CN118561966B

CN118561966B - Human endogenous retrovirus envelope protein mutants, truncated forms and uses thereof

Info

Publication number: CN118561966B
Application number: CN202410621371.5A
Authority: CN
Inventors: 徐荣臻; 李梦圆
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2024-05-20
Filing date: 2024-05-20
Publication date: 2025-07-11
Anticipated expiration: 2044-05-20
Also published as: CN118561966A

Abstract

The present invention belongs to the field of biotechnology, and specifically relates to human endogenous retrovirus envelope protein mutants, truncations and their uses. The envelope protein mutants and truncations designed by the inventors based on HERVs can induce the immune system to produce a strong immune response, which can not only be used for various therapeutic and preventive vaccines such as mRNA vaccines, protein subunit vaccines, polypeptide vaccines, etc., the design of therapeutic and diagnostic antibodies, the design of specific therapeutic cell products, such as CAR-T cells, specific cytotoxic T cells, CAR-NK cells, specific NK cells, etc., for the diagnosis, prevention and treatment of diseases.

Description

Human endogenous retrovirus envelope protein mutant, truncated body and application thereof

Technical Field

The invention belongs to the technical field of biology, and particularly relates to a human endogenous retrovirus envelope protein mutant, a truncated body and application thereof.

Background

Human Endogenous Retroviruses (HERVs) are residues of retroviruses that infect humans several hundred years ago and integrate into the human genome, inheriting in a Mendelian manner to date, accounting for about 8% of the human genome. Among them, most HERVs have lost their encoding ability due to mutation, deletion, and the presence of a termination code in the encoding sequence, and have been conventionally considered as garbage DNA. However, as the biological functions of HERVs are studied intensively in recent years, it is found that some HERVs have important physiological functions in specific tissues and organs, and are possibly closely related to the occurrence and development of blood and solid tumors, autoimmune diseases, neurodegenerative diseases and the like. It is known that the C-terminal transmembrane region (TM) of the envelope protein (envelope, env) of HERVs has multiple immunosuppressive domains, such as Fusion Peptide (FP), immunosuppressive region (Immunosuppressive Domains, ISD), transmembrane region (Transmembrane Domain, TMD), has a powerful immunosuppressive function, and is an important cause of tumor immune tolerance. The N-terminus of envelope protein (SU) is involved in a variety of inflammatory responses.

Therefore, research on whether the HERVs envelope protein has important physiological functions available and modified for human beings, so that application of the HERVs envelope protein to diagnosis, prevention and treatment of diseases is a pain point and a hot spot of current industry research.

Disclosure of Invention

The invention relates to envelope protein mutants and truncations of HERV-K, HERV-H and HERV-F, and the use thereof in the preparation of medicaments for disease diagnosis and/or treatment, wherein the mutation sites of the envelope protein mutants and the truncations of the truncations are conserved regions which are not influenced by different subtypes (HERV-K, HERV-H and HERV-F).

A mutant or truncate of the envelope protein of a human endogenous retrovirus, said mutant or truncate being mutated at a single or multiple amino acids in the immunosuppressive domain.

Preferably, the immunosuppressive domain is an immunosuppressive region.

Preferably, the human endogenous retrovirus is any one of HERV-K, HERV-H or HERV-F.

Preferably, HERV-K is any one of HERV-K108 or HERV-K102, and the amino acid sequence corresponding to each human endogenous retrovirus typing is as follows:

The sequence of HERV-K108 envelope protein mutant is shown as SEQ ID NO. 1,

The sequence of HERV-K108 envelope protein truncated body is shown in SEQ ID NO. 5,

The sequence of HERV-K102 envelope protein mutant is shown in SEQ ID NO. 3,

The sequence of HERV-K102 envelope protein truncated body is shown in SEQ ID NO. 7,

The sequence of HERV-F envelope protein mutant is shown in SEQ ID NO. 9,

The sequence of HERV-F envelope protein truncated body is shown as SEQ ID NO. 11,

The sequence of HERV-H envelope protein mutant is shown as SEQ ID NO. 13,

The sequence of HERV-H envelope protein truncated body is shown in SEQ ID NO. 15.

Preferably, the mutant or the truncated body is a transmembrane protein formed by hydrolyzing an envelope protein of a human endogenous retrovirus by furin, and the corresponding amino acid sequence is as follows:

The sequence of HERV-K108 transmembrane protein mutant is shown as SEQ ID NO. 2,

The sequence of HERV-K108 transmembrane protein truncated body is shown in SEQ ID NO. 6,

The HERV-K102 transmembrane protein mutant has a sequence shown in SEQ ID NO. 4,

The sequence of HERV-K102 transmembrane protein truncated body is shown in SEQ ID NO. 8,

The HERV-F transmembrane protein mutant has a sequence shown in SEQ ID NO. 10,

The sequence of HERV-F transmembrane protein truncated body is shown in SEQ ID NO. 12,

The HERV-H transmembrane protein mutant has a sequence shown in SEQ ID NO. 14,

The sequence of HERV-H transmembrane protein truncated body is shown in SEQ ID NO. 16.

Use of a mutant or a truncate of an envelope protein, including a mutant or a truncate of an envelope protein of a human endogenous retrovirus as described in any of the preceding paragraphs, in the manufacture of a medicament for use in the diagnosis and/or treatment of an immune system induced to produce a robust immune response.

Preferably, the diagnostic and/or therapeutic drug inducing the immune system to generate a strong immune response is any one of mRNA vaccine, protein subunit vaccine, recombinant gene vaccine, animal-derived antibody and envelope protein specific cell.

Preferably, the recombinant gene vaccine is any one of a plasmid vector vaccine, a viral vector vaccine or a live cell vector vaccine.

Preferably, the animal-derived antibody is any one of a mouse, rat, rabbit or alpaca-derived antibody.

Preferably, the alpaca-derived antibody is alpaca nanobody.

Preferably, the envelope protein specific cell is any one of cytotoxic T cell, NK cell, plasma cell and B cell.

Preferably, the cytotoxic T cell is any one of cd8+ and cd4+.

Use of an antibody prepared from an envelope protein mutant or a truncated antigen according to any of the preceding claims for the preparation of a specific cellular drug.

Preferably, the specific cell medicament is any one of CAR-T, CAR-NK or CAR-VAC cell medicament.

The beneficial effects of the invention are mainly as follows:

The envelope protein mutant and the truncated body designed based on HERVs can induce an immune system to generate a strong immune response, can be used for designing various therapeutic and preventive vaccines such as mRNA vaccines, protein subunit vaccines, polypeptide vaccines and the like, designing antibodies for therapeutic and diagnosis, designing specific therapeutic cell products such as CAR-T cells, specific cytotoxic T cells, CAR-NK cells, specific NK cells and the like, and is used for diagnosing, preventing and treating diseases.

