CN117442718A

CN117442718A - anti-PD-1 antibodies and their use in the preparation of a medicament for the treatment of colon cancer patients

Info

Publication number: CN117442718A
Application number: CN202310583674.8A
Authority: CN
Inventors: 白莉惠; 朱吉满
Original assignee: Guangzhou Yuheng Biotechnology Co ltd
Current assignee: Guangzhou Yuheng Biotechnology Co ltd
Priority date: 2022-12-28
Filing date: 2023-05-23
Publication date: 2024-01-26
Also published as: CN116036266A

Abstract

The present invention relates to the use of an anti-PD-1 antibody or antigen-binding fragment thereof in the treatment of colon cancer. Provides a new way for treating colon cancer.

Description

anti-PD-1 antibodies and their use in the preparation of a medicament for the treatment of colon cancer patients

Technical Field

The invention belongs to the field of antibodies, and particularly relates to an anti-PD-1 antibody and application thereof in preparing medicines for treating colon cancer patients.

Background

Colon cancer is a common malignancy of the digestive tract occurring in the colon, and has a great correlation with red meat (such as beef) eaten by people. The disease is best generated at the junction of rectum and sigmoid colon, the incidence rate is highest in the age group of 40-50 years old, and the ratio of men to women is 2-3: 1. the incidence rate accounts for the 3 rd position of gastrointestinal tumor. Colon cancer is mainly adenocarcinoma, mucinous adenocarcinoma, and undifferentiated carcinoma. The general form is polypoid, ulcer, etc. Colon cancer can develop along the circulation of intestinal wall, up and down along the longitudinal diameter of intestinal canal or deeply infiltrate into intestinal wall, and can be planted in abdominal cavity or spread and transferred along suture line and incision surface besides lymphatic vessel, blood flow transfer and local invasion. Patients with chronic colitis, colon polyp, male obesity, etc. are susceptible people.

At present, the colon cancer adopts a comprehensive treatment mode taking surgical treatment as a main treatment and chemotherapy and radiotherapy as auxiliary treatment. However, the quality of life of the patient is severely affected by a variety of adverse effects such as gastrointestinal disorders, focal metastases, recurrence, infection, and hair loss, etc. caused by these treatments.

Since colon cancer has no specific symptoms in early stage, more than half of patients already belong to middle and late stages in clinical diagnosis, the current treatment is mainly performed by surgery and chemotherapy, but a large part of patients who receive auxiliary chemotherapy after colon cancer surgery still die due to recurrence and metastasis. The understanding of pathogenesis of colon cancer and diagnostic treatment methods is far from comprehensive and careful. Along with the development of medicine, along with the continuous and deep research of tumor immunotherapy, the subjects of immunology, molecular biology and the like develop continuously in recent 10 years, and especially the development of monoclonal antibodies aiming at cell immunity key regulation targets PD-1/PD-L1, CTLA-4, LAG-3 and the like for scientifically elucidating tumor immunity escape and immune tolerance occurrence mechanisms, the monoclonal antibodies make breakthrough progress, and thus the monoclonal antibodies become one of the most important methods in the current tumor immunotherapy, and have great research value and development potential.

Disclosure of Invention

In order to overcome the problems in the background art, the invention provides an anti-PD-1 antibody and application thereof in preparing medicines for treating colon cancer patients.

In order to achieve the above purpose, the invention is realized by the following technical scheme:

use of an anti-PD-1 antibody or antigen-binding fragment thereof in the manufacture of a medicament for treating a patient with colon cancer, wherein the antibody or antigen-binding fragment thereof comprises:

a heavy chain variable region comprising CDR1 shown in SEQ ID NO. 1, CDR2 shown in SEQ ID NO. 2 and CDR3 shown in SEQ ID NO. 3; and a light chain variable region comprising CDR1 shown in SEQ ID NO. 4, CDR2 shown in SEQ ID NO. 5 and CDR3 shown in SEQ ID NO. 6.

Further, the antibody or antigen binding fragment thereof is a fully human monoclonal antibody.

