CN114457032A - A pluripotent stem cell expressing B7-H4 blocker or its derivative and application - Google Patents

Abstract

The invention discloses a pluripotent stem cell expressing a B7-H4 blocker or a derivative thereof and application thereof, wherein the genome of the pluripotent stem cell or the derivative thereof is introduced with an expression sequence of a B7-H4 blocker, and the B7-H4 blocker is an anti-B7-H4 antibody. The pluripotent stem cells or derivatives thereof expressing the B7-H4 blocker provided by the invention can be used for inducing iPSCs (induced pluripotent stem cells) or differentiating the iPSCs into low-immunogenicity cells such as MSCs (mesenchymal stem cells) for application, can continuously express the B7-H4 blocker in vivo, and are used for treating B7-H4 high-expression tumors and related diseases.

Description

A pluripotent stem cell expressing B7-H4 blocker or its derivative and application

technical field

The invention belongs to the technical field of genetic engineering, and in particular relates to a pluripotent stem cell expressing a B7-H4 blocker or a derivative thereof and application thereof.

Background technique

B7-H4 (B7H4, also known as B7s1 and B7x) is a member of the B7 family. The B7-H4 protein is composed of a signal peptide region, a pair of V, C immunoglobulin outer segments, a transmembrane region and a cytoplasmic region. It is a type I transmembrane glycoprotein and is riveted to the cell membrane by GPI. The cross-linking of H4 through GPI facilitates access to major histocompatibility complex (MHC) molecules and such a spatial structure facilitates the mediation of negative co-stimulatory effects. B7H4 is expressed on professional antigen presenting cells (APCs) and is widely distributed in non-lymphoid tissues. It can negatively regulate the immune response of T cells by inhibiting T cell proliferation, cytokine production and cell cycle progression. In recent years, studies have found that B7-H4 is highly expressed on the surface of various tumor cells, such as lung cancer, ovarian cancer, breast cancer, gastric cancer, esophageal cancer, kidney cancer, melanoma, etc. The expression of B7-H4 is related to tumor division , staging and prognosis are closely related. It is also highly expressed on the surface of tumor vascular endothelial cells and tumor-infiltrating macrophages and dendritic cells. The expression of B7-H4 in tumor tissues of patients with lung cancer, colorectal cancer, breast cancer, and gastric cancer was detected by immunohistochemical technique, and it was found that the above tumor tissues highly expressed B7-H4. B7-H4 can also exist in human blood and other body fluids in a soluble form (soluble B7-H4, sB7-H4). It has been found that the level of sB7-H4 in peripheral blood of patients with various tumors is increased. In some animal models, B7-H4 has been found to be highly expressed on tumor cells, which can inhibit apoptosis and stimulate tumor growth. B7-H4 has extensive and diverse glycosylation, which is a barrier for tumor cells to evade immune surveillance. In tumor progression, B7-H4 plays a role in transforming precancerous cells and evading immune surveillance. For example, in an immunodeficient mouse model of ovarian cancer, high expression of B7-H4 stimulates tumor formation, mainly by stimulating Cell proliferation, increased cell adhesion, metastasis, and invasion were achieved, suggesting that B7-H4 may directly stimulate tumorigenesis independent of immune factors. Overexpression of B7-H4 in normal epithelial cells can lead to their malignant transformation, mainly inhibiting cell apoptosis. In vitro experiments, tumor cell lines with siRNA interference with the B7-H4 gene accelerated apoptosis. Therefore, B7-H4 has become a new target for the treatment of tumors, and B7-H4 blockers (anti-B7-H4 antibodies) can be used as tumor therapeutic drugs. However, anti-B7-H4 antibodies have a short duration of action and require long-term injections, which are expensive for patients.

Stem cells are a type of "seed" cells that have the ability to self-renew and differentiate into specific functional somatic cells. They have the potential to regenerate into various tissues and organs and the human body. core and irreplaceable role. According to the degree of stem cell characteristics, stem cells are mainly divided into: totipotent stem cells (Totipotent stem cells), pluripotent stem cells (PSCs) and adult stem cells (adult stem cells). Among them, pluripotent stem cells (PSCs) have almost unlimited self-renewal ability and the potential to develop and differentiate into organs, tissues and cells of all germ layers in the embryo under normal developmental conditions. Typical PSCs mainly include embryonic stem cells (ESCs). ), embryonic germ cells (EGCs), embryonic carcinoma cells (ECCs), and induced pluripotentstem cells (iPSCs). It can pass ethical restrictions to a certain extent, so it has a very far-reaching and wide-ranging application prospect.

Therefore, it is of great significance to develop a pluripotent stem cell or its derivative that can express B7-H4 blocker in humans.

However, the conception or establishment of an autologous iPSCs cell bank or an immune-matched PSCs cell bank requires enormous financial, material and human resources. The molecular immunological basis of organ, tissue or cell transplantation of allogeneic donors and recipients is mainly based on the classical major histocompatibility complex MHC-I and MHC-II (also known as HLA-I, HLA-II in humans) 's matching. As of June 2019, more than 20,000 HLA system alleles have been identified and named, and only classical HLA-A, B, and C alleles have more than 5,000 alleles. These classical HLA-I/II The number of possible random combinations of alleles will be astronomical, and the number of combinations will increase with the discovery of new alleles, bringing great importance to the tissue matching and donor selection of organs, tissues, and cells before transplantation. This is a huge obstacle, and it also brings huge difficulties to the construction of a population-covering immune-matched PSCs cell bank.

Therefore, the construction of alloimmune compatible universal PSCs is imminent. In recent years, there have been many reports that by knocking out B2M, CIITA and other genes, the expression of HLA-I and HLA-II cells surface or their own genes is lost, so that cells have immune tolerance or escape T/B cell-specific immune responses, resulting in The immune-compatible universal PSCs have laid an important foundation for the wider application of universal PSC-derived cells, tissues and organs. It has also been reported that cells overexpress CTLA4-Ig and PD-L1 to inhibit allogeneic immune rejection. Recently, it has been reported that while knocking out B2M and CIITA, CD47 is knocked in, so that the cells can escape from the specific immune response, but also have immune tolerance or escape the innate immune response of NK cells, so that the cells have More comprehensive and stronger immune compatibility features. However, these regimens are either not fully immune compatible, and allogeneic immune rejection still occurs through other means; or they completely eliminate the allogeneic immune rejection response, but the cells of the donor-derived graft lose their antigen-presenting ability at the same time. capacity, which poses a great risk to the receptor for diseases such as tumorigenicity and viral infection.

For this reason, it has also been reported that, instead of directly knocking out B2M, HLA-A, HLA-B or CIITA are knocked out together, while retaining HLA-C, and constructing 12 HLA-C immune systems that cover more than 90% of the population. Matching antigens, so that the transplanted cells still have a certain degree of antigen presentation function, and at the same time can inhibit the innate immune response of NK cells through HLA-C. However, the types of antigens presented by HLA-I antigens have been reduced by more than two-thirds, and the integrity of the antigens that can be presented has been greatly and irreversibly reduced. For various tumors, viruses and other disease antigens The presentation is highly biased, and still retains a considerable degree of risk of tumorigenicity and viral infection, and its pathogenic risk is higher when CIITA is knocked out at the same time; secondly, 12 high-frequency immune matching The ethnic differences of HLA-C antigens are very large. Through our verification and calculation, some regions can only account for 70% of the proportion. However, China, India and other populous countries currently do not have authoritative large-scale HLA data display. The use of type PSCs is still subject to the huge matching vacancy test; thirdly, this method will undergo several iterations of gene editing work. Based on at least two rounds of single-cell isolation and culture for each gene editing, the whole process requires at least more than six rounds of single-cell isolation and culture. Cell isolation and culture, these processes are inevitably and highly likely to cause various unpredictable mutations in cells due to multiple off-target gene editing or chromatin instability or due to a large number of single-cell passages and proliferations, and then induce various problems such as carcinogenesis and metabolic diseases . It can be seen that this type of immunocompatibility program is also an expedient measure in the "transition period", and there are still many problems that have not been better resolved.

In addition, some people have designed suicide genes to induce killing after the donor tissue and cells become diseased. The consequences of doing so will cause severe tissue necrosis, cytokine storms and other unpredictable disease risk problems, and such designed cells Another problem is that after killing, there will be no suitable donor cells, tissues and organs.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies in the prior art, the first aspect of the present invention aims to provide a pluripotent stem cell or its derivatives expressing a B7-H4 blocker, including non-immune cells expressing a B7-H4 blocker. Compatible pluripotent stem cells or derivatives thereof, immunocompatible pluripotent stem cells or derivatives thereof expressing B7-H4 blockers, immunocompatibility reversible pluripotent stem cells or derivatives thereof expressing B7-H4 blockers At least one; wherein, the immune-compatible pluripotent stem cells or derivatives thereof expressing the B7-H4 blocker can be achieved by the following scheme: knocking out the B2M and/or CIITA genes in the genome of the pluripotent stem cells or their derivatives and /or into the genome of pluripotent stem cells or their derivatives to introduce the expression sequences of immune-compatible molecules; the immune-compatible and reversible pluripotent stem cells or their derivatives expressing B7-H4 blockers are achieved by the following scheme: in pluripotent stem cells or their derivatives The genome of derivatives is introduced into immune-compatible molecules and inducible gene expression systems. The expression of immune-compatible molecules introduced into the genomes of pluripotent stem cells or their derivatives is regulated by the inducible gene expression system, and the opening and closing of the inducible gene expression system is controlled by Regulation of exogenous inducers; when immune-compatible molecules are normally expressed, the expression of genes related to immune response in pluripotent stem cells or their derivatives is inhibited or overexpressed, which can eliminate or reduce the interaction between donor cells and recipients. Allogeneic immune rejection response; and when the donor cells are diseased, the expression of immune-compatible molecules can be induced to shut down by exogenous inducers, restoring the antigen-presenting ability of the donor cells, and enabling the recipient to clear the diseased donor cells. .

The purpose of the second aspect of the present invention is to provide the application of the above-mentioned pluripotent stem cells or derivatives thereof in the preparation of drugs for the treatment of tumors with high B7-H4 expression.

The object of the third aspect of the present invention is to provide a preparation comprising the above-mentioned pluripotent stem cells or derivatives thereof.

In order to achieve the above object, the technical scheme adopted by the present invention is:

A first aspect of the present invention provides a pluripotent stem cell or a derivative thereof expressing a B7-H4 blocker, wherein the genome of the pluripotent stem cell or its derivative is introduced with the expression sequence of the B7-H4 blocker, The B7-H4 blocker is an anti-B7-H4 antibody.

The heavy chain sequence of the anti-B7-H4 antibody is shown in SEQ ID NO.1, and the light chain sequence is shown in SEQ ID NO.2.

The anti-B7-H4 antibody is preferably a secreted antibody.