Drawings

FIG. 1 is a plasmid map of a pCW-Cas9 vector;

FIG. 2 is a pcDNA3.1 (+) vector plasmid map;

FIG. 3 shows HERV-K transmembrane protein K-TM expression in different blood tumors and normal blood cells;

FIG. 4 shows HERV-W transmembrane protein W-TM expression in different blood tumor and normal blood cells;

FIG. 5 shows ERVFRD expression of the envelope protein FRD-Env in different tumors and normal blood cells;

FIG. 6 shows the effect of K-TM and W-TM on tumor cell immune escape;

FIG. 7 shows K-TM interactions with T cell CD3 molecules;

Figure 8 is the effect of HERVs envelope protein mutants, truncations and wild type on the immune response of mice.

Detailed Description

1. Noun interpretation:

human Endogenous Retroviruses (HERVs);

envelope proteins (envelope, env);

A C-terminal transmembrane region (TM) which is a transmembrane protein formed by the hydrolysis of Env by furin (furin protease);

Fusion Peptide region (FP);

an immunosuppressive region (Immunosuppressive Domains, ISD);

A transmembrane region (Transmembrane Domain, TMD);

HERV-W-Env(W-Env);

HERV-F-Env(FRD-Env);

HERV-K transmembrane protein (K-TM);

HERV-W transmembrane protein (W-TM);

Envelope protein N-terminal (SU).

2. Main instrument and equipment

3. Main reagent

4. Cell culture

Cell lines Kasumi-1,KM3,NB4,Raji,Jurkat,K562,K562/adr,KG1,MV4-11,Mia,Panc-1,Hunh7,HepG2,SW620,U2OS,L02,Nalm6,LY3,Jeko1,THP-1,HL-60,MOLM13,ARP-1,8226,MM1.S,U266,H9,A549,H1975,IMR-32,U87,HT-29 and the like used in this patent were all purchased from ATCC cell banks and stored in the university of Zhejiang tumor institute cell banks. Cells were cultured using 1640 complete medium or DMEM complete medium. In the culturing process, the cells are placed in a constant temperature incubator containing 5% CO ₂ at 37 ℃ and periodically detected, so that bacteria, fungi, mycoplasma pollution and other conditions are eliminated. According to the experimental plan and the cell state, cell liquid exchange and cell passage are carried out every 2-3 days, and the cells are maintained in the logarithmic growth phase.

5. Isolation and culture of mononuclear cells from primary sample peripheral blood

(1) Peripheral blood of the patient was withdrawn, gently shaken in EDTA anticoagulation tube to prevent blood coagulation, and placed in ice box to be brought back to laboratory. (2) The operation is carried out in an ultra clean bench, firstly, samples are moved into a clean 15mL centrifuge tube, and the samples are gently beaten and evenly mixed by a dropper. And adding an equal volume of precooled 1 XPBS buffer solution into the sample, and gently mixing and diluting. Then 2 volumes of human lymphocyte isolate were slowly added. Centrifuge at 2500rpm for 20 min, and adjust the rising speed of centrifuge 2 and falling speed 1. (3) The middle white mononuclear cell layer was aspirated and washed 1 time with pre-chilled 1 XPBS buffer. Centrifugation was carried out at 1500rpm for 5 minutes at room temperature.

(4) The supernatant was discarded, 2mL of the erythrocyte lysate was added, and after 10 minutes of lysis at room temperature, the mixture was centrifuged at 1000rpm for 5 minutes. By using

1 X PBS buffer washing 1 times.

(5) And collecting cells, adding protein lysate, and extracting total protein of primary sample PBMC cells for subsequent western blot experiments.

EXAMPLE 1 expression of HERV-K transmembrane protein K-TM in different blood tumor and Normal blood cells

The expression condition of HERV-K transmembrane protein K-TM in a blood tumor cell strain, a primary tumor cell sample, a normal blood cell sample and a bone marrow sample before treatment (UT) and after treatment relief (CR) of a leukemia patient is detected by a western blot technology.

The specific experimental steps are as follows:

(1) Cellular protein extraction and quantification

A cells were collected, centrifuged at 1000rpm for 5min, the supernatant was discarded, resuspended in 1mL of pre-chilled PBS, and transferred to 1.5mL of EP

In the tube, 1000rpm,5min, centrifuging to discard the supernatant;

b protein lysate was prepared in advance, and the preparation was performed at a ratio of 10. Mu.L of protease inhibitor cocktail and 10. Mu.L of EDTA PER 1mL of M-PER lysate. An appropriate amount of protein lysate was added to the cell pellet and lysed on ice for 30min. C after centrifugation at 13000rcf for 15min at 4℃the supernatant was aspirated into a 0.6mL centrifuge tube. mu.L was taken and protein concentration was quantified using BCA kit according to the instructions. The rest supernatant is added according to the ratio of supernatant to loading 4:1

5X Loading Buffer, mixing by vortex, heating in metal bath at 100deg.C for 10min, and placing on ice or storing in refrigerator at-80deg.C for a long time.

(2) Western blot experiment

A, preparing SDS-PAGE gel, namely preparing a separation gel with the concentration of 10% according to the molecular weight of target protein. Sequentially to 50mL

Into the centrifuge tube were added ddH ₂ O4.0 mL, 30% acrylamide 3.3mL, 1.5M Tris-HCl (pH 8.8) 2.5mL, 10% SDS 0.1mL, 10% AP 0.1mL, TEMED 0.004mL. After rapid mixing, the mixture was added to a glass plate, and 0.2mL of isopropyl alcohol was immediately added to flatten the adhesive surface. Standing at room temperature for 30min, and waiting for the separation gel to solidify completely. Washing off isopropanol, standing and airing. Meanwhile, concentrated gel was prepared and sequentially added to a 50mL centrifuge tube, ddH ₂ O1.72 mL, 30% acrylamide 0.5mL, 0.5M Tris-HCl (pH 6.8) 0.76mL, 10% SDS 0.03mL, 10% AP 0.03mL, and TEMED 0.003mL. 10mL of the mixture was added to the separating gel after mixing, and the comb was immediately inserted. Standing at room temperature for 30min

After that, the concentrated gel was completely coagulated. Stored in a 4 ℃ refrigerator for testing.

