TECHNICAL FIELD

The present invention relates to the field of cellular immunotherapy, especially to a chimeric antigen receptor comprising a third signal receptor and use thereof.

BACKGROUND OF THE INVENTION

The use of immunological therapy for overcoming tumors has always been an important direction in the application of immunology in translational medicine. With the development of various omics (genomics, proteomics, etc.), tumor cells have been widely recognized due to their immunogenicity caused by mutations, which lays a theoretical foundation for tumor immunotherapy. At the same time, with the accumulation of tumor immunology research itself, tumor immunotherapy has recently made a great progress, and a series of new immunotherapy methods have gradually entered into the clinic. The current tumor immunology research has established the central position of T cell killing in tumor immunotherapy, and the chimeric antigen receptor T cell (CAR-T cell) is a tumor-killing cell which has combined the targeted recognition of antibody and the tumor-killing function of T cell, and generated by artificial modification.

The concept of chimeric antigen receptor T cell was first proposed by Gross, Waks and Eshhar in 1989. They expressed TNP-recognizing antibodies on T cells, achieving the antigen-specific, non-MHC-restricted activation of T cell and enhancement of effect, and proposed the concept of applying the CAR-T technology in tumor treatment. According to this principle, tumor-specific antibodies are embedded into T cells, which will give T cells new tumor-killing capabilities. After that, the CAR-T technology was introduced into anti-tumor clinical trials, but early CAR-T cells are not ideal in final clinical results since their intracellular signaling domain contains only the first signal, and the selected tumor type is a solid tumor. In 2008, the Fred Hutchison Cancer Institute and other institutions used CAR-T to treat B cell lymphoma, although the treatment results were not ideal, the key to this clinical trial is to confirm that the CAR-T treatment with CD20-expressing B cells as the target is relatively safe. Subsequently, in 2010, NCI reported a case of successful treatment of B cell lymphoma, using CAR-T targeting CD19, the patient's lymphoma was controlled, normal B cells were also eliminated, and serum Ig was significantly reduced, providing a theoretical and practical support for the effectiveness of CAR-T in the treatment of B cell-derived lymphomas. In 2011, a team led by Dr. Carl June of the University of Pennsylvania in the United States used CAR-T that specifically recognizes CD19 for the treatment of chronic lymphocytic leukemia derived from B cells, showing a “cure” effect. Clinical trials have been launched in relapsed and refractory acute lymphoblastic cell leukemia, and good results have also been achieved. Due to this breakthrough progress and the development of other immune regulation methods, Science magazine ranked tumor immunotherapy as the number one scientific and technological breakthrough in 2013. This success has caused widespread influence in countries around the world, and countries have begun to carry out a large number of CAR-T-based scientific research and clinical trials of tumor treatment.

The structure of CAR consists of an extracellular antigen recognition domain, an extracellular hinge region, a transmembrane domain, and an intracellular signal transduction domain. The extracellular antigen recognition domain consists commonly of a single-chain antibody, which specifically recognizes a tumor cell membrane surface molecule, or can be a ligand or a receptor of certain tumor-specific antigens. The extracellular hinge region is a spatial structure that separates the antigen recognition domain from the transmembrane domain, and its purpose is to provide a suitable spatial position, so that the extracellular antigen recognition domain can maintain the correct structure and transmit the intracellular signals before and after recognizing the antigen. The transmembrane domain is a structural domain for ensuring the positioning of the CAR molecule on the membrane surface. The intracellular signal transduction domain is a key part of mediating the CAR signal transduction, and is usually a combination of one or several first signals (for the recognition of TCR and WIC-I-peptide complex) and second signals (for the recognition of costimulatory receptor and costimulatory ligand). The first-generation CAR contains only the first signal, the second-generation CAR has one first signal and one second signal, and the third-generation CAR has one first signal and two second signal domains. Although CAR-T has achieved a great success in the treatment of leukemia derived from B cell, its relatively high recurrence rate and low effectiveness for solid tumors are great challenges currently. Therefore, there is an urgent clinic need of developing a new generation of high-efficiency CAR-T currently. In addition to the third-generation CAR-T, there are currently other new CAR-T design strategies, that is, introducing new regulatory molecules independent of CAR on the basis of the second-generation CAR-T to further enhance the function of CAR-T.