The introduction site of the expression sequence of the B7-H4 blocker is the genomic safety site of the pluripotent stem cell or its derivative.

The genomic safety site includes one or more of the AAVS1 safety site, the eGSH safety site, and the H11 safety site.

As another technical solution of the present invention: the B2M and/or CIITA genes of the pluripotent stem cells or their derivatives are knocked out, thereby obtaining an immune-compatible pluripotent stem cell or its derivatives expressing a B7-H4 blocker thing.

As another technical solution of the present invention: the genome of the pluripotent stem cells or their derivatives is further introduced with one or more immune-compatible molecule expression sequences, and the immune-compatible molecules are used to regulate the pluripotent stem cells or their derivatives. Expression of genes associated with immune response (allogeneic immune rejection), resulting in an immune-compatible pluripotent stem cell or derivative thereof expressing a B7-H4 blocker.

The genes associated with the immune response include:

(1) Major histocompatibility complex genes, including HLA-A, HLA-B, HLA-C, HLA-DRA, HLA-DRB1, HLA-DRB3, HLA-DRB4, HLA-DRB5, HLA-DQA1, HLA - at least one of DQB1, HLA-DPAl and HLA-DPB1;

(2) Major histocompatibility complex-related genes, including at least one of B2M and CIITA.

The introduction site of the immunocompatible molecule expression sequence is the genome safety site of the pluripotent stem cell or its derivative.

The genomic safety site includes one or more of the AAVS1 safety site, the eGSH safety site, and the H11 safety site.

The immunocompatible molecule includes any one or more of the following:

(1) Immune tolerance-related genes, including CD47 or HLA-G;

(2) HLA-C class molecules, including HLA-C multiple alleles with a proportion of more than 90% in the population, or fusion protein genes composed of more than 90% of HLA-C multiple alleles and B2M;

(3) shRNA and/or shRNA-miR of major histocompatibility complex genes, the major histocompatibility complex genes include HLA-A, HLA-B, HLA-C, HLA-DRA, HLA-DRB1 , at least one of HLA-DRB3, HLA-DRB4, HLA-DRB5, HLA-DQA1, HLA-DQB1, HLA-DPA1 and HLA-DPB1;

(4) shRNA and/or shRNA-miR of a major histocompatibility complex-related gene, the major histocompatibility complex-related gene including at least one of B2M and CIITA.

The target sequence of the B2M shRNA and/or shRNA-miR is at least one of SEQ ID NO.3 to SEQ ID NO.5;

The target sequence of the shRNA and/or shRNA-miR of the CIITA is at least one of SEQ ID NO.6 to SEQ ID NO.15;

The target sequence of the HLA-A shRNA and/or shRNA-miR is at least one of SEQ ID NO.16 to SEQ ID NO.18;

The target sequence of the HLA-B shRNA and/or shRNA-miR is at least one of SEQ ID NO.19-SEQ ID NO.24;

The target sequence of the HLA-C shRNA and/or shRNA-miR is at least one of SEQ ID NO.25-SEQ ID NO.30;

The target sequence of the shRNA and/or shRNA-miR of the HLA-DRA is at least one of SEQ ID NO.31-SEQ ID NO.40;

The target sequence of the shRNA and/or shRNA-miR of the HLA-DRB1 is at least one of SEQ ID NO.41-SEQ ID NO.45;

The target sequence of the shRNA and/or shRNA-miR of the HLA-DRB3 is at least one of SEQ ID NO.46-SEQ ID NO.47;

The target sequence of the shRNA and/or shRNA-miR of the HLA-DRB4 is at least one of SEQ ID NO.48-SEQ ID NO.57;

The target sequence of the shRNA and/or shRNA-miR of the HLA-DRB5 is at least one of SEQ ID NO.58-SEQ ID NO.66;

The target sequence of the shRNA and/or shRNA-miR of the HLA-DQA1 is at least one of SEQ ID NO.67-SEQ ID NO.73;

The target sequence of the shRNA and/or shRNA-miR of the HLA-DQB1 is at least one of SEQ ID NO.74-SEQ ID NO.83;

The target sequence of the shRNA and/or shRNA-miR of the HLA-DPA1 is at least one of SEQ ID NO.84-SEQ ID NO.93;

The target sequence of the shRNA and/or shRNA-miR of the HLA-DPB1 is at least one of SEQ ID NO.94-SEQ ID NO.103.

shRNA and/or miRNA processing complex-related genes and/or anti-interferon effector molecules are also introduced into the genome of the pluripotent stem cells or derivatives thereof.

The shRNA and/or miRNA processing complex-related genes include at least one of Drosha, Ago1, Ago2, Dicer1, Exportin-5, TRBP (TARBP2), PACT (PRKRA), and DGCR8; the anti-interferon effector molecule is shRNA and/or shRNA-miR of at least one of PKR, 2-5As, IRF-3, and IRF-7.

The introduction site of the shRNA and/or miRNA processing complex-related gene and/or the anti-interferon effector molecule is the genomic safety site of the pluripotent stem cell or its derivative.

The genomic safety site includes one or more of the AAVS1 safety site, the eGSH safety site, and the H11 safety site.

The target sequence of the shRNA and/or shRNA-miR of the PKR is at least one of SEQ ID NO.104-SEQ ID NO.113;

The target sequence of the 2-5As shRNA and/or shRNA-miR is at least one of SEQ ID NO.114-SEQ ID NO.143;

The target sequence of the shRNA and/or shRNA-miR of the IRF-3 is at least one of SEQ ID NO.144-SEQ ID NO.153;

The target sequence of the shRNA and/or shRNA-miR of IRF-7 is at least one of SEQ ID NO.154-SEQ ID NO.163.

The expression framework of the major histocompatibility complex gene, major histocompatibility complex-related gene, PKR, 2-5As, IRF-3 or IRF-7 shRNA and/or shRNA-miR is as follows:

(1) shRNA expression framework: from 5' to 3', it includes the shRNA target sequence, the stem-loop sequence, the reverse complement of the shRNA target sequence, and Poly T; the two reverse complement target sequences are separated by a stem-loop sequence in the middle. Hairpin structure, finally connected with Poly T as the transcription terminator of RNA polymerase III;

(2) shRNA-miR expression framework: use the above-mentioned major histocompatibility complex gene, major histocompatibility complex-related gene, PKR, 2-5As, IRF-3 or IRF-7 shRNA-miR target sequence replacement Target sequences in microRNA-30 or microRNA-155 were obtained.

The length of the stem-loop sequence in the shRNA expression framework is 3-9 bases; the length of the poly T is 5-6 bases.

The above-mentioned expression framework can add a constitutive promoter or an inducible promoter at the 5' end as required, such as U6 promoter, H1 promoter, and matching promoter regulatory elements.

As another technical solution of the present invention: an inducible gene expression system is also introduced into the genome of the pluripotent stem cells or their derivatives for regulating the expression of immune-compatible molecules, thereby obtaining an immune-compatible and reversible expression B7-H4 Blocker of pluripotent stem cells or derivatives thereof.

The inducible gene expression system is at least one of Tet-Off system and dimer inducible expression system.

The introduction site of the inducible gene expression system is the genomic safety site of pluripotent stem cells or derivatives thereof.

The genomic safety site includes one or more of the AAVS1 safety site, the eGSH safety site, and the H11 safety site.

The expression sequences of the above-mentioned B7-H4 blockers, the expression sequences of immune-compatible molecules, shRNA and/or miRNA processing complex-related genes, anti-interferon effector molecules, and inducible gene expression systems were introduced using viral vector interference, non- Methods for viral vector transfection or gene editing.

The method of gene editing includes gene knock-in.

The pluripotent stem cells described above include embryonic stem cells, embryonic germ cells, embryonic cancer cells, or induced pluripotent stem cells; the pluripotent stem cell derivatives include adult stem cells, cells or tissues of various germ layers differentiated from pluripotent stem cells.

The adult stem cells include mesenchymal stem cells and neural stem cells.

The second aspect of the present invention provides the use of the above-mentioned pluripotent stem cells or derivatives thereof in the preparation of a B7-H4 high-expressing tumor therapeutic drug.

A third aspect of the present invention provides a preparation comprising the above-mentioned pluripotent stem cells or derivatives thereof.

The formulation also includes a pharmaceutically acceptable carrier, diluent or excipient.

The beneficial effects of the present invention are:

The pluripotent stem cells or derivatives thereof expressing the B7-H4 blocker provided by the present invention can be used for autologous cells to induce iPSCs or differentiate into low-immunogenic cells such as MSCs, and they can continuously express the B7-H4 blocker in vivo. It is used to treat tumors with high expression of B7-H4 and related diseases.

The immune-compatible pluripotent stem cells or derivatives thereof expressing the B7-H4 blocker provided by the present invention are due to the knockout of B2M and CIITA genes in the pluripotent stem cells or their derivatives, or the introduction of immune-compatible molecules into their genomes. Expression sequences, so that such pluripotent stem cells or their derivatives are of low immunogenicity, and when transplanted into recipients, can overcome the problem of allogeneic immune rejection between donor cells and recipients, allowing the donor cells to The B7-H4 blocker can be expressed continuously in the receptor for a long time.

An inducible gene expression system and an immune-compatible molecular expression sequence are introduced into the genome of the immune-compatible and reversible pluripotent stem cells or derivatives thereof expressing the B7-H4 blocker provided by the present invention. The inducible gene expression system is regulated by exogenous inducers. By adjusting the addition amount, duration and type of exogenous inducers, the inducible gene expression system can be turned on and off, thereby controlling the expression of immune-compatible molecular expression sequences. . And immune-compatible molecules can regulate the expression of immune response-related genes in pluripotent stem cells or their derivatives. When immune-compatible molecules are normally expressed, the expression of genes related to immune response in pluripotent stem cells or their derivatives is inhibited or overexpressed, which can eliminate or reduce the allogeneic immune rejection response between donor cells and recipients, This enables the donor cells to express the B7-H4 blocker in the recipient for a prolonged period of time. When the donor cell becomes diseased, the expression of immune-compatible molecules can be induced to shut down by exogenous inducers, thereby reversibly re-expressing HLA class I molecules on the surface of the donor cell, restoring the antigen-presenting ability of the donor cell, and making the recipient It can remove diseased cells, thereby improving the clinical safety of such universal pluripotent stem cells or their derivatives, and greatly expanding their value in clinical applications.

In addition, by adjusting the amount of exogenous inducer and the duration of action, the graft can gradually express low concentrations of HLA molecules to stimulate the recipient, so that the recipient can gradually develop tolerance to the graft, and finally achieve a stable tolerance. . At this time, even if the unmatched HLA class I molecules expressed on the surface of the transplanted cells can be compatible with the recipient immune system, after inducing and shutting down the expression of immune compatible molecules in the transplanted cells, the recipient's immune system can restore the immune system on the one hand. Recognize the cells with genetic mutations presented by HLA class I molecules in the transplant, and remove the diseased cells; on the other hand, the unmutated part will not be tolerated by the recipient because it is trained by the above inducer to produce allogeneic HLA class I molecules Immune system clearance. Thus, the recipient's immune system only removes the harmful mutation of the graft, and retains the normal function of the graft. The graft immune tolerance program mediated by exogenous inducers can also be implanted after the recipient is completely tolerated, without induction or other ways to induce the on or off surface expression of HLA class I molecules.