B SDS-PAGE gel electrophoresis, namely assembling electrophoresis equipment, and adding 1 Xelectrophoresis liquid prepared in advance. The comb was removed and an equal mass of protein sample was added to the lanes while 5 μl of protein pre-dye marker was applied to both sides of the lanes. When the concentrated glue is run out, the glue is concentrated,

The voltage is adjusted to 80V, and when electrophoresis is carried out to separate gel, the voltage is adjusted to 130V. And stopping electrophoresis when the bromophenol blue runs to the bottom of the separation gel.

And c, transferring the membrane, namely taking out the SDS-PAGE gel from the electrophoresis device, and soaking the SDS-PAGE gel in a transfer membrane solution. The PVDF membrane was taken out and immersed in methanol for 10s. The membrane transferring device is arranged, and the membrane transferring device sequentially comprises a membrane transferring clamp positive electrode, a foam cushion, double-layer filter paper, a PVDF membrane, gel, double-layer filter paper, the foam cushion and a membrane transferring clamp negative electrode from bottom to top, and simultaneously, bubbles between the gel and the PVDF membrane are discharged. And fixing a film transferring device, adding film transferring liquid, carrying out ice bath, and transferring films for 100min at a constant current of 250 mA.

And d, closing, namely taking out the PVDF film, and marking the front surface on the right upper corner cut. The membrane was placed in a blocking solution and blocked for 1h at room temperature. After the completion, the membrane was washed with 1 XTBE, slowly shaken on a shaking table at room temperature for 10min, and repeated 3 times.

E, primary antibody incubation, namely placing PVDF membrane into the primary antibody prepared in advance, and incubating overnight by a 4 ℃ shaking table.

F, secondary antibody incubation, namely taking out the PVDF membrane the next day, and washing the membrane with 1 XTBST for 10min for 3 times. And then placing the PVDF membrane into the prepared secondary antibody, and incubating for 1h at room temperature by a shaking table.

G, developing, namely after the secondary antibody incubation is finished, washing the membrane for 10min for 3 times. Development A was also configured at a 1:1 ratio

And (3) uniformly mixing the solution and the solution B, covering a PVDF film, and developing in a developing instrument.

EXAMPLE 2 expression of HERV-W transmembrane protein W-TM in different blood tumor and Normal blood cells

Detecting the expression condition of HERV-W transmembrane protein W-TM in a blood tumor cell strain, a leukemia primary tumor cell sample and a normal blood cell sample by using a western blot technology.

The procedure is as in example 1.

EXAMPLE 3ERVFRD expression of the envelope protein FRD-Env in different tumor and Normal blood cells

The expression condition of HERV-FRD transmembrane protein FRD-Env in different blood tumor cell strains, solid tumor cell strains, leukemia primary tumor cell samples and normal blood cell samples is detected by a western blot technology.

The procedure is as in example 1.

EXAMPLE 4 influence of HERV-K-TM and W-TM on immune escape of tumor cells

(1) Construction of pCW-K-TM-HA and pCW-W-TM-HA inducible lentivirus overexpression plasmid

The full-length K-TM amino acid sequence is derived from the transmembrane region 466-699aa of the human retroviral K family member 6Env protein (ENK-6, uniProt, Q69384), while the signal peptide (SIGNAL PEPTIDE, UNIPROT, Q69384,1-89 aa) is fused at the amino-terminus of the sequence, and the HA tag is fused at the carboxy-terminus.

The full length W-TM amino acid sequence is derived from the transmembrane region 291-538aa of the human retroviral W family member Syncytin-1 protein (ERVW-1, uniProt, Q9 UQF0), while the signal peptide (SIGNAL PEPTIDE, UNIPROT, Q9UQF0,1-20 aa) is fused at the amino-terminus and the HA tag is fused at the carboxy-terminus of the sequence.

Human codon optimization is carried out on the amino acid sequence by using OptimumGene codon optimization technology, and the obtained nucleic acid sequence is inserted between EcoRI and BamHI cleavage sites of a pCW-Cas9 vector (the plasmid map is shown in figure 1), so that plasmids pCW-K-TM-HA and pCW-W-TM-HA are constructed.

(2) Construction of K-TM, W-TM inducible over-expression stable transgenic cell line

And a, packaging the constructed pCW-K-TM-HA and pCW-W-TM-HA plasmid into virus liquid.

B re-suspending MCA205 cells with 1mL 1640 complete medium, adding to a twelve well plate, plating one day in advance

MCA205 cells adhere to the wall.

C 250. Mu.L of virus solution and 10. Mu.g/mL Polybrene were added to the plates and the cells were infected for 24h.

D, discarding the virus supernatant, transferring the cells into a culture flask after changing fresh culture medium, and adding puromycin with the working concentration of 2 mug/mL to screen positive cells.

E, when the cells reach a certain growth density, taking a small number of cells, and verifying the expression conditions of K-TM-HA and W-TM-HA by using a western blot. The other cells continue to use puromycin to continuously screen for 14day, namely MCA205-K-TM-HA is constructed,

MCA205-W-TM-HA stably transformed and overexpressed cell lines.

(3) Construction of MCA205 heterologous tumor model

Animals A BALB/c mice (females, 6 weeks old, weighing about 20 g) supplied by Shanghai Laek animal experiments were used. The experimental animals are fed in an SPF clean-grade environment of an animal experiment center of Zhejiang university, and animal experiment schemes and operation processes are approved by an ethical committee of a second hospital affiliated to the Zhejiang university medical institute.

B MCA205 cells overexpressing K-TM and W-TM proteins were induced by 2. Mu.g/mL Dox for 48h, the cells were collected, washed 1 time with PBS, and then resuspended in PBS to a cell suspension density of 5X 10 ⁶/mL.

C BALB/c mice were randomly divided into 2 groups of 5. The mice were inoculated with 0.2mL of MCA205-K-TM-HA and MCA205-W-TM-HA stable over-expressing cell lines, respectively, in the left underarm. Following tumor inoculation, groups 2 of mice were given a dose of 100mg/kg of Dox to induce K-TM and W-TM protein expression, administered 1 gastric lavage daily for 20 consecutive days.

Mice were monitored twice weekly for status and growth of subcutaneous tumors, euthanized after the end of the experiment, dissected for subcutaneous tumors, and photographed.

EXAMPLE 5HERV-K-TM interaction with T cell CD3 molecules

(1) Construction of K-TM inducible over-expressed Jurkat stable cell line

And a, packaging the constructed pCW-K-TM-HA plasmid and the pCW empty plasmid into virus liquid.

B Jurkat cells were resuspended using 1mL 1640 complete medium and added to twelve well plates.