The application of CAR-T targeting the B cell surface targeting molecules CD19 and CD20 prepared from the patient's own blood cells in the treatment of B cell leukemia has been relatively mature, but there are a large number of recurrences, even if the response rate is high. In addition, the treatment efficiency for solid lymphoma is relatively low, which is related to the immunosuppressive microenvironment in solid tumors.

In solid tumors, there are a variety of immune cells, tumor cells and stromal cells, which together constitute the tumor microenvironment. The tumor microenvironment is usually immunosuppressive, and can inhibit endogenous anti-tumor T cell responses or adoptive T cells (such as CAR-T) at multiple levels, for example, leading to exhaustion of T cells and loss of tumor killing function, and eventually leading to the clearance of T cells. How to enhance the activation ability of CAR-T in solid tumors so that it can fight against the immune suppression in the tumor microenvironment is an important idea and direction for expanding CAR-T to solid tumor treatment.

However, the current CAR-T domains in clinical use still have insufficient tumor killing and expansion abilities, and have poor efficacy in controlling solid tumors/metastasis. Some CAR-T uses novel regulatory molecules such as IL-12, 4-1BBL, etc. These molecules will also produce non-specific activation effects on other non-CAR-T cells in addition to affecting the CAR-T, which may cause potential immune side effects.

SUMMARY OF THE INVENTION

An object of the present invention is to address the defects in the prior art, provide a chimeric antigen receptor including a third signal receptor and use thereof, and provide a CAR-T cell constructed by a recombinant expression vector of the chimeric antigen receptor, and in the CAR-T cell, the activation of T cells is regulated by a first signal (for recognizing of the TCR and MHC-I-peptide complex), a second signal (for recognizing of co-stimulating receptor and co-stimulating ligand) and a third signal (for recognizing of cytokine receptor and cytokine), which synergistically achieve massive expansion of T cells, exert effector functions, and eliminate infection or tumors.

To achieve the aforesaid object, the present invention utilizes the following technical solutions:

a first purpose of the present invention is to provide a chimeric antigen receptor including a third signal receptor, said chimeric antigen receptor has a structure of scFv(X)-(Y)CD3 zeta-MN;

wherein, X comprises a tumor-targeting antibody or a ligand or receptor capable of binding to a tumor; Y is an intracellular domain of a costimulatory receptor, said costimulatory receptor is selected from ICOS, CD28, CD27, HVEM, LIGHT, CD40L, 4-1BB, OX40, DR3, GITR, CD30, TIM1, SLAM, CD2, CD226; M is an intracellular domain of a gamma chain family cytokine receptor, said cytokine receptor is selected from IL2Ra, IL2Rb, IL4Ra, IL7Ra, IL9Ra, IL15Ra, IL21Ra; and N is an intracellular domain of IL2Rg.

For further optimizing the aforesaid chimeric antigen receptor, the technical means utilized by the present invention further includes:

further, said X is selected from anti-CD19 antibody, anti-CD20 antibody, EGFR antibody, HER2 antibody, EGFRVIII antibody, anti-PSMA antibody, anti-BCMA antibody, anti-CD22 antibody, anti-CD30 antibody. Understandably, X can also be other protein capable of specifically binding a tumor.

Further, said X is an anti-CD20 antibody, said Y is an intracellular domain of 4-1BB, said M is one selected from intracellular domain of IL2Rb, intracellular domain of IL4Ra, intracellular domain of IL7Ra, intracellular domain of IL9Ra, and intracellular domain of IL21Ra.

Further, said scFv(X)-(Y)CD3zeta is scFv-antihCD20-20BBZ with a sequence as set forth in SEQ ID No.1; the sequence of said intracellular domain of IL7Ra is as set forth in SEQ ID No.2; the sequence of said intracellular domain of IL2Rb is as set forth in SEQ ID No.3; the sequence of said intracellular domain of IL4Ra is as set forth in SEQ ID No.4; the sequence of said intracellular domain of IL9Ra is as set forth in SEQ ID No.5; the sequence of said intracellular domain of IL21Ra is as set forth in SEQ ID No.6; and the sequence of said intracellular domain of IL2Rg is as set forth in SEQ ID No.7.

