAR molecule, wherein the amino acid sequence of the heavy chain CDR3 of the monoclonal antibody is shown as SEQ ID NO. 4, SEQ ID NO. 11 or SEQ ID NO. 18; the amino acid sequence of the light chain CDR3 of the monoclonal antibody is shown as SEQ ID NO. 7, SEQ ID NO. 14 or SEQ ID NO. 21. Preferably, the amino acid sequence of the heavy chain CDR1 of the monoclonal antibody is shown as SEQ ID NO. 2, SEQ ID NO. 9 or SEQ ID NO. 16. Preferably, the amino acid sequence of the heavy chain CDR2 of the monoclonal antibody is shown as SEQ ID NO. 3, SEQ ID NO. 10 or SEQ ID NO. 17. Preferably, the amino acid sequence of the light chain CDR1 of the monoclonal antibody is shown as SEQ ID NO. 6, SEQ ID NO. 13 or SEQ ID NO. 20. Preferably, the amino acid sequence of the light chain CDR2 of the monoclonal antibody is selected from GTS or GAS. Preferably, the amino acid sequence of the heavy chain CDR1 of the monoclonal antibody is shown as SEQ ID NO.2, the amino acid sequence of the CDR2 is shown as SEQ ID NO. 3, the amino acid sequence of the CDR3 is shown as SEQ ID NO. 4, the amino acid sequence of the light chain CDR1 of the monoclonal antibody is shown as SEQ ID NO. 6, the amino acid sequence of the CDR2 is GTS, and the amino acid sequence of the CDR3 is shown as SEQ ID NO. 7; Or the amino acid sequence of the heavy chain CDR1 of the monoclonal antibody is shown as SEQ ID NO. 9, the amino acid sequence o