Further, the antibody or antigen binding fragment thereof, wherein the fully human monoclonal antibody is produced by a transgenic rat.

Further, the antibody or antigen binding fragment thereof, which blocks binding of human PD-1 to its ligand, and thus provides at least one of the following activities:

a) In CD4 ⁺ Induction of IL-2 production in T cells;

b) In CD4 ⁺ Induction of ifnγ production in T cells;

c) Induction of CD4 ⁺ Proliferation of T cells; and

d) Reversing the T-reg inhibition function.

Further, the antibody or antigen binding fragment thereof is a bifunctional antibody (diabody), scFv dimer, dsFv, (dsFv) 2, dsFv-dsFv ', fv fragment, fab ', or F (ab ') 2.

Further, the antibody or antigen binding fragment thereof, the bifunctional antibody is BsFv or ds bifunctional antibody (ds diabody).

Further, the antibody or antigen binding fragment thereof further comprises an immunoglobulin constant region.

Further, the antibody or antigen binding fragment thereof further comprises a conjugate.

The invention has the beneficial effects that: the invention provides an anti-PD-1 antibody and a new approach for treating colon cancer.

Drawings

FIG. 1 is a graph showing the change in body weight of hPD-1KIMC38 tumor-bearing mice in the present invention in treatment with a test agent and a control agent;

FIG. 2 is a graph showing the change in tumor volume in the treatment of a hPD-1KIMC38 tumor-bearing mouse test agent and a control agent according to the invention.

Detailed Description

In order to make the objects, technical solutions and advantageous effects of the present invention more apparent, preferred embodiments of the present invention will be described in detail below to facilitate understanding by the skilled person.

Example 1: antibody hybridoma production

1.1 production of immunogens

Full length DNA encoding the ECDs of PD-1 and PD-L1 or both was synthesized and inserted into expression vector pcDNA3.3. Plasmid DNA was prepared in large quantities and the inserted DNA sequence was verified by sequencing. Fusion proteins of PD-1ECD and PD-L1ECD, prepared by transfection of the human PD-1ECD gene into CHO-S or HEK293 cells, contain a variety of tags, including human Fc, mouse Fc and His tags. After 5 days, the supernatant harvested from the transiently transfected cell culture was used for protein purification. The fusion proteins were purified and quantified for immunization and screening.

1.2 establishment of stable cell lines

To obtain tools for antibody screening and validation, PD-1 and PD-L1-transfected cell lines were established. Briefly, pCND3.3 expression vectors containing full length PD-1 or PD-L1 were transfected into CHO-K1, 293F or Ba/F3 cells using Lipofectamine 2000 transfection kit according to the manufacturer's instructions. 48-72 hours after transfection, the transfected cells are cultured in medium containing Blasticidin (Blasticidin) or G418 for selection. After a period of time, cells stably incorporating the PD-1 or PD-L1 gene in genomic DNA are selected. At the same time, it was verified whether the cells had the expression of the genes of interest PD-1 and PD-L1. Once the expression was verified, individual clones of interest were picked by limiting dilution and amplified to large capacity. The established monoclonal cell line is then maintained in medium containing the low dose antibiotic Blasticidin (Blasticidin) or G418.

1.3 establishment of antibody hybridomas

1.3.1 immunization and cell fusion: human PD-1ECD protein in 10 μg TiterMax was used in 8-1 0 week old O M T-rats (obtained from O pe n M O n O c l O na lTechnology, inc., palo Alto, US)Primary challenge was performed on the footpad and immunization was repeated every 3 days with PD-1ECD formulated with aluminum. Rats were bled every 2 weeks and serum was collected and antibody titers were determined by ELISA or FACS tests. When the antibody titer reached high enough, the final adjuvant-free challenge (100 μl 1XPBS substitution) was given to the rats and cell fusion was performed as follows: b lymphocytes isolated from lymph nodes of immunized OMT-rats were cell fused with myeloma cells (at a 1:1 ratio). The cell mixture was washed and suspended with 5-10ml of ECF solution. The ECF solution was added to adjust the concentration to 2X10 ⁶ Cells/ml. Immediately after cell electrofusion, the cell suspension in the fusion chamber was transferred into a sterile tube containing more volume of medium. After incubation at 37 ℃ for more than 24 hours, the cell suspension was mixed and pipetted into a 96-well plate (0.5x10) ⁶ Cell/plate). The cells were cultured at 37℃under 5% CO2. When the clones were large enough, 100 μl of supernatant was transferred from the 96-well plate for antibody screening test.