Description of drawings

Figure 1 is a map of AAVS1 KI (Knock-in, the same below) Vector (shRNA, constitutive) plasmid.

Figure 2 is the AAVS1 KI Vector (shRNA, inducible) plasmid map.

Figure 3 is the AAVS1 KI Vector (shRNA-miR, constitutive) plasmid map.

Figure 4 is the AAVS1 KI Vector (shRNA-miR, inducible) plasmid map.

Figure 5 is the sgRNA clone B2M-1 plasmid map.

Figure 6 is the sgRNA clone B2M-2 plasmid map.

Figure 7 is the sgRNA clone CIITA-1 plasmid map.

Figure 8 is a map of the sgRNA clone CIITA-2 plasmid.

Figure 9 is a map of the Cas9 (D10A) plasmid.

Figure 10 is the sgRNA Clone AAVS1-1 plasmid map.

Figure 11 is the sgRNA Clone AAVS1-2 plasmid map.

Detailed ways

The content of the present invention will be described in further detail below with reference to specific embodiments and accompanying drawings.

It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention.

The experimental method of unreceipted specific conditions in the following examples, usually according to conventional conditions, such as people such as Sambrook, molecular cloning: conditions described in laboratory manual (New York:Cold Spring Harbor Laboratory Press, 1989), or according to manufacture conditions recommended by the manufacturer. Various common chemical reagents used in the examples are all commercially available products.

1 Experimental materials and methods

1.1 B7-H4 blocker

The heavy chain (HC) sequence of the anti-B7-H4 antibody is shown in SEQ ID NO.1, and the light chain (LC) sequence is shown in SEQ ID NO.2.

1.2 Pluripotent stem cells or their derivatives

Pluripotent stem cells can be selected from embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and other forms of pluripotent stem cells, such as hPSCs-MSCs, NSCs, EBs cells. in:

ESCs: HN4 cells can be used, purchased from Shanghai Chinese Academy of Sciences.

iPSCs: Using our third-generation efficient and safe episomal-iPSCs induction system (6F/BM1-4C), pE3.1-OG--KS and pE3.1-L-Myc--hmiR302 cluster were electroporated into the body In cells, RM1 was cultured for 2 days, BioCISO-BM1 containing 2uM Parnate was cultured for 2 days, BioCISO-BM1 containing 2uM Parnate, 0.25mM sodium butyrate, 3uMCHIR99021 and 0.5uM PD03254901 was cultured for 2 days, and the stem cell medium BioCISO was cultured to 17 The iPSCs clones can be picked in about a day, and the picked iPSCs clones are purified, digested, and passaged to obtain stable iPSCs. For the specific construction method, please refer to: Stem Cell Res Ther. 2017Nov 2;8(1):245.

hPSCs-MSCs: iPSCs were cultured in stem cell medium (BioCISO, containing 10uM TGFβ inhibitor SB431542) for 25 days, digested and passaged at 80-90 confluency (2mg/mL Dispase digestion), and passaged 1:3 into Matrigel-coated cells In the culture plate, then ESC-MSC medium (knockout DMEM medium, containing 10% KSR, NEAA, double antibody, glutamine, β-mercaptoethanol, 10ng/mL bFGF and SB-431542) was cultured, and the medium was changed every day , 80-90 confluency for passage (1:3 passage), continuous culture for 20 days. For the specific construction method, please refer to: Proc Natl Acad Sci US A. 2015; 112(2):530-535.

NSCs: iPSCs were cultured in induction medium (knockout DMEM medium, containing 10% KSR, containing TGF-β inhibitor, BMP4 inhibitor) for 14 days, and rosette-shaped neurons were picked into low-adherence culture plates Cultivated in a 1:1 ratio of DMEM/F12 (containing 1% N2, Invitrogen) and Neurobasal medium (containing 2% B27, Invitrogen), and also containing 20ng/ml bFGF and 20ng/ml EGF, for culture , Digestion using Accutase for digestion and passage. For the specific construction method, please refer to: FASEB J. 2014; 28(11): 4642-4656.

EBs cells: iPSCs with a confluency of 95% were digested with BioC-PDE1 for 6 min, and then scraped into a block using a mechanical scraping method, settled down to the cell mass, and the settled cell mass was transferred to a low-adherence culture plate for use BioCISO-EB1 was cultured for 7 days, and the medium was changed every other day. After 7 days, the cells were transferred to Matrigel-coated culture plates to continue adherent culture with BioCISO. After 7 days, embryoid bodies (EBs) with inner, middle and outer germ layers were obtained. For the specific construction method, please refer to: StemCell Res Ther. 2017Nov 2;8(1):245.

The pluripotent stem cell derivatives also include adult stem cells differentiated from pluripotent stem cells, cells of each germ layer, tissues, and organs; and the adult stem cells include mesenchymal stem cells or neural stem cells.

1.3 Genome Safety Sites

In the technical solution of the present invention, the genomic safety site for gene knock-in can be selected from the AAVS1 safety site, the eGSH safety site, or other safety sites:

(1) AAVS1 safety site

The AAVS1 locus (alias "PPP1R2C locus") is located on chromosome 19 of the human genome and is a validated "safe harbor" site that ensures the intended function of the transferred DNA fragment. This site is an open chromosomal structure, which can ensure that the transferred gene can be transcribed normally, and the insertion of exogenous target fragments at this site has no known side effects on cells.

(2) eGSH safety site

The eGSH safety site is located on chromosome 1 of the human genome and is another "safe harbor" site that has been validated by the paper and can ensure the intended function of the transferred DNA fragment.

(3) Other security sites

The H11 safety site (also called Hipp11), located on human chromosome 22, is a site between the two genes Eif4enif1 and Drg1. It was discovered and named by Simon Hippenmeyer in 2010. Since the H11 site is located in two genes Therefore, the risk of affecting the expression of the endogenous gene after the insertion of the exogenous gene is very small. The H11 locus was verified to be a safe transcriptional activation region between genes and a new "safe harbor" site besides the AAVS1 and eGSH loci.

1.4 Inducible gene expression system

The inducible gene expression system is selected from: tet-Off system or dimer off expression system:

(1) tet-Off system

In the absence of tetracycline, the tTA protein continues to act on the tet promoter, allowing the gene to continue to be expressed. This system is very useful where transgenes need to be maintained in a state of continuous expression. When tetracycline is added, tetracycline can change the structure of the tTA protein so that it cannot bind to the promoter, thereby reducing the level of gene expression it drives. To keep this system "off", tetracycline must be added continuously.

In the present invention, the sequences of the tet-Off system and one or more immune-compatible molecules are knocked into the genome safety site of the pluripotent stem cells, and the expression of the immune-compatible molecules can be accurately turned on or off by adding tetracycline, thereby reversibly regulating the expression of immune-compatible molecules. Expression of major histocompatibility complex-related genes in competent stem cells or their derivatives.

(2) Dimer shutdown expression system

Dimer-mediated gene expression regulation system: There are many ways to chemically regulate the transcription of target genes, the most common is the use of allosteric regulators that affect the activity of transcription factors. One such approach is to use dimerization inducers or dimers to reconstitute active transcription factors on inactive fusion proteins. The most commonly used system uses the natural product rapamydn or a biologically inactive analog as the dimerized drug. Rapamycin (or analog) homoplasmic protein FKBP12 (the protein that FKBP binds to FK506) and a large serine-threonine protein kinase called FRAP [FRBP-rapamycin-related protein, or mTOR ( Mammalian target of rapamycin)] has a high affinity, and has the function of binding with these two proteins, so the two proteins are brought together as a heterodimer. To regulate target gene transcription, a DNA binding domain is fused to one or more FKBP domains, and a transcriptional repression domain is fused to amino acid 93 of FRAP, called FRB, which is sufficient to bind the FKBP-rapamycin complex. The two fusion proteins dimerized only in the presence of rapamycin. Transcription of genes with sites that bind to the DNA binding region is thus inhibited.

1.5 Immunocompatible molecules

The immune compatible molecule can regulate the expression of allogeneic immune rejection-related genes in pluripotent stem cells or derivatives thereof.

The types and sequences of specific immunocompatible molecules are shown in Table 1.

Table 1 Immunocompatible molecules

The target sequences of the above shRNA or shRNA-miR immune-compatible molecules are shown in Table 2.

Table 2 Target sequences of shRNA or shRNA-miR

In the immune-compatible molecular knock-in schemes in Tables 5-6 below, the shRNA or shRNA-miR sequences of each experimental group were the shRNA or shRNA-miR immune-compatible molecules constructed by using the target sequence 1 in Table 2. Those skilled in the art can understand that shRNA or shRNA-miR immune-compatible molecules constructed with other target sequences can also achieve the technical effects of the present invention, which all fall within the protection scope of the claims of the present invention.

1.6 shRNA/miRNA processing complex genes and anti-interferon effector molecules

The primary miRNA (pri-miRNA) in the nucleus is micro-processed by the complex Drosha-DGCR8, and the pri-miRNA is cleaved into the precursor miRNA (pre-miRNA), which will form a hairpin structure. Next, the pre-miRNA is transported out of the nucleus via the Exportin-5-Ran-GTP complex. The RNaseDicer enzyme, which binds to the double-stranded RNA-binding protein TRBP (TARBP2) in the cytoplasm, cleaves pre-miRNAs to their mature lengths, while the miRNAs are still double-stranded. Finally, it is transported into AGO2 to form RISC (RNA-induced silencing complex). One strand of the final miRNA duplex remains in the RISC complex, while the other is excreted and rapidly degraded. As the main binding protein of Drosha, DGCR8 can bind to pri-miRNA through its two double-stranded RNA binding regions at the C-terminus, recruit and guide Drosha to cleave at the correct position of pri-miRNA to produce pre-miRNA, pre-miRNA It is further processed and cleaved by Dicer and TRBP/PACT to form mature miRNA. The deletion or abnormal expression of DGCR8 can affect the splicing activity of Drosha, which in turn affects the activity of miRNAs, leading to the occurrence of diseases. TRBP can recruit Dicer complex miRNAs to form RISC Ago2.

The present invention utilizes the gene knock-in technology to knock-in the shRNA-miR expression sequences for HLA class I molecules and HLA class II molecules that can be inducible to shut down the expression at the safe site of the genome, preferably, the shRNA that can be inducible to shut down the expression and / or miRNA processing machines include Drosha (Accession number: NM_001100412), Ago1 (Accession number: NM_012199), Ago2 (Accession number: NM_001164623), Dicer1 (Accession number: NM_001195573), Exportin-5 (Accession number: NM_020750), TRBP (Accession number: NM_134323), PACT (Accession number: NM_003690) and DGCR8 (Accession number: NM_022720), so that cells do not occupy the processing of other miRNAs and affect cell function.