E, when the cells reach a certain growth density, taking a small number of cells, and verifying the expression condition of K-TM-HA by using western blot. And continuously screening the other cells by using puromycin for 14day, namely constructing and obtaining the Jurkat-K-TM-OE stable over-expression cell strain.

(2) K-TM and CD3 epsilon immunofluorescence co-localization experiments

A collecting Jurkat-K-TM-OE cells, washing the cells once with 1 XPBS, and resuspending the cells with fetal bovine serum to the appropriate density.

B smeared onto a glass slide, cells were fixed with 4% paraformaldehyde and blocked with 10% rabbit antisera.

C adding CD3 epsilon primary antibody and incubating overnight at 4 ℃.

The next day, the slide was removed from the refrigerator, washed 3 times with 1 XPBS, and stained with Alexa Fluor 594 fluorescent labeled anti-mouse secondary antibody at room temperature in the dark for 1h.

E, staining the cell nucleus by DAPI, and staining for 10min at room temperature in dark. The images were taken and analyzed using a zeiss confocal laser scanning microscope for observation by photographing and using ZEN software.

EXAMPLE 6 influence of HERVs envelope protein mutants, truncations and wild type on the immune response of mice

(1) Preparation of antigen the inventors prepared full-length eukaryotic overexpression plasmids including wild-type, mutant, truncations of the H-Env envelope protein, pcDNA3.1 (+) -H-Env, pcDNA3.1 (+) -Mutant-H-Env, pcDNA3.1 (+)

-Measured-H-Env. The full length H-Env amino acid sequence is derived from 1-584aa of Env protein (ENH 1, uniProt, Q9N2K 0) which is a member of the human retrovirus H (HERV-H for short). The mutant H-Env amino acid sequence refers to the sequence of appendix No. 7-1-XUHMV, and the truncated H-Env amino acid sequence refers to the sequence of appendix No. 8-1-XUHMV. The amino acid sequence was subjected to human codon optimization using OptimumGene codon optimization technique, and the resulting nucleic acid sequence was inserted between EcoRI and BamHI cleavage sites of pcDNA3.1 (+) vector (plasmid map shown in FIG. 2), and plasmids pcDNA3.1 (+) -H-Env, pcDNA3.1 (+) -Mutant-H-Env and pcDNA3.1 (+) -were constructed

-Truncated-H-Env。

(2) Immunization and serum evaluation according to the conventional mouse immunization protocol, 6-week-old Balb/c mice were immunized with the above plasmid, respectively. Titer analysis of antibodies in mouse serum was performed by diluting OD450nm >1.0 at 1:8000, while titer >72900

(P/N > 2.1). And after the titer is qualified, performing flow verification by using stable transgenic cell lines, human tumor cell lines and the like, and finally selecting mice with good immune effect for fusion.

(3) Cell fusion, namely, according to immune serum titers and flow type experimental verification results such as western blot, and the like, after evaluation and confirmation, selecting an optimal mouse to arrange into fusion.

(4) And (3) monoclonalizing positive cells, namely after cell fusion, performing prescreening detection, replacing a culture medium to reduce detection background, performing ELISA primary screening after one week, selecting ELISA positive clones, performing subcloning by a two-step limiting dilution method, performing expansion culture on 5-10 positive clones detected by ELISA, performing flow verification by stable cell lines, human tumor cell lines and the like, performing expansion culture on the finally selected positive clones, and performing freezing storage.

(5) And (3) ascites preparation, namely, purifying the antibody, namely, performing ascites preparation on positive clones, analyzing the titer of the antibody in the ascites by adopting indirect ELISA, and simultaneously performing subtype analysis. And antibody affinity purification of ascites was performed.

(6) The specific experimental procedure for antibody titer detection by western blot technique is the same as in example 1.

Experimental results

The results of example 1 show that A, K-TM is expressed in different blood tumor cell lines and B, K-TM is expressed in different primary leukemia cells. Jurkat is a positive control, K-TM is expressed in normal blood cell samples, K562 is a positive control, and D K-TM is expressed in a bone marrow sample before (UT) and after treatment relief (CR) of a leukemia patient.

The results of example 2 show that A is the expression of W-TM in different tumor cell lines and B is the expression of W-TM and PD-L1 in different primary leukemia cells. KG1 is positive control, and C: W-TM and PD-L1 are expressed in normal blood cell samples.

The results of example 3 show that A is the expression of FRD-Env in different tumor cell lines and B is the expression of FRD-Env in different primary leukemia cells. THP1 is a positive control, and C is FRD-Env expression in normal blood cell samples. THP1 was a positive control.

The results of example 4 show that when K-TM protein-expressing MCA-205 cells were inoculated into BALB/C mice, it was seen that tumor cells grew rapidly, whereas W-TM-expressing MCA-205 cells were unable to grow in vivo in BALB/C mice.

The results of example 5 show that A: K-TM protein binds to T cell surface CD3 molecules and B: K-TM inhibits T cell activation pattern. K-TM binds to the T cell surface CD3 molecule and blocks its binding to the TCR receptor, thereby inhibiting T cell activation.

The results of example 6 show that A, 6 different types of antibodies can be produced after mice are immunized by mutant envelope protein plasmids, as shown by black arrows, B, 2 specific antibodies can be produced after mice are immunized by truncated envelope protein plasmids, as shown by black arrows, and C, only 1 specific antibody can be produced after mice are immunized by wild envelope protein plasmids, as shown by black arrows.

Results and analysis

The inventor applies Western blot technology to detect HERV-K transmembrane protein (K-TM) of a plurality of different tumor cell strains, primary tumor cell samples of leukemia patients and normal blood cell samples. As a result, it was found that most tumor cell lines and primary tumor cell samples highly expressed K-TM, whereas normal peripheral blood cell samples either expressed low or did not express K-TM (example 1, FIGS. 3A-C). Of note, some patients with K-TM-highly expressed leukemia also significantly reduced K-TM after complete remission by treatment (example 1, FIG. 3D).

HERV-W is recognized as a human endogenous retrovirus with important physiological functions during placenta development. Recently, some COVID-19 new coronavirus infected patients have reported that serious T cell function depletion phenomenon exists. These patients have abnormally high expression of HERV-W-Env (W-Env) by peripheral blood T lymphocytes, and the expression level thereof is not only significantly positively correlated with the level of the PD-1 marker of T cell depletion and the levels of inflammatory factors IL-6 and IL-10, but also closely correlated with the severity of the disease. These results suggest that abnormal activation of W-Env may be closely related to depletion of T cell function in COVID-19 patients. The inventor uses Western blot to detect the expression condition of the W-TM protein coded by HERV-W-Env gene in different tumor cell strains, primary tumor cell samples and normal blood cell samples. As a result, it was found that the W-TM protein was highly expressed in most tumor cell lines (example 2, FIG. 4A) and primary tumor cell samples (example 2, FIG. 4B), whereas normal blood cell samples were either low-expressed or not-expressed (example 2, FIG. 4C). Of note, some tumor samples highly expressing W-TM protein simultaneously expressed cell-derived immune checkpoint PD-L1 (example 2, fig. 4B). These results suggest that W-TM may be involved directly or indirectly in tumor immune escape.