Wherein, each aforesaid sequence is specifically as follows:

SEQ ID No. 1:QIVLSQSPAILSASPGEKVTMTCRASSSVSYIHWFQQKPGSSPKPWIYATSNLASGVPVRFSGSGSGTSYSLTISRVEAEDAATYYCQQWTSNPPTFGGGTKLEIKGGGGSGGGGSGGGGSQVQLQQPGAELVKPGASVKMSCKASGYTFTSYNMHWVKQTPGRGLEWIGAIYPGNGDTSYNQKFKGKATLTADKSSSTAYMQLSSLTSEDSAVYYCARSTYYGGDWYFNVWGAGTTVTVSAAAATTTPAPRPPTPAPTIASQPLSLRPEACRPAAGGAVHTRGLDFACDIYIWAPLAGTCGVLLLSLVITLYCKRGRKKLLYIFKQPFMRPVQTTQEEDGCSCRFPEEEEGGCELRVKFSRSADAPAYQQGQNQLYNELNLGRREEYDVLDKRRGRDPEMGGKPRRKNPQEGLYNELQKDKMAEAYSEIGMKGERRRGKGHDGLYQGLSTATKDTYDALHMQALPPR;SEQ ID No. 2:KKRIKPIVWPSLPDHKKTLEHLCKKPRKNLNVSFNPESFLDCQIHRVDDIQARDEVEGFLQDTFPQQLEESEKQRLGGDVQSPNCPSEDVVITPESFGRDSSLTCLAGNVSACDAPILSSSRSLDCRESGKNGPHVYQDLLLSLGTTNSTLPPPFSLQSGILTLNPVAQGQPILTSLGSNQEEAYVTMSSFYQNQ;SEQ ID No. 3:NCRNTGPWLKKVLKCNTPDPSKFFSQLSSEHGGDVQKWLSSPFPSSSFSPGGLAPEISPLEVLERDKVTQLLLQQDKVPEPASLSSNHSLTSCFTNQGYFFFHLPDALEIEACQVYFTYDPYSEEDPDEGVAGAPTGSSPQPLQPLSGEDDAYCTFPSRDDLLLFSPSLLGGPSPPSTAPGGSGAGEERMPPSLQERVPRDWDPQPLGPPTPGVPDLVDFQPPPELVLREAGEEVPDAGPREGVSFPWSRPPGQGEFRALNARLPLNTDAYLSLQELQGQDPTHLV;SEQ ID No. 4:KIKKEWWDQIPNPARSRLVAIIIQDAQGSQWEKRSRGQEPAKCPHWKNCLTKLLPCFLEHNMKRDEDPHKAAKEMPFQGSGKSAWCPVEISKTVLWPESISWRCVELFEAPVECEEEEEVEEEKGSFCASPESSRDDFQEGREGIVARLTESLFLDLLGEENGGFCQQDMGESCLLPPSGSTSAHMPWDEFPSAGPKEAPPWGKEQPLHLEPSPPASPTQSPDNLTCTETPLVIAGNPAYRSFSNSLSQSPCPRELGPDPLLARHLEEVEPEMPCVPQLSEPTTVPQPEPETWEQILRRNVLQHGAAAAPVSAPTSGYQEFVHAVEQGGTQASAVVGLGPPGEAGYKAFSSLLASSAVSPEKCGFGASSGEEGYKPFQDLIPGCPGDPAPVPVPLFTFGLDREPPRSPQSSHLPSSSPEHLGLEPGEKVEDMPKPPLPQEQATDPLVDSLGSGIVYSALTCHLCGHLKQCHGQEDGGQTPVMASPCCGCCCGDRSSPPTTPLRAPDPSPGGVPLEASLCPASLAPSGISEKSKSSSSFHPAPGNAQSSSQTPKIVNFVSVGPTYMRVS;SEQ ID No. 5:KLSPRVKRIFYQNVPSPAMFFQPLYSVHNGNFQTWMGAHGAGVLLSQDCAGTPQGALEPCVQEATALLTCGPARPWKSVALEEEQEGPGTRLPGNLSSEDVLPAGCTEWRVQTLAYLPQEDWAPTSLTRPAPPDSEGSRSSSSSSSSNNNNYCALGCYGGWHLSALPGNTQSSGPIPALACGLSCDHQGLETQQGVAWVLAGHCQRPGLHEDLQGMLLPSVLSKARSWTF;SEQ ID No. 6:SLKTHPLWRLWKKIWAVPSPERFFMPLYKGCSGDFKKWVGAPFTGSSLELGPWSPEVPSTLEVYSCHPPRSPAKRLQLTELQEPAELVESDGVPKPSFWPTAQNSGGSAYSEERDRPYGLVSIDTVTVLDAEGPCTWPCSCEDDGYPALDLDAGLEPSPGLEDPLLDAGTTVLSCGCVSAGSPGLGGPLGSLLDRLKPPLADGEDWAGGLPWGGRSPGGVSESEAGSPLAGLDMDTFDSGFVGSDCSSPVECDFTSPGDEGPPRSYLRQWVVIPPPLSSPGPQAS;SEQ ID No. 7:ERTMPRIPTLKNLEDLVTEYHGNFSAWSGVSKGLAESLQPDYSERLCLVSEIPPKGGALGEGPGASPCNQHSPYWAPPCYTLKPET

