Isolated antigen-binding protein and application thereof
An isolated antigen-binding protein, having one or more of the following properties: 1) capable of binding to human and monkey-derived GITR proteins at a K D value of 7×10 −12 or below, wherein the K D value is measured by BLI method; 2) capable of stimulating immune cell proliferation; 3) capable of stimulating immune cells to secrete IFN-γ, wherein the secretion is measured in T cell viability assay; 4) capable of inhibiting tumor growth and/or tumor cell proliferation; 5) capable of activating GITR signaling pathway; 6) capable of inhibiting the binding of GITR to GITRL.
1 . An isolated antigen-binding protein, having one or more of the following properties:
1) Capable of binding to human and monkey-derived GITR proteins at a K D value of 7×10 −12 M or below, wherein the K D value is measured by Bio-Layer Interferometry (BLI) method;
2) capable of stimulating immune cell proliferation;
3) capable of stimulating immune cells to secrete IFN-γ, wherein the secretion is measured in T cell viability assay;
4) capable of inhibiting tumor growth and/or tumor cell proliferation;
5) capable of activating GITR signaling pathway;
6) capable of inhibiting the binding of GITR to GITRL,
wherein VH of the isolated antigen-binding protein comprises HCDR3 as set forth in SEQ ID NO: 4, HCDR1 as set forth in SEQ ID NO: 2, and HCDR2 as set forth in SEQ ID NO: 3, and
wherein VL of the isolated antigen-binding protein comprises LCDR1 as set forth in SEQ ID NO: 10, LCDR2 as set forth in SEQ ID NO: 11, and LCDR3 as set forth in SEQ ID NO: 12.
2 . The isolated antigen-binding protein according to claim 1 , wherein the VL comprises framework regions L-FR1, L-FR2, L-FR3, and L-FR4, wherein a C-terminus of the L-FR1 is directly or indirectly linked to an N-terminus of the LCDR1, wherein the L-FR1 comprises an amino acid sequence as shown in any one of SEQ ID NOs: 13, 30, 34.
3 . The isolated antigen-binding protein according to claim 2 , wherein the L-FR2 is located between the LCDR1 and the LCDR2, and the L-FR2 comprises an amino acid sequence as shown in any one of SEQ ID NOs: 14, 31.
4 . The isolated antigen-binding protein according to claim 2 , wherein the L-FR3 is located between the LCDR2 and the LCDR3, and the L-FR3 comprises an amino acid sequence as shown in any one of SEQ ID NOs: 15, 32.
5 . The isolated antigen-binding protein according to claim 2 , wherein an N-terminus of the L-FR4 is linked to a C-terminus of the LCDR3, and the L-FR4 comprises an amino acid sequence as shown in any one of SEQ ID NOs: 16, 33.
6 . The isolated antigen-binding protein according to claim 1 , wherein the VL comprises an amino acid sequence as shown in any one of SEQ ID NOs: 9, 20-22.
7 . The isolated antigen-binding protein according to claim 1 , comprising an antibody light chain constant region, and the antibody light chain constant region comprises a human Igκ constant region.
8 . The isolated antigen-binding protein according to claim 1 , comprising an antibody light chain LC, and the LC comprises an amino acid sequence as shown in any one of SEQ ID NOs: 64, 46-48.
9 . The isolated antigen-binding protein according to claim 1 , wherein the VH comprises framework regions H-FR1, H-FR2, H-FR3, and H-FR4, a C-terminus of the H-FR1 is directly or indirectly linked to an N-terminus of the HCDR1, and wherein the H-FR1 comprises an amino acid sequence as shown in any one of SEQ ID NOs: 5, 25, 29.
10 . The isolated antigen-binding protein according to claim 9 , wherein the H-FR2 is located between the HCDR1 and the HCDR2, and the H-FR2 comprises an amino acid sequence as shown in any one of SEQ ID NOs: 6, 26.
11 . The isolated antigen-binding protein according to claim 9 , wherein the H-FR3 is located between the HCDR2 and the HCDR3, and the H-FR3 comprises an amino acid sequence as shown in any one of SEQ ID NOs: 7, 27.
12 . The isolated antigen-binding protein according to claim 9 , wherein an N-terminus of the H-FR4 is linked to a C-terminus of the HCDR3, and the H-FR4 comprises an amino acid sequence as shown in any one of SEQ ID NOs: 8, 28.
13 . The isolated antigen-binding protein according to claim 1 , wherein the VH comprises an amino acid sequence as shown in any one of SEQ ID NOs: 1, 17-19.
14 . The isolated antigen-binding protein according to claim 1 , comprising an antibody heavy chain constant region, and the antibody heavy chain constant region is derived from a human IgG1 heavy chain constant region.
15 . The isolated antigen-binding protein according to claim 1 , comprising an antibody heavy chain HC, and the HC comprises an amino acid sequence as shown in any one of SEQ ID NOs: 63, 43-45.
16 . A pharmaceutical composition, comprising the isolated antigen-binding protein according to claim 1 , as well as optionally a pharmaceutically acceptable adjuvant.
17 . A method for activating GITR, comprising administering the isolated antigen-binding protein according to claim 1 .