HERV-F is another human endogenous retrovirus normally expressed only in placenta tissue, and the coded envelope protein sample FRD-Env (TM protein at the C end) has a remarkable immunosuppressive function. At present, little is known about the role of the samples FRD-Env and TM (F-TM) in tumors. As no antibody aiming at F-TM protein exists at present, the inventor uses Western blot to detect the expression condition of the FRD-Env protein of HERV-F samples in different tumor cell strains, primary tumor cell samples and normal blood cell samples. As a result, it was found that there were different degrees of FRD-Env expression in 21 different tumor cell lines (example 3, FIG. 5A), FRD-Env expression in 9 primary tumor cell samples from 20 leukemia patients (example 3, FIG. 5B), and FRD-Env expression in 20 healthy human blood cell samples (example 3, FIG. 5C).

To verify whether K-TM and W-TM have the effect of helping tumor cells escape immunity, the inventors constructed K-TM and W-TM high expression cells with MCA-205 mouse fibrosarcoma cells (C57 BL/6 mouse origin), respectively, and then vaccinated wild-type BALB/C mice with normal immunity, respectively, and observed the effect of these 2 endogenous retrovirus proteins on MCA-205 cell growth in BALB/C mice. For BALB/c mice, MCA-205 cells belong to heterologous cells, and when inoculated into BALB/c mice, the cells are cleared by immune cells, and the cells cannot grow in BALB/c mice. But if MCA-205 cells have immunosuppressive function protein, the cells can be grown in mice when the immune cell function of the mice is inhibited. As a result of the experiment, it was found that MCA-205 cells expressing W-TM could not grow in BALB/c mice, whereas MCA-205 cells expressing K-TM could grow rapidly in BALB/c mice (example 4, FIG. 6). These results indicate that K-TM has powerful immunosuppressive function and can endow MCA-205 tumor cell with immune escape function.

Similar to most human tumors, some tumors caused by retrovirus infection are often accompanied by T cell high-expression of cell-derived ICI such as PD1/PDL1, CTLA-4 and the like, and the phenomena of T cell immune function exhaustion and tumor immune escape, such as murine leukemia, bovine leukemia and HTLV-1 adult T cell leukemia, occur. Although the exact etiology and molecular mechanism are not well understood, viral envelope proteins Env and TM proteins are probably the most critical regulatory molecules. Retrovirus TM is a transmembrane protein formed by the hydrolysis of Env by furin (furin protease) and comprises multiple immunosuppressive domains, such as fusion peptides FP, ISD and TMD, where ISD is highly conserved across different retroviruses. Mature functional TM proteins are mainly distributed on cell membranes, have powerful immunosuppressive functions, and are powerful weapons for retroviruses to evade host immune system attacks. It is particularly noted that some endogenous retroviruses have envelope proteins and their transmembrane proteins TM comprising a plurality of domains with immunosuppressive functions. In HTLV-1gp21 and HIV-gp41 TM, FP, ISD and TMD have been shown to interfere with CD3 binding to TCR receptors, inhibiting T cell function. K-TM is known to significantly inhibit T cell growth and up-regulate immunosuppressive inflammatory factors IL-6 and IL-10. We have found that K-TM binds to the T cell CD3 molecule using co-IP and immunofluorescence co-localization experiments (example 5, FIG. 7A). These preliminary results suggest that K-TM may have a direct T cell inhibition function, whose mechanism of action may prevent CD3 activation of T cells (example 5, FIG. 7B).

In order to verify whether HERVs envelope proteins have an immunosuppression function, the inventor designs different types of envelope protein mutants and truncations, and then injects plasmids expressing the mutants, the truncations and wild type into mice through a plasmid gene immunization technology to immunize every 1 week for 3 times. And obtaining ascites to prepare an antibody after immunizing a mouse, performing titer detection on the prepared antibody by a western blot experiment, and then respectively observing and comparing immune response effects of mutants, truncations and wild plasmids on the mouse. As a result, it was found that, by three immunizations, the mutant envelope proteins and the truncated envelope proteins were immunized to produce specific antibody species and titers significantly higher than the wild-type envelope proteins. In particular, the mutant envelope proteins produced 6 different types of antibodies (example 6, FIG. 8A), the truncations produced 2 specific antibodies (example 6, FIG. 8B), whereas the wild type envelope plasmid immunized mice produced not only a few species (only 1), but also very low titers (example 6, FIG. 8C). The result shows that the envelope protein mutant and the truncate designed by the inventor can induce an immune system to generate a strong immune response, can be used for designing various therapeutic and preventive vaccines such as mRNA vaccines, protein subunit vaccines, polypeptide vaccines and the like, designing antibodies for therapeutic and diagnosis, designing specific therapeutic cell products such as CAR-T cells, specific cytotoxic T cells, CAR-NK cells, specific NK cells and the like, and is used for diagnosing, preventing and treating diseases.

Human Endogenous Retrovirus (HERVs) envelope protein mutant and truncated sequence design

The HERV-K envelope protein (Env) mutant refers to an Env mutant generated by mutating single or multiple amino acids of W535R (or other amino acids) of L522A (or other amino acids) of amino acids (L (A) A (G) NQINDLRQTVIW (R) MGD) of an Env immune suppression domain ISD conserved region of the present inventor. Preferred mutation site amino acids L522A, A523G and W535R, more preferred are the envelope protein mutant C-terminal transmembrane protein TM.

The HERV-K envelope protein truncate refers to a fusion peptide region (FP) FIFTLIAVIMGLIAVTATAAV and/or an immunosuppression region (immunosuppressive domains, ISD) of the envelope protein of the present invention

LANQINDLRQTVIWMGD and/or transmembrane region (transmembrane domain, TMD)

IGSTTIINLILILVCLFCLLL single or multiple deletion mutations, preferably the envelope protein truncations C-terminal transmembrane protein TM.

