CN117866107A

CN117866107A - Chimeric antigen receptor T cell targeting CD5 molecule and anti-tumor application thereof

Info

Publication number: CN117866107A
Application number: CN202311763397.5A
Authority: CN
Inventors: 张继帅; 栗红建; 苏红昌; 祖璎玲; 罗燕平; 陆秋湄
Original assignee: Shenzhen Prijin Biopharmaceutical Co ltd
Current assignee: Shenzhen Prijin Biopharmaceutical Co ltd
Priority date: 2023-12-20
Filing date: 2023-12-20
Publication date: 2024-04-12

Abstract

The invention belongs to the technical field of biological medicines, and particularly relates to a chimeric antigen receptor T cell targeting a CD5 molecule and an anti-tumor application thereof. The chimeric antigen receptor comprises a 12C single domain antibody; the amino acid sequence of the 12C single domain antibody is shown as SEQ ID NO. 1; the chimeric antigen receptor targeting the CD5 molecule further comprises a signal peptide, an extracellular region, a transmembrane region, a cytoplasmic region, a self-cleaving region, and a retention domain. The chimeric antigen receptor can effectively block the expression of CD5 on T cells and prevent the suicide phenomenon of targeted CD5CAR-T cells; CD5CAR-T cells have significant specific killing of CCRF-CEM cells and the IFN- γ secretion levels are significantly increased after killing of CCRF-CEM cells; the CD5CAR-T cells can effectively remove CD5 positive tumor cells, and have remarkable in-vivo anti-tumor effect.

Description

Chimeric antigen receptor T cell targeting CD5 molecule and anti-tumor application thereof

Technical Field

The invention belongs to the technical field of biological medicines, and particularly relates to a chimeric antigen receptor T cell targeting a CD5 molecule and an anti-tumor application thereof.

Background

T cell malignancies are a broad group of heterogeneous diseases with poor prognosis in both pediatric and adult patients (Sehn LH, soulier J.Instroreduction to the review series on T-cell malignancies [ J ]. Blood,2017, 129:1059-60). T-cell acute lymphoblastic leukemia (T-ALL) is a highly heterogeneous hematological malignancy, accounting for 25% of adult acute lymphoblastic leukemia cases and 15% of pediatric acute lymphoblastic leukemia cases. At present, the treatment means of T cell malignant tumor mainly comprise chemotherapy, hematopoietic stem cell transplantation, targeted therapy and the like. Compared with B-cell malignant tumor, the first-line chemotherapy of T-cell malignant tumor only achieves limited clinical response, and hematopoietic stem cell transplantation is often accompanied with complications such as graft versus host disease (graft versus host disease, GVHD) and infection as a radical treatment means, so that the problems of limited curative effect, high recurrence rate, high GVHD incidence and the like exist in clinical application, and poor prognosis is often caused (MaH, abdul-Hay M.T-cell lymphomas, a challenging disease: types, diseases, and future [ J ]. Int J Clin Oncol,2017, 22:18-51).

In recent years, CAR-T therapy has achieved great success in the field of B-cell malignancy therapy, but its study and application in T-cell malignancy is very limited. CAR-T therapy against T cell malignancies remains a number of challenges, including mainly the risk that expression of target antigen on the surface of CAR-T cells results in CAR-T cell self-phase killing, contamination of malignant T cells when autologous CAR-T is prepared (M.Alcantara, M.Tesio, C.H.June, R.Houot, CAR T-cells for T-cell malignancies: challenges in distinguishing between therapeutic, normal, and neoplastic T-cells, leukemia 32 (11) (2018) 2307-2315) and allo-infusion of time-shifted plant anti-host disease (GVHD).