In addition, in the process of IFN induction, double-stranded RNA-dependent Protein Kinase (PKR), which is a key factor in the entire cell signal transduction pathway, also has 2',5 'Oligoadenylate synthase (2,5-Oligoadenylate Synthetase, 2-5As), these two enzymes are closely related to dsRNA-induced IFN. PKR can inhibit protein synthesis by phosphorylating eukaryotic transcription factors, make cells stagnate in G0/G1 and G2/M phases, and induce apoptosis, while dsRNA can promote 2-5As synthesis, resulting in non-specific RNase, RNaseL. Heterogeneous activation, degrades all mRNA in cells, and causes cell death. The induction specificity of type I interferon is achieved by members of the IRF transcription factor family. In the absence of the expression of IRF-3 and IRF-7 in cells, type I interferon cannot be induced and secreted in many viral infections. In the absence of an IFN response, co-expression of the two proteins is required to restore it.

The present invention utilizes gene knock-in technology to knock-in the expression sequence of immune compatible molecule shRNA-miR at the safe site of the genome, preferably simultaneously knock-in inducible shut-down expression for inhibiting PKR, 2-5As, IRF-3 and IRF-7 Gene shRNA and/or shRNA-miR expression sequences that reduce dsRNA-induced interferon responses, thereby avoiding cytotoxicity.

There is no restriction on the insertion positions of shRNA/miRNA processing complex-related genes, anti-interferon effector molecules, and immune-compatible molecules in the safe sites of the genome, and they can be arranged in any order without interfering with each other or affecting other genes in the genome. structure and function.

The target sequences of specific anti-interferon effector molecules are shown in Table 3.

Table 3 Target sequences of anti-interferon effector molecules

In the anti-interferon effector molecule knock-in scheme in Tables 5 to 6 below, the target sequences of the anti-interferon effector molecules of each experimental group are the anti-interferon effector molecules constructed by using the target sequence 1 in Table 3. Those skilled in the art can understand that anti-interferon effector molecules constructed with other target sequences can also achieve the technical effects of the present invention, which all fall within the protection scope of the claims of the present invention.

1.7 General framework for immune-compatible molecules, shRNAs against interferon effector molecules, or shRNA-miRs

The general framework sequences of immunocompatible molecules, anti-interferon effector shRNAs or shRNA-miRs are shown below:

(1) The shRNA constitutive expression framework is:

GAGGGCCTATTTCCCATGATTCCTTCATATTTGCATATACGATACAAGGCTGTTAGAGAGATAATTGGAATTAATTTGACTGTAAACACAAAGATATTAGTACAAAATACGTGACGTAGAAAGTAATAATTTCTTGGGTAGTTTGCAGTTTTAAAATTATGTTTTAAAATGGACTATCATATGCTTACCGTAACTTGAAAGTATTTCGATTTCTTGGCTTTATATATCTTGTGGAAAGGACGCTAGCGCCACC(SEQ ID NO.164)N ₁ ...N ₂₁ TTCAAGAGA(SEQ IDNO.165)N ₂₂ ...N ₄₂ TTTTTT；

in:

_a . N1... _N21 is the shRNA target sequence of the corresponding gene, and _N22 ... _N42 is the reverse complementary sequence of the shRNA target sequence of the corresponding gene;

b. If the plasmid needs to express shRNA of multiple genes, each gene corresponds to a shRNA expression frame, and then they are seamlessly connected;

c. Constitutive shRNA plasmids with different resistance genes, only the resistance genes are different, and other sequences are the same;

d, N represent A, T, G, C bases;

e, SEQ ID NO.164 is the U6 promoter sequence;

f. SEQ ID NO. 165 is the stem-loop sequence.

(2) The shRNA-inducible expression framework is:

(SEQ ID NO. 166) N ₁ ... N ₂₁ TTCAAGAGA (SEQ ID NO. 165) N ₂₂ ... N ₄₂ TTTTTT;

in:

_a . N1... _N21 is the shRNA target sequence of the corresponding gene, and _N22 ... _N42 is the reverse complementary sequence of the shRNA target sequence of the corresponding gene;

b. If the plasmid needs to express shRNA of multiple genes, each gene corresponds to a shRNA expression frame, and then they are seamlessly connected;

c. Constitutive shRNA plasmids with different resistance genes, only the resistance genes are different, and other sequences are the same;

d, N represent A, T, G, C bases;

e, SEQ ID NO.166 is the H1 TO promoter sequence;

f. SEQ ID NO. 165 is the stem-loop sequence.

(3) The shRNA-miR constitutive or inducible expression framework is:

Obtained by replacing the target sequence in microRNA-30 with the shRNA-miR target sequence, the specific sequence is as follows:

GAGGCTTCAGTACTTTACAGAATCGTTGCCTGCACATCTTGGAAACACTTGCTGGGATTACTTCTTCAGGTTAACCCAACAGAAGGCTAAAGAAGGTATATTGCTGTTGACAGTGAGCG(SEQ ID NO.167)M ₁ N ₁ ...N ₂₁ TAGTGAAGCCACAGATGTA(SEQ ID NO.168)N ₂₂ ...N ₄₂ M ₂ TGCCTACTGCCTCGGACTTCAAGGGGCTACTTTAGGAGCAATTATCTTGTTTACTAAAACTGAATACCTTGCTATCTCTTTGATACATTTTTACAAAGCTGAATTAAAATGGTATAAAT(SEQ ID NO.169)；

in:

_a . N1... _N21 is the shRNA-miR target sequence of the corresponding gene, and _N22 ... _N42 is the reverse complementary sequence of the shRNA-miR target sequence of the corresponding gene;

b. If the plasmid needs to express shRNA-miR of multiple genes, each gene corresponds to a shRNA-miR expression frame, and then seamlessly connected;

c. Constitutive shRNA-miR plasmids with different resistance genes, only the resistance genes are different, and other sequences are the same;

d, M base represents A or C base, N represents A, T, G, C base;

e. If N ₁ is a G base, then M ₁ is an A base; otherwise, M ₁ is a C base;

_f . M1 base is complementary to _M2 base.

1.8 Gene editing system, gene editing method and testing method

1.8.1 Gene editing system

The gene editing technology of this patent adopts the CRISPR-Cas9 gene editing system. The Cas 9 protein used is Cas9(D10A), Cas 9(D10A) binds to sgRNA, sgRNA is responsible for specific recognition of the target sequence (genomic DNA), and then Cas 9(D10A) performs single-stranded cleavage of the target sequence. Genomic DNA double-strand break (DNA Double Strand Break, DSB), there must be two sets of Cas 9 (D10A)/sgRNA to cut the two strands of genomic DNA, and the cutting distance should not be too far. The advantages of Cas 9(D10A)/sgRNA protocol compared with Cas 9/sgRNA protocol are higher specificity and lower probability of off-target. The plasmids or Donor fragments used in this gene editing system are: Cas9 (D10A) plasmid, sgRNA clone plasmid, and Donor fragment, respectively.

(1) Cas9 (D10A) plasmid: a plasmid expressing Cas 9 (D10A) protein, which specifically cuts genomic DNA under the guidance of sgRNA.

(2) sgRNA plasmid: a plasmid expressing sgRNA, sgRNA (small guide RNA) is a guide RNA (guideRNA, gRNA), which is responsible for guiding the targeted cleavage of the expressed Cas 9 (D10A) protein in gene editing.

(3) Donor fragment: the two ends contain recombination arms, which are located on the left and right sides of the genomic DNA break position, and the middle contains the gene, fragment or expression element to be inserted. In the presence of Donor fragments, cells undergo a homologous recombination (HR) reaction at the site of genome breakage. If the Donor fragment is not added, the non-homologous end joining (NHEJ) reaction occurs at the genomic break site of the cell. The fragment was recovered by KI (Knock-in, the same below) vector plasmid digestion.

1.8.2 Constitutive and inducible plasmids

Constitutive plasmid: Donor fragment obtained from constitutive plasmid, after knocking in genomic DNA, the expression function of this fragment cannot be regulated.

Inducible plasmid: After the Donor fragment obtained from the inducible plasmid is knocked into the genomic DNA, the expression function of the fragment can be regulated by adding an inducer, which is equivalent to adding an on or off switch to the expression function.

1.8.3 Plasmid construction method

(1) Cas9 (D10A) plasmid: This plasmid no longer needs to be constructed, and is directly ordered from Addgene (Plasmid 41816, Addgene).

(2) sgRNA plasmid: The original blank plasmid was ordered from Addgene (Plasmid 41824, Addgene), and then the DNA sequence was entered on the website (URL: https://cctop.cos.uni-heidelberg.de) to design the target sequence, and finally the different The target sequences were put into blank sgRNA plasmids to complete the construction.

(3)KI Vector plasmid:

a. Acquisition of Amp(R)-pUC origin fragment: Design PCR primers, and use high-fidelity enzyme (Nanjing Novozymes, P505-d1) to amplify and recover the fragment by PCR with pUC18 plasmid as template ;

b. Acquisition of AAVS1 or eGSH recombination arm: extract the genomic DNA of human cells and design corresponding primers, and then use the human genomic DNA as a template to use a high-fidelity enzyme (Nanjing Novozymes, P505-d1) to pass the PCR method, Amplify and recover such fragments;

c. Acquisition of each plasmid element: Design the PCR amplification primers of each element, and then use the plasmid containing the element as a template and use a high-fidelity enzyme (Nanjing Novozyme, P505-d1) to separate each plasmid by PCR method. Elements are amplified and recovered;

d. Assemble into a complete plasmid: Use multi-fragment recombinase (Nanjing Novozymes, C113-02) to connect the fragments obtained in the previous steps to form a complete plasmid.

1.8.4 Gene editing process

1. Single-cell cloning operation steps of AAVS1 gene knock-in

(1) Electric transfer procedure:

Donor cell preparation: Human pluripotent stem cells.

Kit 1。Kit: Human Stem Cell

Kit 1.

Instrument: electroporator.

Medium: BioCISO.

Induction plasmids: Cas9D10A, sgRNA clone AAVS1-1, sgRNA clone AAVS1-2, AAVS1 neoVectoⅠ, AAVS1 neo VectorⅡ.

Note: The induction plasmids used for eGSH gene knock-in: Cas9D10A, sgRNA clone eGSH-1, sgRNA clone eGSH-2, eGSH-neo/eGSH-puro(donor) The donor plasmid here is compared with AAVS1, only the left and right recombination arms are different. All other components are the same. Since the gene editing process of eGSH is the same as that of AAVS1, it will not be repeated later.