1.3.2 first round and confirmation screening of hybridoma supernatants: ELISA assays were used as the first round of screening to test binding of hybridoma supernatants to PD-1 proteins. Briefly, plates were coated overnight at 4℃with 1. Mu.g/ml of soluble protein of the extracellular domain of human PD-1. After blocking and washing, the hybridoma supernatants were transferred to the coated plates and incubated for 1 hour at room temperature. The plates were then washed and then incubated with goat anti-rat IgG1HRP (Bethyl) and goat anti-rat IgG2b HRP (Bethyl) secondary antibodies for 45 minutes. After washing, TMB substrate was added and the reaction was quenched with 2M HCl. The absorbance at 450nm was read using a microplate reader (Molecular Device). To confirm the natural binding of PD-1 antibodies to conformational PD-1 molecules expressed on the cell membrane, FACS analysis was performed on PD-1 transfected CHO-S cell lines. At 1x10 ⁶ Cell/ml concentration CHO-S cells expressing PD-1 were transferred to 96-well U-bottom plates (BD). The hybridoma supernatants were then transferred to the plates and incubated for 1 hour at 4 ℃. After washing with 1XPBS/1% BSA, goat anti-rat FITC (Jackson Immunoresearch Lab) secondary antibody was added and incubated with cells at 4℃for 1 hour in the dark. The cells were then washed and in 1XPBS/1% BSAThe cells were resuspended or fixed in 4% formalin and analyzed by flow cytometry (BD). Binding of antibodies to maternal CHO-S cell lines was performed using the same method.

1.3.3 subcloning of hybridomas: once specific binding and blocking is verified by the first round and confirmation of screening, subcloning can be performed using the positive hybridoma cell line. Briefly, for each hybridoma cell line, cells were counted and diluted to 5 cells/well, 1 cell/well, and 0.5 cells/well in cloning medium. 200 μl/well was plated into 96-well plates, one plate at 5 cells/well, one plate at 1 cell/well and four plates at 0.5 cells/well. All plates were placed at 37℃with 5% CO2. Incubate until all cell lines can be checked by ELISA test.

Example 2: antibody hybridoma cell sequencing and fully human antibody characterization

2.1 antibody hybridoma cell sequencing: RNA was isolated from monoclonal hybridoma cells using Trizol reagent. VH and VL of PD-1 antibodies were amplified using the following protocol: briefly, first RNA was reverse transcribed into cDNA using reverse transcriptase as described herein, reaction system (20 μl):

mu.l of the PCR reaction product was taken and subjected to ligation with the pMD18-T vector. Top10 competent cells were transformed with 10. Mu.l ligation product and the mixture was transferred to 2-YT+cab plates pre-warmed according to standard protocols and incubated overnight. Positive clones were checked by PCR using M13-48 and M13-47 primers, followed by sequencing.

2.2 construction of fully human antibody molecules: VH and VL of PD-1 antibodies were amplified as described above. The PCR reaction products were purified by PCR clean-up kit and VL and pCI vectors were digested with restriction enzymes Pme I and BssH II at 37℃for 2 hours. The reaction products were electrophoresed in a 1% agarose gel and gel extracted according to manufacturer's instructions. The digested VL and pCI vectors were ligated using the following procedure:

the mixture was incubated at 16℃for 30 minutes. Transformation and clonal expansion were performed with 10. Mu.l of reaction product. Plasmid pCI-VL DNA was extracted using the confirmed clone. The pCI-VL vector and VH fragment were then digested with Xbal and Sal I and purified digested VH and vector were ligated using T4DNA ligase at 16℃for 30 min. Once the sequence of the inserted VL and VH was verified by sequencing, transient transfection and establishment of stable cell lines were performed using expression vectors containing whole IgG of fully human PD-1 antibodies.