Currently, the targets involved in immunotherapy of T cell malignancies are mainly CD3, CD4, CD5 and CD7.CD5 is a pan-T cell marker that is ubiquitously overexpressed in most T cell malignancies (CASALIP, BURASTERO S E, NAKAMURA M, et al human lymphocytes making rheumatoid factor and antibody to ssDNA belong to Leu1+Bcell subset [ J ]. Science,1987,236 (4797):77), while being expressed on a portion of B cell malignancy surfaces, such as chronic lymphocytic leukemia (chronic lymphocytic leukemia, CLL), mantle cell lymphoma (mantle cell lymphoma, MCL). The expression of normal cell CD5 is limited to thymocytes, peripheral T cells and a small subset of B lymphocytes, called B1 cells (FREITAS C M T, JOHNSON D K, WEBER K S.T Cell Calcium Signaling Regulation by the Co Receptor CD [ J ]. Int J Mol Sci,2018,19 (5):) and CD5 molecules are not expressed on the surface of hematopoietic stem cells. Thus, the CD5 molecule is expected to become an ideal target for T cell malignancy. However, the targeted treatment of T cell acute lymphoblastic leukemia with CD5CAR-T cells still faces significant problems, because both normal effector T cells and T cell tumors express CD5 antigen, resulting in the self-phase killing of CD5CAR-T cells, which is difficult to produce successfully in vitro. Therefore, there is a need to develop a chimeric antigen receptor that can effectively block the expression of CD5 on T cells, prevent the suicide phenomenon of CD5CAR-T cell targeting, and improve the efficacy and persistence of CD 5-targeted CAR-T cell therapies for treating T cell malignancies.

Disclosure of Invention

In order to solve the above problems, the present invention provides a chimeric antigen receptor targeting CD5 molecule, which comprises a 12C single domain antibody; the chimeric antigen receptor targeting the CD5 molecule further comprises a signal peptide, a hinge region, a transmembrane region, a cytoplasmic region, a self-cleaving region, and a retention domain.

In one aspect, the invention provides a chimeric antigen receptor that targets a CD5 molecule, said chimeric antigen receptor that targets a CD5 molecule comprising a 12C single domain antibody; the 12C single domain antibody comprises a heavy chain variable region CDR1, a CDR2 and a CDR3; the amino acid sequences of the CDR1, the CDR2 and the CDR3 are shown as SEQ ID NO.15-SEQ ID NO. 17.

Specifically, the amino acid sequence of the 12C single domain antibody is SEQ ID NO.1 or a sequence with 85% homology with SEQ ID NO.1.

Preferably, the amino acid sequence of the 12C single domain antibody is SEQ ID NO.1 or a sequence with 90% homology with SEQ ID NO.1.

Further preferably, the amino acid sequence of the 12C single domain antibody is SEQ ID NO.1 or a sequence having 95% homology with SEQ ID NO.1.

Further preferably, the amino acid sequence of the 12C single domain antibody is SEQ ID NO.1 or a sequence having 98% homology with SEQ ID NO.1.

Still more preferably, the amino acid sequence of the 12C single domain antibody is SEQ ID NO.1.

Specifically, the chimeric antigen receptor targeting the CD5 molecule further comprises a signal peptide, an extracellular region, a transmembrane region, and/or a cytoplasmic region.

Further specifically, the chimeric antigen receptor targeting CD5 molecule further includes, but is not limited to: self-shearing zones and/or retention domains.

Specifically, the chimeric antigen receptor targeting the CD5 molecule is obtained by sequentially connecting the following modules in series: signal peptide of CD8 molecule, 12C single domain antibody, CD8 finger+tm region, 4-1BB cytoplasmic region, cytoplasmic region of CD3 zeta molecule, T2A self-cleaving region, 12C single domain antibody, ER retention domain.

More specifically, the amino acid sequence of the signal peptide of the CD8 molecule is shown as SEQ ID NO. 2; the amino acid sequence of the CD8 finger+TM region is shown as SEQ ID NO. 3; the amino acid sequence of the 4-1BB cytoplasmic domain is shown as SEQ ID NO. 4; the amino acid sequence of the cytoplasmic region of the CD3 zeta molecule is shown as SEQ ID NO. 5; the amino acid sequence of the T2A self-shearing region is shown as SEQ ID NO. 6; the amino acid sequence of the ER retention domain is shown in SEQ ID NO. 7.

Specifically, the amino acid sequence of the chimeric antigen receptor targeting the CD5 molecule is shown as SEQ ID NO.9.