(2) The electrotransformed human pluripotent stem cells were screened in double antibiotic medium containing G418 and puro.

(3) Screening and culturing single-cell clones to obtain single-cell clones.

2. Culture reagents for single-cell clones with AAVS1 gene knock-in

(1) Culture medium: BioCISO + 300μg/mL G418 + 0.5μg/mL puro (should be placed at room temperature in advance and placed in the dark for 30 to 60 minutes until it returns to room temperature. Note: BioCISO should not be placed at 37°C for Preheat to avoid reduced biomolecular activity.).

(2) Matrigel: hESC-grade Matrigel (before passage or resuscitation of cells, add the Matrigel working solution to the cell culture flask and shake well to ensure that the Matrigel completely covers the bottom of the culture flask, and the Matrigel cannot be placed anywhere before use. Dry. In order to ensure better adherence and survival of cells, Matrigel should be placed in a 37°C incubator for coating time: 1:100X Matrigel should not be less than 0.5 hours; 1:200X Matrigel should not be less than 2 hours.).

(3) Digestion solution: Use DPBS to dissolve EDTA to a final concentration of 0.5mM, pH 7.4 (Note: EDTA cannot be diluted with water, otherwise cells will die due to reduced osmotic pressure.).

(4) Cryopreservation solution: 60% BioCISO+30% ESCs grade FBS+10% DMSO (the cryopreservation solution is best prepared and used immediately).

3. Routine maintenance subculture process

(1) The best time for passage and passage ratio

a. The best time for passage: the overall confluence of cells reaches 80% to 90%;

b. The optimal ratio of passage: 1:4～1:7 passage, and the best confluence the next day should be maintained at 20%～30%.

(2) Passaging process

a. Aspirate and discard the Matrigel in the coated cell culture flask in advance, add an appropriate amount of medium (BioCISO+300μg/mL G418+0.5μg/mL puro), and put it into 37 ℃, 5% CO ₂ culture incubation in the box;

b. When the cells meet the requirements of passage, aspirate the medium supernatant, and add an appropriate amount of 0.5mM EDTA digestion solution to the cell flask dish;

c. Incubate the cells in a 37°C, 5% CO ₂ incubator for 5-10 minutes (digest until most cells shrink and become rounded but not floating under the microscope, gently pipette the cells to detach from the wall , suck the cell suspension into a centrifuge tube and centrifuge at 200g for 5 minutes;

d. After centrifugation, discard the supernatant, resuspend the cells with medium, gently pipette the cells several times to mix well, and then transfer the cells to a bottle prepared to be coated with Matrigel;

e. After the cells are transferred to the cell flask dish, shake them horizontally from front to back and left and right. After no abnormality is observed under the microscope, shake well and place them in a 37°C, 5% CO ₂ incubator for culture;

f. Observe the cell adherent survival state the next day, aspirate the medium and change the medium on time every day.

4. Cell cryopreservation

(1) According to the routine passaging procedure, digest the cells with 0.5mM EDTA until most of the cells shrink and become round but have not floated, gently pipet the cells, collect the cell suspension, centrifuge at 200g for 5 minutes, discard the supernatant, and add an appropriate amount of freezing solution Resuspend the cells and transfer the cells to a cryopreservation tube (it is recommended to freeze one tube at a confluence of 80% of the six-well plate, and the volume of the freezing solution is 0.5mL/tube);

(2) Place the cryovials in a programmed cooling box, and immediately put them at -80°C overnight (the temperature of the cryopreservation tube must be lowered by 1°C per minute);

(3) The cells were immediately transferred into liquid nitrogen the next day.

5. Cell recovery

(1) Prepare the Matrigel-coated cell flask dish in advance. Before resuscitating the cells, aspirate the Matrigel, add an appropriate amount of BioCISO to the cell flask dish, and incubate in a 37°C, 5% CO ₂ incubator;

(2) Quickly take out the cryopreservation tube from the liquid nitrogen, and immediately put it into a 37°C water bath and shake it quickly to thaw the cells quickly. After careful observation, stop shaking when the ice crystals completely disappear, and transfer the cells to a biological safety cabinet;

(3) Add 10 mL of DMEM/F12 (1:1) basal medium to a 15 mL centrifuge tube in advance, and equilibrate to room temperature. Use a Pasteur pipette to pipette 1 mL of DMEM/F12 (1:1) into the cryopreservation tube slowly, and mix gently. Homogenize, transfer the cell suspension to a prepared 15mL centrifuge tube containing DMEM/F12 (1:1), and centrifuge at 200g for 5 minutes;

(4) Carefully discard the supernatant, add an appropriate amount of BioCISO, mix the cells gently, and plant them in the prepared cell flask dish. , 5% CO ₂ incubator;

(5) Observe the cell adherent survival state the next day, and change the medium regularly every day. If the adherence is good, replace BioCISO with BioCISO+300μg/mL G418+0.5μg/mL puro.

1.8.5 AAVS1 gene knock-in detection method

1. Single-cell clone AAVS1 gene knock-in detection

(1) Description of AAVS1 gene knock-in detection

a. Purpose of the test: PCR detects the cells that have undergone gene knock-in treatment to test whether the cells are homozygous; since the two Donor fragments only have differences in the sequence of the resistance gene, it is necessary to determine whether the cells are homozygous (two Donor fragments). Chromosome knock-in Donor fragments of different resistance genes respectively), it is necessary to detect whether the genome of the cell contains Donor fragments of two resistance genes, only double-knock-in cells may be correct homozygotes;

b. Test method: first design a primer inside the Donor plasmid (non-recombination arm part), and then design another primer in the genome PPP1R12C (non-recombination arm part); if the Donor fragment can be inserted correctly in the genome, there will be a target band appears, otherwise no purposeful bands appear);

c. Test protocol The primer sequences and PCR protocol are shown in Table 4.

Table 4 Test protocol primer sequences and PCR protocol

2. The detection method of eGSH gene knock-in is the same as that of AAVS1 gene knock-in detection, and will not be described here.

1.8.6 Test methods for knock-in gene methods at safe genomic sites

(1) Test purpose: PCR detection of gene knock-in-treated cells to test whether the cells are homozygous. Since the two Donor fragments only have differences in the sequence of the resistance gene, to determine whether the cell is homozygous (two chromosomes knock-in the Donor fragments of different resistance genes respectively), it is necessary to detect whether the genome of the cell contains two genes. The Donor fragment of the resistance gene, only double knock-in cells may be correct homozygous.

(2) Test method: First design a primer inside the Donor plasmid (non-recombination arm part), and then design another primer in the genome (non-recombination arm part). If the Donor fragment can be inserted correctly in the genome, there will be a target band, otherwise no target band will appear.

1.9 Determination method of pluripotent stem cells expressing anti-B7-H4 antibody

Anti-B7-H4 antibodies expressed by pluripotent stem cells were tested by flow cytometry. The anti-B7-H4-expressing CHO cells were suspended in the culture supernatant of the anti-PD-1 antibody-expressing pluripotent stem cells, and incubated at 37°C for 30 minutes. The cells were washed twice with PBS and the FITC-labeled anti-B7-H4 fusion protein was added to the test tube and incubated at 37°C for 30 minutes. Flow cytometric analysis was performed using a flow cytometer. The binding of anti-B7-H4 antibodies expressed by pluripotent stem cells to human B7-H4 transfected CHO cells was measured based on the mean fluorescence intensity (MFI) of the staining. It can be shown that the anti-B7-H4 antibody expressed by the pluripotent stem cells expressing the B7-H4 blocker can block the function of inhibiting B7-H4.

1.10 ⁵¹ Cr release assay to detect the effect of anti-B7-H4 antibody on T cells killing tumor

(1) Preparation of effector cells:

T cell isolation: use Ficoll-hypaque density gradient centrifugation to isolate human peripheral blood mononuclear cells (PBMC), and then use Dynabeads ^TM CD3 (Invitrogen ^TM , Cat. No. 11151D) kit to isolate T cells. Cells were resuspended in RPMI1640 medium containing 10% FBS, counted by trypan blue staining, and concentrated to 1 x ¹⁰⁷ cells/mL.

(2) Preparation of target cells

Tumor (MC colon cancer) cells were digested and resuspended, cells were counted by trypan blue staining, and a cell suspension of 1×10 ⁷ cells/mL was prepared.

(3) ⁵¹ Cr release test

Tumor cells were first incubated with the medium supernatant of pluripotent stem cells expressing anti-B7-H4 antibody for 30 minutes, and then when contacted with T cells, T would attack the tumor cells and cause cell lysis and death. However, if the culture supernatant of pluripotent stem cells expressing anti-B7-H4 antibody is not incubated, tumor cells will not be recognized by T cells, and immune escape will occur. Therefore, by detecting the amount of ⁵¹ Cr in the medium, the ability of T cells to kill tumors can be reflected. The smaller the amount of ⁵¹ Cr released into the culture medium, the more likely the tumor cells to escape immune.

To quantitatively detect cell-mediated cytotoxicity, target cells were labeled with radioisotope ⁵¹ Cr, incubated with effector molecules or cells, and the cytotoxic activity was determined according to the number of ⁵¹ Cr radiation pulses (cpm) released by target cell lysis:

a. Label the target cells with 100 μCi (Ci, radioactivity unit) Na ⁵¹ CrO ₄ at 37°C for 120 min, shake once every 15 minutes, and then use the washing solution to centrifuge and wash 5 times after labeling, and finally resuspend in the culture solution medium, make up to 1×10 ⁶ cells/mL for later use;

b. Add target cells and T cells to a 96-well culture plate, add 100 μL of target cells (2.5×10 ³ ) and 100 μL of effector cells (E/T=1:2, 1:5, 1:10, E/T=1:2, 1:5, 1:10) to each well /T is the ratio of target cells to effector cells T), and set up natural release control wells (100μL target cells + 100uL medium) and maximum release wells (100μL target cells + 100uL 2% SDS); place at 37°C, 5% CO ₂ culture and incubate for 4h. After taking out, the supernatant of each well was sucked out with a pipette, centrifuged to take 100 μL of the supernatant, and the cpm value was measured with a gamma counter;

c. Result calculation: Calculate the natural release rate of ⁵¹ Cr and the activity of T cells according to the formula:

Note: Generally, the natural release rate of ⁵¹ Cr is required to be less than 10%.

1.11 Mice tumor treatment methods

In humanized NSG mice (The Jackson Laboratory (JAX)), 5×10 ⁶ tumor cells (MC colon cancer, NIC lung cancer, MM melanoma) cells were injected subcutaneously in the right axilla, and the tumors grew to 60 mm ³ 200 uL PBS (containing human immune cells and 1×10 ⁶ B7-H4 blocker-expressing pluripotent stem cell derivatives) were injected into the tail vein for tumor treatment, and only the group containing human immune cells was injected as a control group. After 20 days, the mice were sacrificed, and then the tumor size between the groups was compared and the statistical analysis of differences was performed.