Example 3: characterization of fully human antibodies

3.1 full kinetic binding affinity of Surface Plasmon Resonance (SPR) assay: the affinity and binding kinetics of antibodies to PD-1 were characterized by the SPR method using Proteon XPR36 (Bio-Rad). Protein A protein (Sigma) was immobilized on a GLM sensor chip (Bio-Rad) by amine coupling. Purified antibodies were flowed through the sensor chip and captured by protein a. The chip was rotated 90℃and washed with running buffer (1 XPBS/0.01% Tween20, bio-Rad) until baseline stabilized. 5 concentrations of human PD-1 and running buffer were flowed through the antibody flow cell at a flow rate of 100. Mu.L/min, followed by a combined phase flow of 240s and then a dissociated phase of 600s. The chips were regenerated after each run with H3PO4 at pH 1.7. Binding and dissociation curves were fitted to a 1:1 Langmiur binding model using ProteOn software.

3.2 binding affinity of PD-1 antibodies to cell surface PD-1 molecules as determined by flow cytometry (FACS): the binding affinity of the antibodies to cell surface PD-1 was tested by FACS analysis. At 5x10 ⁵ Cell/ml concentration CHO-S cells expressing PD-1 were transferred to 96-well U-bottom plates (BD). The antibodies to be tested were serially diluted 1:2 (1 XPBS/1% BSA) with wash buffer and incubated for 1 hour at 4 ℃. Secondary anti-goat anti-human IgG Fc FITC (3.0 moles FITC per mole IgG, (Jackson Immunoresearch Lab)) was added and incubated at 4℃for 1 hour in the dark. Cells were then washed once and resuspended in 1XPBS/1% BSA and analyzed using flow cytometry (BD). Based on the quantified beads (QuantumTM MESF Kit (Bangs Laboratories, inc.)), the fluorescence intensity was converted into a bound molecule on each cell. KD was calculated using Graphpad Prism 5.

3.3 effects of human PD-1 antibodies on T cell proliferation. The effect of PD-1 antibodies on T lymphocyte proliferation was tested using an allogeneic response. In 96 well U-bottom tissue culture plates in 200 μl RPMI 1640 containing 10% FCS and antibioticsPrimary Dendritic Cells (DC) -stimulated MLR. DC was combined with 1X10 ⁵ Allogeneic total CD4 of (C) ⁺ T cells were mixed in a ratio of 1:10 and 1:100 DC to T cells. Culturing in the presence or absence of neutralizing mAb: the human PD-1 antibody and reference antibodies A and B were used at a concentration of 10. Mu.g/ml. Incubation test for 5 days, 1 uCi/well added during the last 16 hours [ ³ H]Thymidine. Determination by scintillation counting [ ³ H]Thymidine incorporation, with three-well averaging [ ³ H]Thymidine incorporation (counts per minute) indicates a proliferative response. DC only counts were conventionally<1000cpm. The results shown are representative examples of a minimum of 5 trials performed.

Human Dendritic Cells (DC) and CD4 for use in the above allogeneic MLR ⁺ T、CD8 ⁺ T and total cells were generated from PBMCs as follows: human monocytes were purified from PBMCs by negative selection using human monocyte concentration kit (human monocyte enrichment cocktail kit) according to the instructions of the manufacturer (StemCell menu). Briefly, PBMC were isolated from healthy donor blood using Ficoll-Paque gradient. Cells were washed twice with PBS, then 1X10 in separation buffer ⁸ Cells/ml were resuspended and the Ab mixture was incubated with monocyte concentration for 30 min at 4 ℃. Unlabeled monocytes passed through MACS column were collected. To generate iDC, monocytes are cultured with GM-CSF (PeproTech, rocky Hill, NJ; 800U/ml) and IL-4 (PeproTech; 500U/ml) at a cell concentration of 2X10 in a medium of RPMI 1640 containing 10% FCS and antibiotics ⁶ Cells/ml. Half of the medium was replaced daily with medium containing GM-CSF and IL-4. The iDC was stimulated with LPS (026:B6; sigma-Aldrich, st. Louis, MO; 1. Mu.g/ml) for an additional 24 hours on day 5 to generate mature DCs. By combining PBMC with human CD4 according to the manufacturer's instructions (Stemsep) ⁺ T、CD8 ⁺ Negative selection of T and Total T cell concentrate mixtures and magnetic colloid incubation for purification of CD4 ⁺ T、CD8 ⁺ T and total T cells.