In yet another aspect, the invention provides a nucleic acid encoding the chimeric antigen receptor described above.

Specifically, the sequence of the nucleic acid is shown as SEQ ID NO.8 or a sequence with more than 80% of sequence homology with SEQ ID NO. 8.

In yet another aspect, the invention provides a modified T cell comprising, expressing and/or secreting the chimeric antigen receptor described above.

In particular, the T cell may be a CAR-T cell.

In yet another aspect, the invention provides a cell culture of the aforementioned T cells comprising a chimeric antigen receptor that targets a CD5 molecule.

In yet another aspect, the invention provides a medicament of the foregoing T cell or cell culture.

Specifically, the medicine also comprises pharmaceutically acceptable auxiliary materials.

Preferably, the pharmaceutically acceptable auxiliary materials are selected from polysorbate, histidine, sucrose, arginine, sodium chloride, methionine, acetate, trehalose, proline, sorbitol, sodium phosphate, poloxamer 188, ethylenediamine tetraacetic acid, citric acid, mannitol, glutamate, glycine, sodium citrate, sodium succinate and/or lactic acid.

In yet another aspect, the invention provides the use of the chimeric antigen receptor or T cell or cell culture described above for the preparation of an anti-tumor agent.

In particular, the neoplasm includes a T cell malignancy.

In a further aspect, the invention provides the use of a chimeric antigen receptor or a T cell or cell culture as described above for the preparation of a medicament for the prophylaxis and/or treatment of an immune disorder.

In particular, the applications include, but are not limited to: rheumatic arthritis, systemic lupus erythematosus, type I diabetes, and/or myasthenia gravis.

In yet another aspect, the invention provides a CD5 assay kit comprising the chimeric antigen receptor or T cell or cell culture described above.

Specifically, the kit also comprises a solid phase carrier, a detection label, a detection substrate and/or a buffer solution.

Further specifically, the solid support may be a material having affinity that immobilizes the specific antibody on the surface.

The detection label may be an enzyme label, which is an enzyme capable of binding to an antibody, for detecting binding of the antibody to an antigen.

The detection substrate may be a reaction product of an enzyme label capable of producing a measurable signal under enzymatic catalysis.

In yet another aspect, the invention provides a method for detecting CD5 comprising the chimeric antigen receptor or the T cell or the cell culture or the kit, wherein the method is a non-disease diagnosis or treatment method.

The invention has the technical effects that:

(1) The 12C-ER can effectively block the expression of CD5 on T cells and prevent the suicide phenomenon of targeted CD5CAR-T cells;

(2) Under the condition of different effective target ratios, the CD5CAR-T cells have obvious specific killing on CCRF-CEM cells;

(3) IFN-gamma secretion levels were significantly increased after 12 C.b. CAR-T killing of CCRF-CEM cells.

(4) The CD5CAR-T cells can effectively remove CD5 positive tumor cells, and have remarkable in-vivo anti-tumor effect.

Drawings

FIG. 1 is a schematic diagram of CD5-CART structure with CD5 blocking; wherein CD8 SP represents a signal peptide of a CD8 molecule; 12C sdAb represents a single domain antibody sequence that targets CD 5; CD8 finger+TM represents the extracellular region, transmembrane region column of the CD8 molecule; 4-1BB represents a 4-1BB cytoplasmic domain sequence; cd3ζ represents the cytoplasmic sequence of the cd3ζ molecule; T2A represents a self-cleaving sequence; ER represents ER retention domain sequences.

FIG. 2 is a map of lentiviral vector Pre-Lenti-EF1-CAR V2 Wpmut.

FIG. 3 is a map of packaging plasmid pMDLg-pRRE-K.

FIG. 4 is a map of the packaging plasmid pRsv-rev-kana-V2.

FIG. 5 is a map of the envelope plasmid pMD2. G-K.

FIG. 6 is a flow assay for CD5CAR-T CAR positive rate of CD5 expression block and CD5 molecule expression on cell membrane; wherein, graph a is 12c.b CAR-T cell CAR positive rate is close to 100%; panel B shows that 12CER effectively blocks CD5 expression on T cells, whereas the positive rate of CD5 on the surface of T cells without the transfected CD5 blocking virus is 99.5%.