2. Experimental protocol

The experimental protocol for knocking-in genes expressing B7-H4 blocker, one or more immune-compatible molecules, shRNA and/or miRNA processing complex-related genes, and anti-interferon effector molecules into safe sites in the genome of pluripotent stem cells is shown in the table below. 5-Table 6, where "+" indicates gene or nucleic acid sequence knock-in, and "-" indicates gene knock-out.

Table 5 Experimental protocol for constitutive expression

The selected plasmids and the specific knock-in positions are as follows:

General principles:

The anti-B7-H4 antibody is a secretory antibody, and its structure is: IL-2sig signal peptide (SEQ ID NO.183)+light chain (the end of the light chain sequence adds a stop codon TGA)+EMCV IRESwt (SEQ ID NO.178 ) + IL-2sig signal peptide + heavy chain (stop codon TGA is added to the end of the heavy chain sequence).

The anti-B7-H4 antibody sequence was placed in the position of MCS2 of the corresponding plasmid (the LC light chain and HC heavy chain of the antibody were added in front of the IL-2sig signal peptide, and the LC light chain and HC heavy chain sequences of the antibody were connected using EMCV IRESwt. , the sorting order is as follows: LC light chain, EMCV IRESwt, HC heavy chain), shRNA is put into the shRNA expression frame of the corresponding plasmid, shRNA-miR is put into the shRNA-miR expression frame of the corresponding plasmid, and other genes are put into the shRNA-miR expression frame of the corresponding plasmid. Location of MCS1. The maps of each plasmid are shown in Figures 1-11.

Note: sgRNA clone B2M plasmid contains sgRNA clone B2M-1 and sgRNA clone B2M-2 plasmids. The sgRNA clone CIITA plasmid contains the sgRNA clone CIITA-1 and sgRNA clone CIITA-2 plasmids.

(1) Group A1

The MCS2 of the AAVS1 KI Vector (shRNA, constitutive) plasmid was placed into the B7-H4 antibody sequence.

(2) A2 grouping

The MCS2 of the AAVS1 KI Vector (shRNA, constitutive) plasmid was placed into the B7-H4 antibody sequence. The shRNA expression framework is placed into the shRNA target sequence (seamlessly linked if multiple shRNAs are present). MCS1 was placed into the gene sequence (connected using EMCV IRESwt if multiple genes were present).

(3) A3 grouping

The MCS2 of the AAVS1 KI Vector (shRNA-miR, constitutive) plasmid was placed into the B7-H4 antibody sequence. The shRNA-miR expression framework is placed into the shRNA-miR target sequence (seamlessly linked if multiple shRNA-miRs are present). MCS1 was placed into the gene sequence (connected using EMCV IRESwt if multiple genes were present).

(4) A4 grouping

The MCS2 of the AAVS1 KI Vector (shRNA, constitutive) plasmid was put into the B7-H4 antibody sequence, the target sequence of the sgRNA cloneB2M plasmid was put into the sgRNA target sequence of B2M (SEQ ID NO.179 and SEQ ID NO.180), the sgRNA cloneCIITA plasmid The target sequence was placed into the sgRNA target sequence of CIITA (SEQ ID NO. 181 and SEQ ID NO. 182). MCS1 was placed into the gene sequence (connected using EMCV IRESwt if multiple genes were present).

(5) A5 grouping

The method of grouping with A2.

(6) A6 grouping

The method of grouping with A3.

Table 6 Inducible expression (immunocompatible and reversible) experimental protocol

(1) Group B1:

The MCS2 of the AAVS1 KI Vector (shRNA, inducible) plasmid was placed into the B7-H4 antibody sequence. The shRNA expression framework is placed into the shRNA target sequence (seamlessly linked if multiple shRNAs are present). MCS1 was placed into the gene sequence (connected using EMCV IRESwt if multiple genes were present).

(2) Group B2:

The MCS2 of the AAVS1 KI Vector (shRNA-miR, inducible) plasmid is placed into the B7-H4 antibody sequence, and the shRNA-miR expression framework is placed into the shRNA-miR target sequence (if there are multiple shRNA-miRs, they are seamlessly connected). MCS1 was placed into the gene sequence (connected using EMCV IRESwt if multiple genes were present).

(3) Group B3:

The method of grouping with B1.

(4) Group B4:

The method of grouping with B2.

3. Experimental results

3.1 Detection of blocking effect of anti-B7-H4 antibodies expressed by stem cells or their derivatives

The protocols of each experimental group in Table 5 and Table 6 were knocked into the genome safety site of MSCs cells, cultured at 37°C in a 0.5% CO ₂ incubator, the medium supernatant was collected, and the CHO cells expressing B7-H4 were resuspended and incubated at 37°C. Incubate for 30 minutes. The cells were washed twice with PBS and the FITC-labeled B7-H4 fusion protein was added to the test tube and incubated at 37°C for 30 minutes. Flow cytometric analysis was performed using a flow cytometer. The test results of each experimental group are shown in Table 7.

N (control) refers to untreated CHO cells expressing B7-H4, incubated at 37°C for 30 minutes, washed the cells twice with PBS and added FITC-labeled B7-H4 fusion protein to the test tube, incubated at 37°C for 30 minutes minute. The test results of each experimental group are shown in Table 7.

Table 7 Blocking effect of anti-B7-H4 antibodies expressed in each experimental group on B7-H4

It can be seen from the above table that the anti-B7-H4 antibody expressed by the pluripotent stem cells or derivatives thereof of the present invention can effectively bind to B7-H4. And its expression level is relatively constant in each group, so the anti-B7-H4 antibody expressed by pluripotent stem cell derivatives is not affected by cell differentiation morphology and other exogenous genes (immunocompatible transformation).

3.2 Antitumor effect of pluripotent stem cells or their derivatives expressing B7-H4 blocker

The protocols of each experimental group in Table 5 and Table 6 were knocked into the genomic safety site of MSCs cells to obtain cells expressing B7-H4 blocker. The anti-tumor effect was tested by ⁵¹ Cr release test, and the results are shown in Table 8.

Table 8 Effects of B7-H4 antibodies expressed in each experimental group on T cells killing tumor cells

grouping ⁵¹Cr release rate average (%) Deviation (±) Independent sample t-test (*p<0.01) N (control) 30.305 0.598 - A1 60.003 0.898 * A2 58.891 1.273 * A3 60.582 1.728 * A4 59.787 1.917 * A5 59.026 1.036 * A6 59.712 1.572 * B1 60.898 0.967 * B2 60.137 1.644 * B3 60.951 1.296 * B4 59.645 1.089 *

Note: N (control) group refers to cells that were not treated with the supernatant of the medium of the B7-H4 antibody-expressing pluripotent stem cells or their derivatives. Independent sample t-test (*p<0.01).

Through the above experiments, it can be proved that the stem cells or their derivatives expressing the B7-H4 blocker prepared by the present invention can effectively block B7-H4, activate T cells and play an anti-tumor effect.

3.3 Antitumor therapeutic effect of pluripotent stem cells or their derivatives expressing B7-H4 blocker

In the humanized NSG mouse tumor model, we injected hPSCs-derived derivatives (hPSCs-MSCs) capable of expressing B7-H4 antibody, and observed the effect of tumor therapy on MC colon cancer, NIC lung cancer, and MM melanoma. , and only the group containing human immune cells was injected as the control group. Note: In order to avoid the problem of immune compatibility, the immune cells and hPSCs-derived derivatives we used were all derived from the same human, and the immune compatibility protocol of B2M and CIITA gene knockout was adopted. The experimental results are shown in 9.

Table 9 Tumor therapeutic effect of pluripotent stem cells or derivatives thereof expressing B7-H4 antibody

Note: The control group refers to the NSG mouse tumor model that was not injected with B7-H4 antibody-expressing pluripotent stem cells or their derivatives.

Through the above experiments, it can be proved that the stem cells or their derivatives expressing the B7-H4 blocker prepared by the present invention can effectively block B7-H4 and play an anti-tumor effect.

3.4 Reversible expression test of immune-compatible molecular-inducible expression panel

Through the above examples, hPSCs or hPSCs-derived derivatives expressing B7-H4 blockers can effectively block B7-H4 and play an anti-tumor effect. We must also consider the immunocompatibility of hPSCs or hPSCs-derived derivatives. Therefore, we selected a suitable combination to test the immune compatibility.

Taking advantage of the low immunogenicity of MSCs, in a humanized NSG mouse tumor model, we injected hPSCs-derived immune-compatible MSCs that could express B7-H4 blocker (anti-B7-H4 antibody), and observed their Effect of tumor (MC colon cancer) therapy. Note: The immune cells and hPSCs-derived MSCs used are not from the same person.

The control group refers to the NSG mouse tumor model without MSCs injection.

The treatment of the Dox-added group was as follows: 0.5 mg/mL of Dox was added to the mouse diet, and the mice were fed, starting from the injection of the cells expressing the blocker, and used until the end of the experiment. The results are shown in Table 10.

Table 10 The reversible expression test results of the immune-compatible molecule-inducible expression group

The above experiments showed that MSCs (group 2) that only expressed the blocker had low immunogenicity and could exist in the allogene for a certain period of time, so they could exert a certain tumor therapeutic effect, while the MSCs that were immunocompatibly transformed (group 3) -11, including constitutive and reversible inducible immune compatibility), its immune compatibility effect is better, and it can exist in the body for a longer time (or can achieve long-term coexistence) than MSCs without immune compatibility modification. The group 5 is the B2M and CIITA gene knockout group, which completely eliminates the effects of HLA-I and HLA-II molecules, so its tumor treatment effect is the best. However, due to its constitutive immune-compatible modification (gene knock-in/knock-out), it cannot be cleared when the graft is mutated or not needed, so there is a group 8-15 protocol setting. In Groups 12-15, the Dox inducer (always used) was administered to the mice at the same time as the injection of the blocker-expressing cells into the mice. The existence time in vivo is comparable to that of MSCs without immunocompatibility modification, and its tumor treatment effect is also comparable to that of MSCs without immunocompatibility modification.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, The simplification should be equivalent replacement manners, which are all included in the protection scope of the present invention.