The HERV-H envelope protein mutant refers to an envelope protein mutant generated by mutating single or multiple amino acids of an envelope protein immune suppression domain ISD conserved region amino acid (L (A) Q (A) NRRGLDLLTAEK (R) GGL) L454A (or other amino acids), Q455A (or other amino acids) and K467R (or other amino acids). Preferred mutation site amino acids L454A, Q455A and K467R, more preferred is the envelope protein mutant C-terminal transmembrane protein TM.

The HERV-H envelope protein truncate refers to a fusion peptide region (FP) VIPLIPLMVGLGLSASTVALG and/or an immunosuppression region (immunosuppressive domains, ISD) of the envelope protein of the present invention

LQNRRGLDLLTAEKGGLCIF and/or transmembrane region (transmembrane domain, TMD)

LPIVSPLIPIFLLLLFGPCIF single or multiple deletion mutations, preferably the envelope protein truncations C-terminal transmembrane protein TM.

The HERV-F envelope protein mutant refers to an envelope protein mutant generated by mutating single or multiple amino acids of an envelope protein immune suppression domain ISD conserved region amino acid L (A) Q (A) NRRGLDMLTAAQ (R) GGICLA (F) L414A (or other amino acids), Q415A (or other amino acids) Q427R (or other amino acids) and A433F (or other amino acids). Preferred are mutation site amino acids L414A, Q415A, Q427R and A433F, more preferred is the envelope protein mutant C-terminal transmembrane protein TM.

The HERV-F envelope protein truncate refers to a fusion peptide region (FP) AIHFIPLLAGLGILAGTGTGIAGITK and/or an immunosuppression region (immunosuppressive domains, ISD) LQNRRGLDMLTAAQGGI and/or a transmembrane region (transmembrane domain, TMD) of the envelope protein of the present invention

WFSWVLPLTGPLVSLLLLLLF. The envelope protein truncations generated by deletion mutation, singly or multiply, are preferably envelope protein truncations C-terminal transmembrane protein TM.

The specific amino acid sequence is as follows:

SEQ ID NO. 1 No. 1-1-XUKMV (Mutant) (K108-Env Mutant, K108 envelope protein)

MNPSEMQRKAPPRRRRHRNRAPLTHKMNKMVTSEEQMKLPSTKKAEPPTWAQLKKLTQLATKY

LENTKVTQTPESMLLAALMIVSMVVSLPMPAGAAAANYTYWAYVPFPPLIRAVTWMDNPTEVYVNDS

VWVPGPIDDRCPAKPEEEGMMINISIGYHYPPICLGRAPGCLMPAVQNWLVEVPTVSPICRFTYHMVSGM

SLRPRVNYLQDFSYQRSLKFRPKGKPCPKEIPKESKNTEVLVWEECVANSAVILQNNEFGTIIDWAPRGQF

YHNCSGQTQSCPSAQVSPAVDSDLTESLDKHKHKKLQSFYPWEWGEKGISTPRPKIVSPVSGPEHPELWRL

TVASHHIRIWSGNQTLETRDRKPFYTIDLNSSLTVPLQSCVKPPYMLVVGNIVIKPDSQTITCENCRLLTCID

STFNWQHRILLVRAREGVWIPVSMDRPWEASPSVHILTEVLKGVLNRSKRFIFTLIAVIMGLIAVTATAAVA

GVALHSSVQSVNFVNDWQKNSTRLWNSQSSIDQKAGNQINDLRQTVIRMGDRLMSLEHRFQLQCDWNT

SDFCITPQIYNESEHHWDMVRRHLQGREDNLTLDISKLKEQIFEASKAHLNLVPGTEAIAGVADGLANLNP

VTWVKTIGSTTIINLILILVCLFCLLLVCRCTQQLRRDSDHRERAMMTMAVLSKRKGGNVGKSKRDQIVT

VSV(699aa).

SEQ ID NO. 2 No. 1-2-XUKMV (Mutant) (K108-TM Mutant, K108 transmembrane protein) )FIFTLIAVIMGLIAVTATAAVAGVALHSSVQSVNFVNDWQKNSTRLWNSQSSIDQKAGNQINDLRQTVIRMGDRLMSLEHRFQLQCDWNTSDFCITPQIYNESEHHWDMVRRHLQGREDNLTLDISKLKEQIFEASKAHLNLVPGTEAIAGVADGLANLNPVTWVKTIGSTTIINLILILVCLFCLLLVCRCTQQLRRDSDHRERAMMTMAVLSKRKGGNVGKSKRDQIVTVSV(234aa).

SEQ ID NO. 3 No. 2-1-XUKMV (Mutant of K102-Env Mutant, K102 envelope protein) )MVTPVTWMDNPIEIYVNDSVWVPGPIDDRCPAKPEEEGMMINISIGYRYPPICLGRAPGCLMPAVQNWLVEVPTVSPISRFTYHMVSGMSLRPRVNYLQDFSYQRSLKFRPKGKPCPKEIPKESKNTEVLVWEECVANSAVILQNNEFGTIIDWAPRGQFYHNCSGQTQSCPSAQVSPAVDSDLTESLDKHKHKKLQSFYPWEWGEKGISTPRPKIVSPVSGPEHPELWRLTVASHHIRIWSGNQTLETRDCKPFYTIDLNSSLTVPLQSCVKPPYMLVVGNIVIKPDSQTITCENCRLLTCIDSTFNWQHRILLVRAREGVWIPVSMDRPWEASPSVHILTEVLKGVLNRSKRFIFTLIAVIMGLIAVTATAAVAGVALHSSVQSVNFVNDWQKNSTRLWNSQSSIDQKAGNQINDLRQTVIRMGDRLMSLEHRFQLQCDWNTSDFCITPQIYNESEHHWDMVRRHLQGREDNLTLDISKLKEQIFEASKAHLNLVPGTEAIAGVADGLANLNPVTWVKTIGSTTIINLILILVCLFCLLLVCRCTQQLRRDSDHRERAMMTMAVLSKRKGGNVGKSKRDQIVTVSV(588aa).