FIG. 7 is cytotoxicity of CD5CAR-T cells with blocked CD5 expression on CD 5-positive acute lymphoblastic leukemia cells (CCRF-CEM).

FIG. 8 shows cytokine IFN-gamma secretion following incubation of CD5CAR-T with CCRF-CEM cells with blocked CD5 expression.

Figure 9 is a graph of the results of in vivo tumor killing experiments with CD5CAR-T cells with blocked CD5 expression.

Detailed Description

The present invention will be described in further detail with reference to the following examples, which are not intended to limit the present invention, but are merely illustrative of the present invention. The experimental methods used in the following examples are not specifically described, but the experimental methods in which specific conditions are not specified in the examples are generally carried out under conventional conditions, and the materials, reagents, etc. used in the following examples are commercially available unless otherwise specified.

EXAMPLE 1 construction of CD5-CART vector with CD5 molecular blocking

The embodiment constructs a CAR lentiviral vector with Intrablock CD5 expression blocking function and targeting CD5, the structure is shown in figure 1, a 12C single domain antibody is taken as an antigen recognition region, a CD8 hinge region and CD8 transmembrane region sequence, a 4-1BB cytoplasmic region sequence and an intracellular signal molecule CD3 zeta sequence are combined, a CD5 single domain antibody sequence is connected through T2A, and an ER retention domain is connected, so that the CAR structure of targeting CD5 of T cells is named as 12C.b CAR. The lentiviral vector Pre-Lenti-EF1-CAR V2Wpmut and 12C.b CAR genes are subjected to enzyme digestion, connection, transformation, cloning, plasmid extraction and sequencing, so that the lentiviral vector Pre-Lenti-EF1-12CER-CAR V2WPmut with the correct sequence is obtained. The nucleotide sequence of 12C.b CAR is SEQ ID NO.8, and the corresponding amino acid sequence is SEQ ID NO.9.

The preparation method of lentiviral vector Pre-Lenti-EF1-CAR V2Wpmut (shuttle plasmid) is as follows:

(1) The 5'LTR of the shuttle plasmid pRRLSIN.cPPT.PGK-GFP.WPRE (http:// n2 t.net/adedge: 12252) is taken as an RSV promoter, and the promoter of the 5' LTR is changed from RSV to CMV, so that the efficient transcription of the viral genome sequence is facilitated; the 3' LTR original plasmid has removed the U3 region (3 ' LTR. DELTA.U3), has been designed for self-inactivation (SIN), and the 3' LTR sequence is unchanged.

(2) The hGGK promoter driving the expression of exogenous transgene is replaced by EF1 promoter, EGFP gene is replaced by polyclonal sequence (SEQ ID NO. 10);

(3) The ampicillin resistance gene was replaced with a kana resistance gene derived from pUC57-Kan (GenBank: LT 671993.1) plasmid;

(4) The WPRE element of pRRLSIN.cPPT.PGK-GFP.WPRE was modified so that truncated X protein was not expressed. The method comprises the following steps: within the sequence of the WPRE wild-type element, the promoter driving the transcription of protein X was deleted, the a of the initiation codon ATG was changed to T, and the new sequence was named WPREmut.

The modified shuttle plasmid is named as Pre-Lenti-EF1-CAR V2Wpmut, and the sequence is shown in SEQ ID NO. 11. The shuttle plasmid map is shown in FIG. 2, annotated in the map is shown in Table 1 below.

TABLE 1 shuttle plasmid Pre-Lenti-EF1-CAR V2WPmut elements annotation

EXAMPLE 2 lentiviral packaging

2.1 preparation of packaging plasmid pMDLg-pRRE-K

The packaging plasmid is derived from a plasmid pMDLg-pRRE, is initially constructed by Dier Trono Lab, is stored in Addgene (www.addgene.org/12251 /), has ampicillin resistance in a primary sequence, and is replaced by a kana resistance gene of a pET-28 (a) plasmid; the modified packaging plasmid is named pMDLg-pRRE-K, and the sequence is shown in SEQ ID NO. 12. The map of packaging plasmid pMDLg-pRRE-K is shown in FIG. 3 and the annotation is shown in Table 2.