SEQUENCE LISTING

<110> Future Homo sapiens Regenerative Medicine Research Institute (Guangzhou) Co., Ltd.; Wang Linli

<120> A pluripotent stem cell expressing B7-H4 blocker or its derivative and application

<130>

<160> 183

<170> PatentIn version 3.5

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cagctgcagc tgcaggagag cggccccggc ctggtgaagc ccagcgagac cctgagcctg 60

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cagccccccg gcaagggcct ggagtggatc ggcaacatct actacagcgg cagcacctac 180

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ggcagctacc ccaactggtt cgacccctgg ggccagggca ccctggtgac cgtgagcagc 360

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ggcaccgccg ccctgggctg cctggtgaag gactacttcc ccgagcccgt gaccgtgagc 480

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ggcctgtaca gcctgagcag cgtggtgacc gtgcccagca gcagcctggg cacccagacc 600

tacatctgca acgtgaacca caagcccagc aacaccaagg tggacaagaa ggtggagccc 660

aagagctgcg acaagaccca cacctgcccc ccctgccccg cccccgagct gctgggcggc 720

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gaggtgacct gctgggtggt ggacgtgagc cacgaggacc ccgaggtgaa gttcaactgg 840

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gagtacaagt gcaaggtgag caacaaggcc ctgcccgccc ccatcgagaa gaccatcagc 1020

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ctggacagcg acggcagctt cttcctgtac agcaagctga ccgtggacaa gagcaggtgg 1260

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gagatcgtga tgacccagag ccccgccacc ctgagcgtga gccccggcga gagggccacc 60