SEQ ID NO. 4 No. 2-2-XUKMV (Mutant) (K102-TM Mutant, K102 transmembrane protein Mutant) )FIFTLIAVIMGLIAVTATAAVAGVALHSSVQSVNFVNDWQKNSTRLWNSQSSIDQKAGNQINDLRQTVIRMGDRLMSLEHRFQLQCDWNTSDFCITPQIYNESEHHWDMVRRHLQGREDNLTLDISKLKEQIFEASKAHLNLVPGTEAIAGVADGLANLNPVTWVKTIGSTTIINLILILVCLFCLLLVCRCTQQLRRDSDHRERAMMTMAVLSKRKGGNVGKSKRDQIVTVSV(234aa)

SEQ ID NO. 5 No. 3-1-XUKTV (truncated) (K108-Env Truncation, K108 envelope protein truncations) )MNPSEMQRKAPPRRRRHRNRAPLTHKMNKMVTSEEQMKLPSTKKAEPPTWAQLKKLTQLATKYLENTKVTQTPESMLLAALMIVSMVVSLPMPAGAAAANYTYWAYVPFPPLIRAVTWMDNPTEVYVNDSVWVPGPIDDRCPAKPEEEGMMINISIGYHYPPICLGRAPGCLMPAVQNWLVEVPTVSPICRFTYHMVSGMSLRPRVNYLQDFSYQRSLKFRPKGKPCPKEIPKESKNTEVLVWEECVANSAVILQNNEFGTIIDWAPRG

QFYHNCSGQTQSCPSAQVSPAVDSDLTESLDKHKHKKLQSFYPWEWGEKGISTPRPKIVSPVSGPEHPEL

WRLTVASHHIRIWSGNQTLETRDRKPFYTIDLNSSLTVPLQSCVKPPYMLVVGNIVIKPDSQTITCENCRLL

TCIDSTFNWQHRILLVRAREGVWIPVSMDRPWEASPSVHILTEVLKGVLNRSKRAGVALHSSVQSVNFV

NDWQKNSTRLWNSQSSIDQKRLMSLEHRFQLQCDWNTSDFCITPQIYNESEHHWDMVRRHLQGREDNL

TLDISKLKEQIFEASKAHLNLVPGTEAIAGVADGLANLNPVTWVKTVCRCTQQLRRDSDHRERAMMTM

AVLSKRKGGNVGKSKRDQIVTVSV(640aa)

SEQ ID NO. 6 No. 3-2-XUKTV (truncated) (K108-TM Truncation, K108 transmembrane protein truncations)

AGVALHSSVQSVNFVNDWQKNSTRLWNSQSSIDQKRLMSLEHRFQLQCDWNTSDFCITPQIYNESEHH

WDMVRRHLQGREDNLTLDISKLKEQIFEASKAHLNLVPGTEAIAGVADGLANLNPVTWVKTVCRCTQQ

LRRDSDHRERAMMTMAVLSKRKGGNVGKSKRDQIVTVSV(175aa)

SEQ ID NO. 7 No. 4-1-XUKMV (truncated) (K102-Env Truncation, K102 envelope protein truncations)

MVTPVTWMDNPIEIYVNDSVWVPGPIDDRCPAKPEEEGMMINISIGYRYPPICLGRAPGCLMPAVQNWLV

EVPTVSPISRFTYHMVSGMSLRPRVNYLQDFSYQRSLKFRPKGKPCPKEIPKESKNTEVLVWEECVANSA

VILQNNEFGTIIDWAPRGQFYHNCSGQTQSCPSAQVSPAVDSDLTESLDKHKHKKLQSFYPWEWGEKGIS

TPRPKIVSPVSGPEHPELWRLTVASHHIRIWSGNQTLETRDCKPFYTIDLNSSLTVPLQSCVKPPYMLVVG

NIVIKPDSQTITCENCRLLTCIDSTFNWQHRILLVRAREGVWIPVSMDRPWEASPSVHILTEVLKGVLNRS

KRAGVALHSSVQSVNFVNDWQKNSTRLWNSQSSIDQKRLMSLEHRFQLQCDWNTSDFCITPQIYNESEH

HWDMVRRHLQGREDNLTLDISKLKEQIFEASKAHLNLVPGTEAIAGVADGLANLNPVTWVKTVCRCTQ

QLRRDSDHRERAMMTMAVLSKRKGGNVGKSKRDQIVTVSV(529aa)

SEQ ID NO. 8 No. 4-2-XUKMV (truncated) (K102-TM Truncation, K102 transmembrane protein truncations)

AGVALHSSVQSVNFVNDWQKNSTRLWNSQSSIDQKRLMSLEHRFQLQCDWNTSDFCITPQIYNESEHH

WDMVRRHLQGREDNLTLDISKLKEQIFEASKAHLNLVPGTEAIAGVADGLANLNPVTWVKTVCRCTQQ

LRRDSDHRERAMMTMAVLSKRKGGNVGKSKRDQIVTVSV(175aa)

SEQ ID NO. 9 No. 5-1-XUFMV (F-Env Mutant, F envelope protein Mutant)

MGLLLLVLILTPSLAAYRHPDFPLLEKAQQLLQSTGSPYSTNCWLCTSSSTETPGTAYPASPREWTSIEAEL

HISYRWDPNLKGLMRPANSLLSTVKQDFPDIRQKPPIFGPIFTNINLMGIAPICVMAKRKNGTNVGTLPST

VCNVTFTVDSNQQTYQTYTHNQFRHQPRFPKPPNITFPQGTLLDKSSRFCQGRPSSCSTRNFWFRPADYN

QCLQISNLSSTAEWVLLDQTRNSLFWENKTKGANQSQTPCVQVLAGMTIATSYLGISAVSEFFGTSLTPLF

HFHISTCLKTQGAFYICGQSIHQCLPSNWTGTCTIGYVTPDIFIAPGNLSLPIPIYGNSPLPRVRRAIHFIPLL

AGLGILAGTGTGIAGITKASLTYSQLSKEIANNIDTMAKALTTMQEQIDSLAAVVAANRRGLDMLTAARG

GICLFLDEKCCFWVNQSGKVQDNIRQLLNQASSLRERATQGWLNWEGTWKWFSWVLPLTGPLVSLLLL

LLFGPCLLNLITQFVSSRLQAIKLQTNLSAGRHPRNIQESPF(538aa)

SEQ ID NO. 10 No. 5-2-XUFMV (F-TM Mutant, F transmembrane protein Mutant)

AIHFIPLLAGLGILAGTGTGIAGITKASLTYSQLSKEIANNIDTMAKALTTMQEQIDSLAAVVAANRRGLD

MLTAARGGICLFLDEKCCFWVNQSGKVQDNIRQLLNQASSLRERATQGWLNWEGTWKWFSWVLPLTG

PLVSLLLLLLFGPCLLNLITQFVSSRLQAIKLQTNLSAGRHPRNIQESPF(188aa)

SEQ ID NO. 11 No. 6-1-XUFTV (F-Env Truncation, F envelope protein truncations)