TABLE 2

Element name	Functional area
		CMV promoter	Human cytomegalovirus promoter
β-globin intron	Human beta globulin truncated intron fragment
		HIV-1gag	Encoding gag protein
HIV-1pol	Encoding pol proteins
		RRE	Rev protein response element of HIV-1
β-globin poly(A)	Human beta-globulin polyadenylation signal
		Ori	ColE1/pMB1/pBR322 high copy replication origin
KanR	Kanamycin resistance gene

2.2 preparation of packaging plasmid pRsv-rev-kana-V2

The packaging plasmid is derived from plasmid pRSV-rev, is initially constructed by Dier Trono Lab, is stored in Addgene (www.addgene.org/12253 /), has ampicillin resistance in the original sequence, and is replaced by a kana resistance gene of pUC57-Kan (GenBank: LT 671993.1) plasmid; the above modified packaging plasmid was designated pRsv-rev-kana-V2 and the sequence shown in SEQ ID No. 13. The map of the packaging plasmid pRsv-rev-kana-V2 is shown in FIG. 4 and annotated as Table 3 below.

TABLE 3 Table 3

Element name	Functional area
		RSV promoter	RSV promoters
Rev	Viral gene expression modulators
		Ori	ColE1/pMB1/pBR322 high copy replication origin
KanR	Kanamycin resistance gene

2.3 preparation of the envelope plasmid pMD2.G-K

(1) The envelope plasmid pMD2.G, originally constructed from Dier Trono Lab, was stored in Addgene, (https:// www.addgene.org/12259 /). Based on its sequence and backbone, replacing its ampicillin resistance gene with the kana resistance gene of pET-28 (a) plasmid;

(2) The modified envelope plasmid is named pMD2.G-K, and the sequence is shown as SEQ ID NO. 14.

(3) The map of the envelope plasmid is shown in FIG. 5, and the annotation is shown in Table 4 below.

TABLE 4 Table 4

Element name	Functional area
		CMV enhancer	Human cytomegalovirus enhancer
CMV promoter	Human cytomegalovirus promoter
		β-globin intron	Human beta globulin truncated intron fragment
VSV-G	Vesicular stomatitis virus G glycoprotein
		β-globin poly(A)	Human beta-globulin polyadenylation signal
Ori	ColE1/pMB1/pBR322 high copy replication origin
		KanR	Kanamycin resistance gene

2.4 preparation of lentiviruses

And adopting a three-generation vector and four-plasmid system for packaging. The Pre-Lenti-EF1-12C-ER-CAR V2WPmut shuttle plasmid was mixed with the packaging plasmid pMDLg-pRRE-K, the envelope plasmid pMD2.G-K, the packaging plasmid pRsv-rev-kana-V2 in a ratio of 7:5:3:5, and the mixture of the above four plasmids was added to a tube containing 293TS basal medium. According to the plasmid: PEIpro = 1:2 ratio to another tube. After the two tubes are incubated at room temperature for 5min, the mixed solution containing PEIpro is slowly added into the mixed solution containing DNA, the centrifuge tube is gently rocked to mix uniformly, and the tubes are incubated at room temperature for 15min. The transfection mixture was then added drop-wise to a 293TS (ATCC, cat# CRL-3216) cell suspension. After 48 hours, collecting culture medium supernatant to obtain slow virus crude liquid. Then, lentivirus was concentrated, and the virus was stored at 80℃after split charging. Transduction titers of lentiviruses were determined based on flow cytometry.