Further, said extracellular hinge region of the chimeric antigen receptor is a region selected from CD8a or IgG; and said transmembrane domain of the chimeric antigen receptor is one selected from CD8a, CD28, CD137 or CD3.

A second object of the present invention is to provide a recombinant expression vector of any one of the aforesaid chimeric antigen receptor.

A third object of the present invention is to provide a CAR-T cell constructed with a recombinant expression vector of any one of the aforesaid chimeric antigen receptor.

A fourth object of the present invention is to provide a method of preparing the aforesaid CAR-T cell including the following steps:

step 1: construction of lentiviral vector and production of virus;

forming a fusion protein of scFv(X)-(Y)CD3zeta, M and N, and adding a lentiviral vector to both ends of the fusion protein, which is co-transfected with lentiviral packaging plasmid to obtain an scFv(X)-(Y)CD3zeta-MN virus;

step 2: preparation of scFv(X)-(Y)CD3zeta-MN CAR-T cell;

isolating a human PBMC for purification, culturing, infecting with the scFv(X)-(Y)CD3zeta-MN virus obtained in Step 1, and subjecting to cell expansion under suitable conditions to prepare scFv(X)-(Y)CD3zeta-MN CAR-T cells.

wherein X is a tumor-targeting antibody or other protein; Y is the intracellular domain of costimulatory receptor selected from ICOS, CD28, CD27, HVEM, LIGHT, CD40L, 4-1BB, OX40, DR3, GITR, CD30, TIM1, SLAM, CD2, CD226; M is the intracellular domain of gamma chain family cytokine receptor selected from IL2Ra, IL2Rb, IL4Ra, IL7Ra, IL9Ra, IL15Ra, IL21Ra; and N is the intracellular domain of IL2Rg.

For further optimizing the method of preparing the aforesaid CAR-T cell, the technical means used in the present invention further includes:

further, the construction of lentiviral vector and production of virus include: forming a fusion protein of scFv(X)-(Y)CD3zeta, M and N by overlap PCR, and adding restriction sites to both ends of the fusion protein to clone a lentiviral vector; subjecting the clones sequenced correctly to a large scale endotoxin-free extraction, and co-transfecting with a lentiviral packaging plasmid; after a predetermined period of time, collecting the supernatant, filtering, centrifuging to concentrate the virus, to obtain the scFv(X)-(Y)CD3zeta-MN virus.

Still further, said construction of lentiviral vector and production of virus are as follows: forming a fusion protein of scFv(X)-(Y)CD3zeta, M and N by overlap PCR, adding EcoRI and BamHI restriction sites to both ends of the fusion protein to clone the pCDH-MSCVEF vector; subjecting the clones sequenced correctly to a large scale endotoxin-free extraction, and co-transfecting with lentiviral packaging plasmid into 293X; after 48 and 72 hours, collecting the supernatant, filtering it with a 0.45 uM filter and centrifuging at 25000 RPM for 2 hours to concentrate the viruses to obtain the scFv(X)-(Y)CD3zeta-MN virus.