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gggtctccag tatattcatc t 21

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gcctcctgat gcacatgtac t 21

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gggtctggtg ggcatcatta t 21

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gcatcattat tgggaccatc t 21

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gcacatggag gtgatggtgt t 21

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gcgtaagtct gagtgtcatt t 21

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gagtactgga acagccagaa g 21

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gctttcctgc ttggctctta t 21

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ggatgtggaa cccacagata c 21

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gatgtggaac ccacagatac a 21

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gtggaaccca cagatacaga g 21

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ggaacccaca gatacagaga g 21

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gagccaactg tattgcctat t 21

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agccaactgt attgcctatt t 21

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gccaactgta ttgcctattt g 21

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gggtagcaac tgtcaccttg a 21

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ggatttcgtg ttccagttta a 21

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gcatgtgcta cttcaccaac g 21

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gcgtcttgtg accagataca t 21

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gcttatgcct gcccagaatt c 21

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gcaggaaatc actgcagaat g 21

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<400> 80

gctcagtgca ttggccttag a 21

<210> 81

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<400> 81

ggtgagtgct gtgtaaataa g 21

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<400> 82

gacatatata gtgatccttg g 21

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<400> 83

ggaaagtcac atcgatcaag a 21

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<400> 84

gctcacagtc atcaattata g 21

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gccctgaaga cagaatgttc c 21

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gcggaccatg tgtcaactta t 21

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ggaccatgtg tcaacttatg c 21

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gcgtttgtac agacgcatag a 21

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<400> 89

ggctggctaa cattgctata t 21

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ggaccaggtc acatgtgaat a 21

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ggaaaggtct gaggatattg a 21

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ggcagattag gattccattc a 21

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<400> 94

gcctgatagg acccatattc c 21

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<400> 95

gcatccaata gacgtcattt g 21

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gcgtcactgg cacagatata a 21

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gctgtcacat aataagctaa g 21

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<400> 98

gctaaggaag acagtatata g 21

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<400> 100

ggagttgaag agcagagatt c 21

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<400> 101

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gcttctctga agtctcattg a 21

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gctgaacttc ttcatgtatg t 21

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gcctcatctc tttgttctaa a 21

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<400> 111

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<400> 112

ggacaaacat gcaaactata g 21

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<400> 113

gcagcaacca gctaccattc t 21

<210> 114

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<400> 114

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<210> 115

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<400> 117

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<210> 118

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<400> 118

gcctgtcaaa gagagagagc a 21

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<400> 119

gctcagcttc gtactgagtt c 21

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<400> 120

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<400> 121

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<400> 123

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<400> 124

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<210> 125

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<400> 125

ggatcagaag agaagccaac g 21

<210> 126

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<400> 126

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<210> 127

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<400> 127

gctctcttct ctggaactaa c 21

<210> 128

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<400> 128

gctagagtga ctccatctta a 21

<210> 129

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<400> 129

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<210> 130

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<400> 130

gcagaatatt taaggccata c 21

<210> 131

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<400> 131

gcccacttaa aggcagcatt a 21

<210> 132

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<400> 132

ggtcatcaat accactgtta a 21

<210> 133

<211> 21

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<400> 133

gcattcctcc ttctcctttc t 21

<210> 134

<211> 21

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<400> 134

ggaggaactt tgtgaacatt c 21

<210> 135

<211> 21

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<400> 135

gctgtaagaa ggatgctttc a 21

<210> 136

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<400> 136

gctgcaggca ggattgtttc a 21

<210> 137

<211> 21

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<400> 137

gcagttcgag gtcaagtttg a 21

<210> 138

<211> 21

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<400> 138

gccaattagc tgagaagaat t 21

<210> 139

<211> 21

<212> DNA

<213> human

<400> 139

gcaggtttac agtgtatatg t 21

<210> 140

<211> 21

<212> DNA

<213> human

<400> 140

gcctacagag actagagtag g 21

<210> 141

<211> 21

<212> DNA

<213> human

<400> 141

gcagttgggt accttccatt c 21

<210> 142

<211> 21

<212> DNA

<213> human

<400> 142

gcaactcagg tgcatgatac a 21

<210> 143

<211> 21

<212> DNA

<213> human

<400> 143

gcatggcgct ggtacgtaaa t 21

<210> 144

<211> 19

<212> DNA

<213> human

<400> 144

gcctcgagtt tgagagcta 19

<210> 145

<211> 19

<212> DNA

<213> human

<400> 145

agacattctg gatgagtta 19

<210> 146

<211> 19

<212> DNA

<213> human

<400> 146

gggtctgtta cccaaagaa 19

<210> 147

<211> 19

<212> DNA

<213> human

<400> 147

ggtctgttac ccaaagaat 19

<210> 148

<211> 19

<212> DNA

<213> human

<400> 148

ggaaggaagc ggacgctca 19

<210> 149

<211> 19

<212> DNA

<213> human

<400> 149

ggaggcagta cttctgata 19

<210> 150

<211> 19

<212> DNA

<213> human

<400> 150

cgctctagag ctcagctga 19

<210> 151

<211> 19

<212> DNA

<213> human

<400> 151

ccaccacctc aaccaataa 19

<210> 152

<211> 19

<212> DNA

<213> human

<400> 152

atttcaagaa gtcgatcaa 19

<210> 153

<211> 19

<212> DNA

<213> human

<400> 153

gaagatctga ttaccttca 19

<210> 154

<211> 21

<212> DNA

<213> human

<400> 154

ggacactggt tcaacacctg t 21

<210> 155

<211> 21

<212> DNA

<213> human

<400> 155

ggttcaacac ctgtgacttc a 21

<210> 156

<211> 21

<212> DNA

<213> human

<400> 156

acctgtgact tcatgtgtgc g 21

<210> 157

<211> 21

<212> DNA

<213> human

<400> 157

gctggacgtg accatcatgt a 21

<210> 158

<211> 21

<212> DNA

<213> human

<400> 158

ggacgtgacc atcatgtaca a 21

<210> 159

<211> 21

<212> DNA

<213> human

<400> 159

gacgtgacca tcatgtacaa g 21

<210> 160

<211> 21

<212> DNA

<213> human

<400> 160

acgtgaccat catgtacaag g 21

<210> 161

<211> 21

<212> DNA

<213> human

<400> 161

acgctatacc atctacctgg g 21

<210> 162

<211> 21

<212> DNA

<213> human

<400> 162

gcctctatga cgacatcgag t 21

<210> 163

<211> 21

<212> DNA

<213> human

<400> 163

gacatcgagt gcttccttat g 21

<210> 164

<211> 253

<212> DNA

<213> Artificial sequences

<400> 164

gagggcctat ttcccatgat tccttcatat ttgcatatac gatacaaggc tgttagagag 60

ataattggaa ttaatttgac tgtaaacaca aagatattag tacaaaatac gtgacgtaga 120

aagtaataat ttcttgggta gtttgcagtt ttaaaattat gttttaaaat ggactatcat 180

atgcttaccg taacttgaaa gtatttcgat ttcttggctt tatatatctt gtggaaagga 240

cgctagcgcc acc 253

<210> 165

<211> 9

<212> DNA

<213> Artificial sequences

<400> 165

ttcaagaga 9

<210> 166

<211> 686

<212> DNA

<213> Artificial sequences

<400> 166

gagggcctat ttcccatgat tccttcatat ttgcatatac gatacaaggc tgttagagag 60

ataattggaa ttaatttgac tgtaaacaca aagatattag tacaaaatac gtgacgtaga 120

aagtaataat ttcttgggta gtttgcagtt ttaaaattat gttttaaaat ggactatcat 180

atgcttaccg taacttgaaa gtatttcgat ttcttggctt tatatatctt gtggaaagga 240

ctttaccact ccctatcagt gatagagaaa agtgaaagtc gagtttacca ctccctatca 300

gtgatagaga aaagtgaaag tcgagtttac cactccctat cagtgataga gaaaagtgaa 360

agtcgagttt accactccct atcagtgata gagaaaagtg aaagtcgagt ttaccactcc 420

ctatcagtga tagagaaaag tgaaagtcga gtttaccact ccctatcagt gatagagaaa 480

agtgaaagtc gagtttacca ctccctatca gtgatagaga aaagtgaaag tcgagctcgg 540

tacccgggtc gaggtaggcg tgtacggtgg gaggcctata taagcagagc tcgtttagtg 600

aaccgtcaga tcgcctggag acgccatcca cgctgttttg acctccatag aagacaccgg 660

gaccgatcca gcctgctagc gccacc 686

<210> 167

<211> 119

<212> DNA

<213> Artificial sequences

<400> 167

gaggcttcag tactttacag aatcgttgcc tgcacatctt ggaaacactt gctgggatta 60

cttcttcagg ttaacccaac agaaggctaa agaaggtata ttgctgttga cagtgagcg 119

<210> 168

<211> 19

<212> DNA

<213> Artificial sequences

<400> 168

tagtgaagcc acagatgta 19

<210> 169

<211> 119

<212> DNA

<213> Artificial sequences

<400> 169

tgcctactgc ctcggacttc aaggggctac tttaggagca attatcttgt ttactaaaac 60

tgaatacctt gctatctctt tgatacattt ttacaaagct gaattaaaat ggtataaat 119

<210> 170

<211> 22

<212> DNA

<213> Artificial sequences

<400> 170

ccatagctca gtctggtcta tc 22

<210> 171

<211> 22

<212> DNA

<213> Artificial sequences

<400> 171

tcaggatgat ctggacgaag ag 22

<210> 172

<211> 20

<212> DNA

<213> Artificial sequences

<400> 172

ccggtcctgg actttgtctc 20

<210> 173

<211> 20

<212> DNA

<213> Artificial sequences

<400> 173

ctcgacatcg gcaaggtgtg 20

<210> 174

<211> 20

<212> DNA

<213> Artificial sequences

<400> 174

cgcattggag tcgctttaac 20

<210> 175

<211> 24

<212> DNA

<213> Artificial sequences

<400> 175

cgagctgcaa gaactcttcc tcac 24

<210> 176

<211> 23

<212> DNA

<213> Artificial sequences

<400> 176

cacggcactt acctgtgttc tgg 23

<210> 177

<211> 23

<212> DNA

<213> Artificial sequences

<400> 177

cagtacaggc atccctgtga aag 23

<210> 178

<211> 590

<212> DNA

<213> Artificial sequences

<400> 178

cccctctccc tccccccccc ctaacgttac tggccgaagc cgcttggaat aaggccggtg 60

tgcgtttgtc tatatgttat tttccaccat attgccgtct tttggcaatg tgagggcccg 120

gaaacctggc cctgtcttct tgacgagcat tcctaggggt ctttcccctc tcgccaaagg 180

aatgcaaggt ctgttgaatg tcgtgaagga agcagttcct ctggaagctt cttgaagaca 240

aacaacgtct gtagcgaccc tttgcaggca gcggaacccc ccacctggcg acaggtgcct 300

ctgcggccaa aagccacgtg tataagatac acctgcaaag gcggcacaac cccagtgcca 360

cgttgtgagt tggatagttg tggaaagagt caaatggctc tcctcaagcg tattcaacaa 420

ggggctgaag gatgcccaga aggtacccca ttgtatggga tctgatctgg ggcctcggtg 480

cacatgcttt acatgtgttt agtcgaggtt aaaaaaacgt ctaggccccc cgaaccacgg 540

ggacgtggtt ttcctttgaa aaacacgatg ataatatggc cacaaccatg 590

<210> 179

<211> 23

<212> DNA

<213> Artificial sequences

<400> 179

cgcgagcaca gctaaggcca cgg 23

<210> 180

<211> 23

<212> DNA

<213> Artificial sequences

<400> 180

actctctctt tctggcctgg agg 23

<210> 181

<211> 23

<212> DNA

<213> Artificial sequences

<400> 181

acccagcagg gcgtggagcc agg 23

<210> 182

<211> 23

<212> DNA

<213> Artificial sequences

<400> 182

gtcagagccc caaggtaaaa agg 23

<210> 183

<211> 60

<212> DNA

<213> Artificial sequences

<400> 183

atgtacagga tgcaactcct gtcttgcatt gcactaagtc ttgcacttgt cacgaattcg 60

Claims (20)

1. A pluripotent stem cell expressing a B7-H4 blocker, or a derivative thereof, wherein: the genome of the pluripotent stem cell or the derivative thereof is introduced with an expression sequence of a B7-H4 blocker, and the B7-H4 blocker is an anti-B7-H4 antibody.

2. The pluripotent stem cell or derivative thereof according to claim 1, wherein: the B2M and/or CIITA gene of the pluripotent stem cell or the derivative thereof is knocked out.

3. The pluripotent stem cell or derivative thereof according to claim 1, wherein: the genome of the pluripotent stem cell or the derivative thereof is further introduced with one or more immune compatible molecule expression sequences for regulating the expression of genes associated with an immune response in the pluripotent stem cell or the derivative thereof.

4. The pluripotent stem cell or derivative thereof according to claim 3, wherein: the genes associated with the immune response include:

(1) major histocompatibility complex genes including at least one of HLA-A, HLA-B, HLA-C, HLA-DRA, HLA-DRB1, HLA-DRB3, HLA-DRB4, HLA-DRB5, HLA-DQA1, HLA-DQB1, HLA-DPA1 and HLA-DPB 1;

(2) major histocompatibility complex-associated genes including at least one of B2M and CIITA.

5. The pluripotent stem cell or derivative thereof according to claim 3, wherein: the immune-compatible molecule includes any one or more of:

(1) immune tolerance related genes including CD47 or HLA-G;

(2) HLA-C molecules, including HLA-C multiple alleles of which the proportion in the population is over 90 percent in total, or fusion protein genes consisting of the HLA-C multiple alleles of which the proportion is over 90 percent and B2M;

(3) shRNA and/or shRNA-miR of major histocompatibility complex genes including at least one of HLA-A, HLA-B, HLA-C, HLA-DRA, HLA-DRB1, HLA-DRB3, HLA-DRB4, HLA-DRB5, HLA-DQA1, HLA-DQB1, HLA-DPA1 and HLA-DPB 1;

(4) shRNA and/or shRNA-miR of a major histocompatibility complex-associated gene that includes at least one of B2M and CIITA.

6. The pluripotent stem cell or derivative thereof according to claim 5, wherein:

the target sequence of the shRNA and/or shRNA-miR of B2M is at least one of SEQ ID NO. 3-SEQ ID NO. 5;

the target sequence of the shRNA and/or shRNA-miR of the CIITA is at least one of SEQ ID NO. 6-SEQ ID NO. 15;

the target sequence of the shRNA and/or shRNA-miR of the HLA-A is at least one of SEQ ID NO. 16-SEQ ID NO. 18;

the target sequence of the shRNA and/or shRNA-miR of the HLA-B is at least one of SEQ ID NO. 19-SEQ ID NO. 24;

the target sequence of the shRNA and/or shRNA-miR of the HLA-C is at least one of SEQ ID NO. 25-SEQ ID NO. 30;

the target sequence of the shRNA and/or shRNA-miR of the HLA-DRA is at least one of SEQ ID NO. 31-SEQ ID NO. 40;

the target sequence of the shRNA and/or shRNA-miR of the HLA-DRB1 is at least one of SEQ ID NO. 41-SEQ ID NO. 45;

the target sequence of the shRNA and/or shRNA-miR of the HLA-DRB3 is at least one of SEQ ID NO. 46-SEQ ID NO. 47;

the target sequence of the shRNA and/or shRNA-miR of the HLA-DRB4 is at least one of SEQ ID NO. 48-SEQ ID NO. 57;

the target sequence of the shRNA and/or shRNA-miR of the HLA-DRB5 is at least one of SEQ ID NO. 58-SEQ ID NO. 66;

the target sequence of the shRNA and/or shRNA-miR of the HLA-DQA1 is at least one of SEQ ID NO. 67-SEQ ID NO. 73;

the target sequence of the shRNA and/or shRNA-miR of the HLA-DQB1 is at least one of SEQ ID NO. 74-SEQ ID NO. 83;

the target sequence of the shRNA and/or shRNA-miR of the HLA-DPA1 is at least one of SEQ ID NO. 84-SEQ ID NO. 93;

the target sequence of the shRNA and/or shRNA-miR of the HLA-DPB1 is at least one of SEQ ID NO. 94-SEQ ID NO. 103.

7. The pluripotent stem cell or derivative thereof according to claim 3, wherein: shRNA and/or miRNA processing complex related genes and/or anti-interferon effector molecules are also introduced into the genome of the pluripotent stem cell or the derivative thereof.

8. The pluripotent stem cell or derivative thereof according to claim 7, wherein: the shRNA and/or miRNA processing complex related gene comprises at least one of Drosha, Ago1, Ago2, Dicer1, Exportin-5, TRBP (TARBP2), PACT (PRKRA) and DGCR 8; the anti-interferon effector molecule is shRNA and/or shRNA-miR of at least one of PKR, 2-5As, IRF-3 and IRF-7.

9. The pluripotent stem cell or derivative thereof according to claim 8, wherein:

the target sequence of the shRNA and/or shRNA-miR of the PKR is at least one of SEQ ID NO. 104-SEQ ID NO. 113;

the target sequence of the shRNA and/or shRNA-miR of the 2-5As is at least one of SEQ ID NO. 114-SEQ ID NO. 143;

the target sequence of the shRNA and/or shRNA-miR of the IRF-3 is at least one of SEQ ID NO. 144-SEQ ID NO. 153;

the target sequence of the shRNA and/or shRNA-miR of the IRF-7 is at least one of SEQ ID NO. 154-SEQ ID NO. 163.

10. The pluripotent stem cell or the derivative thereof according to claim 6 or 9, wherein: the expression frameworks of the major histocompatibility complex gene, the major histocompatibility complex related gene, PKR, 2-5As, the shRNA and/or shRNA-miR of IRF-3 or IRF-7 are As follows:

(1) shRNA expression framework: 5 'to 3' sequentially comprises the shRNA target sequence of claim 6 or 9, a stem-loop sequence, a reverse complement of the shRNA target sequence of claim 6 or 9, and Poly T; the two reverse complementary target sequences are separated by a middle stem-loop sequence to form a hairpin structure, and finally Poly T is connected to be used as a transcription terminator of RNA polymerase III;

(2) shRNA-miR expression framework: the shRNA-miR target sequence of claim 6 or 9 is used for replacing a target sequence in microRNA-30 or microRNA-155.

11. The pluripotent stem cell or derivative thereof of claim 10, wherein: the length of a stem-loop sequence in the shRNA expression frame is 3-9 bases; the poly T is 5-6 bases in length.

12. The pluripotent stem cell or the derivative thereof according to claim 3 or 7, wherein: an inducible gene expression system is also introduced into the genome of the pluripotent stem cell or the derivative thereof.

13. The pluripotent stem cell or derivative thereof of claim 12, wherein: the inducible gene expression system is at least one of a Tet-Off system and a dimer inducible expression system.

14. The pluripotent stem cell or derivative thereof of claim 12, wherein:

the introduction of the B7-H4 blocker expression sequence, the expression sequence of immune compatible molecules, shRNA and/or miRNA processing complex related genes, anti-interferon effector molecules and inducible gene expression system adopts a method of viral vector interference, non-viral vector transfection or gene editing.

15. The pluripotent stem cell or derivative thereof of claim 14, wherein:

the introduction sites of the B7-H4 blocker expression sequence, the immune compatible molecule expression sequence, shRNA and/or miRNA processing complex related genes, the anti-interferon effector molecule and the inducible gene expression system are genome safety sites of the pluripotent stem cells or derivatives thereof.

16. The pluripotent stem cell or derivative thereof of claim 15, wherein: the genome safe site comprises one or more of an AAVS1 safe site, an eGSH safe site and an H11 safe site.

17. The pluripotent stem cell or the derivative thereof according to any one of claims 1 to 9, 11 and 13 to 16, wherein: the pluripotent stem cells comprise embryonic stem cells, embryonic germ cells, embryonic cancer cells, or induced pluripotent stem cells;

the pluripotent stem cell derivative includes an adult stem cell, each germ layer cell or tissue into which the pluripotent stem cell is differentiated;

the adult stem cells include mesenchymal stem cells or neural stem cells.

18. The pluripotent stem cell or derivative thereof of claim 17, wherein: the heavy chain sequence of the anti-B7-H4 antibody is shown as SEQ ID NO.1, and the light chain sequence is shown as SEQ ID NO. 2.

19. Use of the pluripotent stem cell or derivative thereof of any one of claims 1 to 18 for the preparation of a medicament for treating a B7-H4 high-expression tumor.

20. A formulation, characterized by: comprising the pluripotent stem cell of any one of claims 1 to 18 or a derivative thereof.

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