The detection of transduction titres comprises the following steps:

the lentivirus crude venom was serially diluted to infect 293T cells, and after about 70h of infection, the sample CAR positive rate was detected using flow cytometry, transduction titer (TU/mL) =dilution fold x sample positive rate x cell amount/virus loading (mL). Transduction titres 4.21×10 ⁷ TU/mL。

Example 3 preparation of CD5CAR-T cells with blocked CD5 expression

Peripheral blood was collected from healthy volunteers and purified using Miltenyi CD3 Regent to obtain cd3+ T cells. Cells were grown in TexMACS GMP Medium (5% serum replacement) medium and T cells were activated using the transact CD3/CD28 reagent (1:100) and IL-2 (100 IU/mL). After 24 hours of T cell activation, the cells were infected with lentiviruses.

Example 4CD5 expression blocked CD5CAR-T CAR Positive Rate and expression of CD5 molecules on cell membranes

Primary T cells were transduced by lentiviral vectors and the CD5CAR-T CAR positive rate and CD5 molecule expression on the cell membrane were detected using flow-through. The results are shown in fig. 6, which demonstrate that the 12c.b CAR-T cell CAR positive rate is close to 100%, (a in fig. 6). 12C-ER (12C single domain antibody sequence and linked to ER retention domain) effectively blocked CD5 expression on T cells, whereas the positive rate of CD5 on the surface of T cells without transfected CD5 blocking virus was 99.5% (shown as B in FIG. 6), suggesting that 12C-ER could bind to CD5 in cells and retain it in the endoplasmic reticulum. Thus, this CD5 expression blocking technique can be used to block CD5 expression on cells, preventing suicide phenomena that target CD5CAR-T cells.

Example 5 in vitro killing of CD 5-positive tumor cells by CD5CAR-T cells with blocked CD5 expression

Cytotoxicity of CD 5-positive acute lymphoblastic leukemia cells (CCRF-CEM) by CD5CAR-T cells blocked by 5.1CD5 expression

In vitro killing experiments of acute lymphoblastic leukemia cells (CCRF-CEM) by CD 5-expressing blocked CD5CAR-T cells were performed by incubating with CCRF-CEM cells at 4:1, 2:1, 1:1 target-to-target ratios for 16 hours, respectively, and LDH release experiments assessed the killing function of 12C.b CAR-T cells. The results are shown in figure 7, where CD5CAR-T cells had significant specific killing of CCRF-CEM cells compared to control under conditions of different effective target ratios.

Cytokine secretion after incubation of 5.2CD5 expression blocked CD5CAR-T with CCRF-CEM cells

The killed supernatant was collected and assayed for IFN-gamma secretion following killing of the CCRF-CEM cells by 12C.b CAR-T cells by ELISA. The results are shown in FIG. 8, where T cells were substantially free of secretion of the cytokine IFN-gamma following co-incubation with CCRF-CEM cells, and where 12 C.b. CAR-T significantly increased IFN-gamma secretion levels following killing of CCRF-CEM cells.

Example 6 in vivo anti-tumor effects of CD5CAR-T cells with blocked CD5 expression

To assess the in vivo antitumor activity of CD5CAR-T cells with blocked CD5 expression, a mouse xenograft model was constructed using the T-ALL cell line Jurkat cells (cellcok, cat# CC 1902). Jurkat-luc cell line at 3X 10 ⁶ Tail vein injection of individual cellsAfter injecting NSG mice for 11 days, all animals were imaged, tumor-bearing uniform mice entered the experimental group, and were randomly divided into 3 groups (4 mice per group) respectively as a frozen stock solution group (Control), a Mock T cell group, and a CD5CAR-T cell group. Wherein, the freezing solution is injected into the tail vein of the freezing solution group (Control), and the tail vein of the Mock T cell group is injected 1 multiplied by 10 ⁷ Tail vein injection of individual cells, CD5CAR-T cell group 1X 10 ⁷ Individual cells (CD 5 CART with blocked CD5 expression prepared in example 3)

Following dosing treatment Day3, day7, day12, day17, day24 and Day33 anesthetized mice, injected intraperitoneally with Luciferase substrate, and tumor burden was observed using an in vivo imaging system for small animals, the results are shown in fig. 9. The result shows that almost no tumor cells are imaged in the CD5CAR-T cell treatment group, and the mouse tumor burden of the frozen stock group and the Mock T cell group is serious, which shows that the CD5CAR-T cells can effectively remove CD5 positive tumor cells, and has remarkable in vivo anti-tumor effect.