Stimulation of human CD4 with allogeneic DCs in the presence or absence of PD-1 antibodies 1.7.3hAb, 1.49.9hAb, 1.103.11hAb, 1.139.15hAb and 1.153.7hAb ⁺ T cells. Warp [ warp ] ³ H]Thymidine incorporationAssessment of CD4 ⁺ Proliferation of T cells. 1.7.3hAb, 1.49.9hAb, 1.103.11hAb, 1.139.15hAb and 1.153.7hAb increased concentration-dependent T cell proliferation.

3.4 effects of in vitro human PD-1 antibodies on cytokine IFNγ secretion: to evaluate the blocking effect of human PD-1 antibodies on the production of the cytokine IFNγ, we performed experiments on the production of IFNγ in allogeneic-MLR. Briefly, CD4 was used according to the manufacturer's instructions ⁺ T cell concentration kit (CD 4) ⁺ T cell enrichment cocktail kit) negative selection of human CD4 ⁺ T cells were purified from PBMCs. Immature DCs were generated in monocytes cultured for 5 days in GM-CSF and IL-4 and differentiated to mature DCs by overnight stimulation with LPS at 1 μg/ml. CD4 ⁺ T cells and iDC/mDC were mixed in a T:1 and 100:1 ratio of T to DC. The culture is performed in the presence or absence of the human PD-1 antibody and the reference antibody. After 5 days, the supernatant of each culture was collected and assayed for cytokine ifnγ. Ifnγ levels in the supernatant were determined by ELISA test. Briefly, maxisorp plates (0.75. Mu.g/ml; i.e., 1/1360) were coated with anti-human IFNγ mAb diluted in coating buffer, 50. Mu.l/well (i.e., 3.7. Mu.l antibody was added to 5ml coating buffer to a full 96 well plate) and incubated overnight at 4 ℃. Blocking buffer 200 μl/well was added for 2 hours to block excess protein binding capacity. Recombinant IFNγ dilutions were prepared as standard solutions and double dilutions were made from 8000pg/ml to 125pg/ml with complete medium, plus the case with complete medium only. The plates were washed, added with standard solution and test supernatant (100. Mu.l/well), and incubated for 2-4 hours. Biotinylated anti-IFNγ mAb (1/1333) in blocking buffer was added followed by additional avidin peroxidase. The reaction was performed by adding TMB substrate and quenched with 2M HCl. Absorbance was measured at 450 nm.

The results show that human CD4 was stimulated with allogeneic DCs in the presence or absence of the 1.7.3hAb, 1.49.9hAb, 1.103.11hAb, 1.139.15hAb and 1.153.7hAb antibodies ⁺ T cells. Ifnγ levels were determined by ELISA. The results showed that fully human PD-1 antibodies increased ifnγ secretion in a dose dependent manner.

3.5In vitro Effect of human PD-1 on Interleukin 2 (IL-2) production: CD4 ⁺ T cells and iDC/mDC were mixed in a T:1 and 100:1 ratio of T to DC. The culture is performed in the presence or absence of the human PD-1 antibody and the reference antibody. After 5 days, the supernatant from each culture was collected and assayed for cytokines. IL-2 levels in supernatants were determined by ELISA testing.