Further, the specific steps of preparing the scFv(X)-(Y)CD3zeta-MN CAR-T cell include: isolating human PBMC for purification, inoculating into a culture plate under suitable stimulation conditions, culturing for a predetermined time period, infecting with the scFv(X)-(Y)CD3zeta-MN virus obtained in Step 1, and subjecting to cell expansion under suitable stimulation conditions. After 2 rounds of expansion under stimulation, the obtained cells are the scFv(X)-(Y)CD3zeta-MN CAR-T cells.

Further, the stimulation conditions for culturing the isolated and purified human PBMC are anti-hCD3 and anti-hCD28; and the stimulation conditions for cell expansion are stimulation by use of artificial antigen presenting cell or anti-hCD3/28 every 6 days.

Still further, said specific steps of preparing the scFv(X)-(Y)CD3zeta-MN CAR-T cell are as follows: purifying human PBMC with a Stemcell T cell isolation kit, inoculating into a 96-well culture plate coated by anti-hCD3 and anti-hCD28. After 2 days, infecting the scFv(X)-(Y)CD3zeta-MN virus obtained in Step 1 at MOI=10-20. After 1 day, continuing to culture cells with the medium changed, and stimulating with artificial antigen presenting cell or anti-hCD3/28 every 6 days. After 2 rounds of stimulation, the obtained cells are scFv(X)-(Y)CD3zeta-MN CAR-T.

Further, said X is selected from anti-CD19 antibody, anti-CD20 antibody, EGFR antibody, HER2 antibody, EGFRVIII antibody.

Further, said X is anti-CD20 antibody, said Y is 4-1BB, and said M is one selected from IL2Rb, IL4Ra, IL7Ra, IL9Ra, IL21Ra.

Further, said scFv(X)-(Y)CD3zeta is scFv-antihCD20-20BBZ with a sequence as set forth in SEQ ID No.1; said intracellular domain of IL7Ra has a sequence as set forth in SEQ ID No. 2; said intracellular domain of IL2Rb has a sequence as set forth in SEQ ID No. 3; said intracellular domain of IL4Ra has a sequence as set forth in SEQ ID No. 4; said intracellular domain of IL9Ra has a sequence as set forth in SEQ ID No. 5; said intracellular domain of IL21Ra has a sequence as set forth in SEQ ID No. 6; and said intracellular domain of IL2Rg has a sequence as set forth in SEQ ID No. 7.

Further, said lentiviral packaging plasmid in Step 1 includes VSV-g, pMD Gag/Pol, RSV-REV, and the centrifuging is performed with Beckman ultracentrifuge and SW28 head.

A fifth object of the present invention is to provide a formulation including the aforesaid CAR-T cell or the CAR-T cell prepared by the aforesaid preparation method. Further, said formulation further includes a pharmaceutically diluents or excipient.

A sixth object of the present invention is to provide use of the aforesaid chimeric antigen receptor, the aforesaid CAR-T cell or the CAR-T cell prepared by the aforesaid preparation method in the preparation of a medicament for treating or preventing tumors.

Further, said tumors are solid tumors. Examples of the solid tumors include, but are not limited to, lymphoma, renal tumor, neuroblastoma, germ cell tumor, osteosarcoma, chondrosarcoma, soft tissue sarcoma, liver tumor, thymoma, pulmonary blastoma, pancreatoblastoma, hemangioma, etc.

As compared with the prior art, the present invention has the following beneficial effects:

said CAR-T cell of the present invention significantly increases the tumor killing ability and the expansion ability, and has significantly increased ability of killing solid/metastatic tumors. Said CAR-T cell of present invention includes a third signal receptor (IL2Ra, IL2Rb, IL4Ra, IL7Ra, IL9Ra, IL15Ra, IL21Ra, etc.), which is not a conventionally used ligand or excreted factor. For example, the third signal receptor IL7Ra is primarily expressed in memory CD4 and CD8 T cells, and plays an important role in the long-term survival of T cells and the formation of memory T cells. Integrating the third signal receptor signal into the CAR-T has a potential effect-enhancing function, and only works on the CAR-T cell, thereby reducing the risk of causing an immune side effect.

The present invention constructs a novel CAR-T cell including the third signal receptor, which increases the activation ability and survival ability of CAR-T cells in tumors as compared with the current CAR-T technology in clinic use. The activation ability and expansion ability of the cells are significantly enhanced, so that the CAR-T cell exhibits increased therapeutic effects and has more superior anti-tumor therapeutic effect.