Claims

1. A chimeric antigen receptor that targets a CD5 molecule, wherein said chimeric antigen receptor comprises a 12C single domain antibody; the 12C single domain antibody comprises a heavy chain variable region CDR1, a CDR2 and a CDR3; the amino acid sequences of the CDR1, the CDR2 and the CDR3 are shown as SEQ ID NO.15-SEQ ID NO. 17.

2. The chimeric antigen receptor according to claim 1, wherein the amino acid sequence of the 12C single domain antibody is SEQ ID No.1 or a sequence having 85% homology with SEQ ID No.1.

3. The chimeric antigen receptor according to claim 1, wherein the chimeric antigen receptor further comprises a signal peptide, an extracellular region, a transmembrane region, and/or a cytoplasmic region.

4. The chimeric antigen receptor according to claim 3, wherein the chimeric antigen receptor further comprises a self-cleaving region and/or a retention domain.

5. The chimeric antigen receptor according to any one of claims 1-4, wherein the chimeric antigen receptor is obtained by sequential tandem connection of: signal peptide of CD8 molecule, 12C single domain antibody, CD8 finger+tm region, 4-1BB cytoplasmic region, cytoplasmic region of CD3 zeta molecule, T2A self-cleaving region, 12C single domain antibody, ER retention domain.

6. The chimeric antigen receptor according to claim 5, wherein the amino acid sequence of the signal peptide of the CD8 molecule is shown in SEQ ID No. 2; the amino acid sequence of the CD8 finger+TM region is shown as SEQ ID NO. 3; the amino acid sequence of the 4-1BB cytoplasmic domain is shown as SEQ ID NO. 4; the amino acid sequence of the cytoplasmic region of the CD3 zeta molecule is shown as SEQ ID NO. 5; the amino acid sequence of the T2A self-shearing region is shown as SEQ ID NO. 6; the amino acid sequence of the ER retention domain is shown in SEQ ID NO. 7.

7. The chimeric antigen receptor according to claim 6, wherein the amino acid sequence of the chimeric antigen receptor is shown in SEQ ID No.9.

8. A nucleic acid encoding the chimeric antigen receptor of any one of claims 1-7.

9. The nucleic acid of claim 8, wherein the nucleic acid has a sequence as shown in SEQ ID No.8 or a sequence having 80% or more sequence homology with SEQ ID No. 8.

10. A modified T cell comprising, expressing and/or secreting the chimeric antigen receptor according to any one of claims 1 to 7.

11. The T cell of claim 10, wherein said T cell is a CAR-T cell.

12. A cell culture comprising the T cell of any one of claims 10-11, wherein the cell culture comprises a chimeric antigen receptor that targets a CD5 molecule.

13. A medicament comprising the chimeric antigen receptor of any one of claims 1-7 or the T cell of any one of claims 10-11 or the cell culture of claim 12.

14. The medicament of claim 13, further comprising pharmaceutically acceptable excipients.

15. Use of the chimeric antigen receptor of any one of claims 1-7 or the T cell of any one of claims 10-11 or the cell culture of claim 12 in the preparation of an anti-tumor medicament.

16. The use of claim 15, wherein the neoplasm comprises a T cell malignancy.

17. Use of the chimeric antigen receptor of any one of claims 1 to 7 or the T cell of any one of claims 10 to 11 or the cell culture of claim 12 for the preparation of a medicament for the prevention and/or treatment of an immune disorder.

18. The use according to claim 17, wherein the immune disorder comprises rheumatoid arthritis, systemic lupus erythematosus, type I diabetes and/or myasthenia gravis.

19. A CD5 detection kit comprising the chimeric antigen receptor of any one of claims 1-7 or the T cell of any one of claims 10-11 or the cell culture of claim 12.

20. A method of CD5 detection comprising the chimeric antigen receptor of any one of claims 1-7 or the T cell of any one of claims 10-11 or the cell culture of claim 12 or the kit of claim 19, said method being a non-disease diagnostic or therapeutic method.