The results show stimulation of human CD4 with allogeneic DCs in the presence or absence of the antibodies of the present application or control antibodies ⁺ T cells. IL-2 levels were determined by ELISA. The results showed that fully human PD-1 antibodies increased ifnγ secretion in a dose dependent manner. The results show that anti-PD-1 antibodies increase IL-2 secretion in a dose dependent manner.

3.6 Effect of human PD-1 antibodies on cell proliferation and cytokine production by autoantigen-specific immune responses: in this assay, T cells and DC cells are from the same donor. Briefly, CD4 purification from PBMC ⁺ T cells were cultured in CMV pp65 peptide and low dose of IL-2 (20U/ml) while DC were generated from monocytes cultured in PBMC of the same donor in GM-CSF and IL-4. After 5 days, CD4 to be treated with CMV pp65 peptide was used ⁺ T cells were co-cultured with DCs pulsed with pp65 peptide in the presence or absence of human PD-1 antibody and reference antibody (as controls).

On day 5, 100. Mu.l of supernatant from each culture was used to determine the cytokines IFNγ and IL-2. Levels of ifnγ and IL-2 production were detected by ELISA assays. Specific T cell proliferation passage against pulsed addition of CMV pp65 peptide DC [ ³ H]And (3) measuring the incorporation of the thymidine.

The results show that PD-1 antibodies increased concentration-dependent CMV stimulated by autologous DCs loaded with CMV pp65 peptide ⁺ -CD4 ⁺ Proliferation of T cells.

3.7 Effect of human PD-1 antibodies on regulatory T-cell (Tregs) inhibition function: tregs are a subset of T cells that are critical immunomodulators, playing a critical role in maintaining self tolerance.

CD4 ⁺ CD25 ⁺ Regulatory T cells and tumor phasesIn this regard, because increased numbers of Tregs are found in a variety of cancer patients, and are associated with a poor prognosis. To directly assess the effect of human PD-1 antibodies on the immunosuppressive response, we performed Tregs experiments. CD4 was isolated using specific anti-CD 25 microbeads (Miltenyi Biotec, auburn, calif.) and positive or negative selection, respectively ⁺ CD25 ⁺ And CD4 ⁺ CD25 ^- T cells. Initially, PBMCs were incubated with human cd4+ T cell concentrate mixtures and magnetic colloids according to manufacturer's instructions (Stemsep) for purification of CD4 by negative selection ⁺ T cells. Thereafter, CD4 was resuspended in MACS buffer ⁺ T cells, on ice and CD25 ⁺ The beads were incubated for 30 minutes, washed and loaded onto a column. Collecting CD4 from the effluent solution that does not bind to the column ⁺ CD25 ^- T cells and washed prior to use. Subsequent recovery of CD4 from the column ⁺ CD25 ⁺ T cells were washed prior to use. Tregs are combined with CD4 in the presence or absence of a 10. Mu.g/ml concentration of a human PD-1 antibody ⁺ CD25 ^- T cells and DCs (Treg: teff ratio 1:1) were cultured. No antibody or isotype antibody was used as negative control. Supernatants from the cultures were taken on day 5 for ELISA to detect cytokines by addition at 1 uCi/well concentration [ ³ H]Thymidine and further incubation for 18 hours was used to detect cell proliferation. [ ³ H]Thymidine incorporation was by scintillation counting. The results showed that the PD-1 antibody removed Treg inhibitory function and restored responsive T cell proliferation and ifnγ secretion.

3.8ADCC/CDC assay: to make healthy PD-1 ⁺ Unwanted cytotoxicity was minimized and selected anti-PD-1 fully human antibodies were confirmed to be free of ADCC and CDC functions.

3.9ADCC: activated T cells expressing high levels of cell surface PD-1 were used as target cells and pre-incubated with different concentrations of fully human antibodies in 96-well plates for 30 min followed by addition of IL-2 activated PBMCs (used as Natural Killer (NK) cell sources, i.e. effector cells) at 50:1 effector/target cell ratio. The plates were incubated at 37℃in a 5% CO2 incubator for 6 hours. Target cell lysis was determined by cytotoxicity detection kit (Roche). The optical density was determined by a Molecular Devices SpectraMax M e microplate reader. The results show that the fully human anti-PD-1 antibodies tested did not mediate ADCC.