MGLLLLVLILTPSLAAYRHPDFPLLEKAQQLLQSTGSPYSTNCWLCTSSSTETPGTAYPASPREWTSIEAEL

HISYRWDPNLKGLMRPANSLLSTVKQDFPDIRQKPPIFGPIFTNINLMGIAPICVMAKRKNGTNVGTLPST

VCNVTFTVDSNQQTYQTYTHNQFRHQPRFPKPPNITFPQGTLLDKSSRFCQGRPSSCSTRNFWFRPADYN

QCLQISNLSSTAEWVLLDQTRNSLFWENKTKGANQSQTPCVQVLAGMTIATSYLGISAVSEFFGTSLTPLF

HFHISTCLKTQGAFYICGQSIHQCLPSNWTGTCTIGYVTPDIFIAPGNLSLPIPIYGNSPLPRVRRASLTYSQ

LSKEIANNIDTMAKALTTMQEQIDSLAAVVCLALDEKCCFWVNQSGKVQDNIRQLLNQASSLRERATQG

WLNWEGTWKGPCLLNLITQFVSSRLQAIKLQTNLSAGRHPRNIQESPF(474aa)

SEQ ID NO. 12 No. 6-2-XUFTV (F-TM Truncation, F transmembrane protein truncations)

ASLTYSQLSKEIANNIDTMAKALTTMQEQIDSLAAVVCLALDEKCCFWVNQSGKVQDNIRQLLNQASSL RERATQGWLNWEGTWKGPCLLNLITQFVSSRLQAIKLQTNLSAGRHPRNIQESPF(124aa)

SEQ ID NO. 13 No. 7-1-XUHMV (H-Env Mutant of envelope protein)

MIFAGKAPSNTSTLMKFYSLLLYSLLFSFPFLCHPLPLPSYLHHTINLTHSLLAASNPSLVNNCWLCISLSSS

AYTAVPAVQTDWATSPISLHLRTSFNSPHLYPPEELIYFLDRSSKTSPDISHQQAAALLRTYLKNLSPYINST

PPIFGPLTTQTTIPVAAPLCISWQRPTGIPLGNLSPSRCSFTLHLRSPTTNINETIGAFQLHITDKPSINTDKLK

NISSNYCLGRHLPCISLHPWLSSPCSSDSPPRPSSCLLIPSPENNSERLLVDTRRFLIHHENRTFPSTQLPHQS

PLQPLTAAALAGSLGVWVQDTPFSTPSHLFTLHLQFCLAQGLFFLCGSSTYMCLPANWTGTCTLVFLTPKI

QFANGTEELPVPLMTPTQQKRVIPLIPLMVGLGLSASTVALGTGIAGISTSVMTFRSLSNDFSASITDISQT

LSVLQAQVDSLAAVVAANRRGLDLLTAERGGLCIFLNEECCFYLNQSGLVYDNIKKLKDRAQKLANQAS

NYAEPPWALSNWMSWVLPIVSPLIPIFLLLLFGPCIFRLVSQFIQNRIQAITNHSIRQMFLLTSPQYHPLPQDLPSA(584aa)

SEQ ID NO. 14 No. 7-2-XUHMV (H-TM Mutant, H transmembrane protein Mutant)

VIPLIPLMVGLGLSASTVALGTGIAGISTSVMTFRSLSNDFSASITDISQTLSVLQAQVDSLAAVVAANRRG

LDLLTAERGGLCIFLNEECCFYLNQSGLVYDNIKKLKDRAQKLANQASNYAEPPWALSNWMSWVLPIVS PLIPIFLLLLFGPCIFRLVSQFIQNRIQAITNHSIRQMFLLTSPQYHPLPQDLPSA(197aa)

SEQ ID NO. 15 No. 8-1-XUHTV (H-Env Truncation, H envelope protein truncations)

MIFAGKAPSNTSTLMKFYSLLLYSLLFSFPFLCHPLPLPSYLHHTINLTHSLLAASNPSLVNNCWLCISLSSS

AYTAVPAVQTDWATSPISLHLRTSFNSPHLYPPEELIYFLDRSSKTSPDISHQQAAALLRTYLKNLSPYINST

PPIFGPLTTQTTIPVAAPLCISWQRPTGIPLGNLSPSRCSFTLHLRSPTTNINETIGAFQLHITDKPSINTDKLK

NISSNYCLGRHLPCISLHPWLSSPCSSDSPPRPSSCLLIPSPENNSERLLVDTRRFLIHHENRTFPSTQLPHQS

PLQPLTAAALAGSLGVWVQDTPFSTPSHLFTLHLQFCLAQGLFFLCGSSTYMCLPANWTGTCTLVFLTPKI

QFANGTEELPVPLMTPTQQKRTGIAGISTSVMTFRSLSNDFSASITDISQTLSVLQAQVDSLAAVVLNEEC

CFYLNQSGLVYDNIKKLKDRAQKLANQASNYAEPPWALSNWMSWVRLVSQFIQNRIQAITNHSIRQMFLLTSPQYHPLPQDLPSA(522aa)

SEQ ID NO. 16 No. 8-2-XUHTV (H-TM Truncation, H transmembrane protein truncations)

RTGIAGISTSVMTFRSLSNDFSASITDISQTLSVLQAQVDSLAAVVLNEECCFYLNQSGLVYDNIKKLKDR AQKLANQASNYAEPPWALSNWMSWVRLVSQFIQNRIQAITNHSIRQMFLLTSPQYHPLPQDLPSA(136aa)

The foregoing examples illustrate only a few embodiments of the application and are described in detail herein without thereby limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims. All documents referred to in this disclosure are incorporated by reference herein as if each was individually incorporated by reference.

Claims

1. A mutant or truncation of a human endogenous retrovirus envelope protein, characterized in that a single or multiple amino acids in the immunosuppressive domain of the mutant or truncation are mutated;

The immunosuppressive domain is an immunosuppressive region;

The human endogenous retrovirus is HERV-H;

The corresponding amino acid sequence is:

The sequence of the HERV-H envelope protein mutant is shown in SEQ ID NO: 13,

The sequence of the HERV-H envelope protein truncate is shown in SEQ ID NO:15.

2. A mutant or truncation of a human endogenous retrovirus envelope protein, characterized in that the mutant or truncation is a transmembrane protein formed by hydrolyzing the human endogenous retrovirus envelope protein with furin protease, and the corresponding amino acid sequence is:

The sequence of the HERV-H transmembrane protein mutant is shown in SEQ ID NO: 14,

The sequence of the HERV-H transmembrane protein truncate is shown in SEQ ID NO:16.

3. A drug, characterized in that the drug comprises the human endogenous retrovirus envelope protein mutant or truncation according to any one of claims 1 to 2.