CDC: target cells (activated T cells), diluted human serum complement (Quidel-A112) and different concentrations of fully human PD-1 antibodies were mixed in 96-well plates. The plates were incubated for 4 hours at 37℃in a 5% CO2 incubator. Target cell lysis was determined by CellTiter glo (Promega-G7573). Rituxan (Roche) and human B lymphocyte fine Raji (CD 20 positive) served as positive controls. The data shows that the PD-1 antibodies do not mediate CDC.

Example 4: medicine curative effect research of anti-PD-1 antibody injection in hPD KI mouse colon cancer MC38 model

The purpose is as follows: preclinical validation of efficacy of treatment of mice colon cancer MC38 tumor model with anti-PD-1 antibody injection in hPD-1KI mice.

The method comprises the following steps: using hPD-1KI mice, the right side of the mice tested were inoculated subcutaneously with MC38 tumor cells (1X 10 ⁶ /alone), a tumor model is established. The average tumor volume reaches 150mm ³ Random time groups (Isotype control, GLS-010 injections low and high concentration group, kettuda group, 8 each), dosing (BIW. Times.3, i.p.). Tumor diameters were measured 2 times per week with vernier calipers. The calculation formula of the tumor volume is: v=0.5a×b ² A and b represent the major and minor diameters of the tumor, respectively. The tumor inhibiting effect was evaluated by T-C (day), T/C (%) and TGI (%).

Results:

1) Animal body weight: the mice in each group had a smooth body weight without significant weight loss, see figure 1.

2) Tumor volume: the tumor volume of the test drug group was significantly reduced, as shown in FIG. 2 and Table 1.

TABLE 1 anti-PD-1 antibodies tumor inhibiting Effect in hPD-1KI MC38 tumor bearing mice

Annotation: a. data are expressed as "mean ± standard error";

b. TGI, T/C results and P values based on day 10 data are shown in parenthesis;

c. performing a significant difference analysis between tumor volumes of each treatment group by using a one-way ANOVA (one-way ANOVA) method; groups 2-3 were statistically significantly different (P < 0.05) from group 1, and there was no significant difference (P > 0.05) between groups 2-4.

Conclusion: anti-PD-1 antibody injection (10 mg/kg and 20 mg/kg) showed statistically significant anti-tumor effect in the hPD-1KI mouse MC38 tumor model; the lower and equivalent doses of anti-PD-1 antibodies were not statistically significantly different from the positive control Keytruda.

Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

1. Use of an anti-PD-1 antibody or antigen-binding fragment thereof in the manufacture of a medicament for treating a patient with colon cancer, wherein the antibody or antigen-binding fragment thereof comprises:

2. The use of claim 1, wherein the antibody or antigen-binding fragment thereof is a fully human monoclonal antibody.

3. The use of claim 1, the antibody or antigen binding fragment thereof, wherein the fully human monoclonal antibody is produced by a transgenic rat.

4. The use according to claim 1, said antibody or antigen binding fragment thereof, which blocks binding of human PD-1 to its ligand and thus provides at least one of the following activities:

a) Induction of IL-2 production in cd4+ T cells;

b) Induction of ifnγ production in cd4+ T cells;

c) Inducing proliferation of cd4+ T cells; and

d) Reversing Treg inhibition function.

5. The use of claim 1, wherein the antibody or antigen binding fragment thereof is a bifunctional antibody (diabody), scFv dimer, dsFv, (dsFv) 2, dsFv-dsFv ', fv fragment, fab ', or F (ab ') 2.

6. The use of claim 1, wherein the antibody or antigen binding fragment thereof, the bifunctional antibody is BsFv or ds bifunctional antibody (dsdiabody).

7. The use of claim 1, wherein the antibody or antigen-binding fragment thereof further comprises an immunoglobulin constant region.

8. The use of claim 1, wherein the antibody or antigen-binding fragment thereof further comprises a conjugate.