Chimeric antigen receptor (CAR) targeting bispecific sites and application thereof

Abstract

The invention belongs to the technical field of gene engineering, and particularly relates to a bispecific single-chain antibody, a CAR structure containing the bispecific single-chain antibody, an expression vector, an immune cell and application. In the single-chain antibody, the amino acid sequence of a Linker1 structure is shown as SEQ ID NO:17 or a functional variant thereof; the amino acid sequence of a Linker2 structure is shown as SEQ ID NO:18 or a functional variant thereof; the Linker1 is connected with a heavy chain variable region of ScFv1 and a light chain variable region of ScFv2 or is connected with a heavy chain variable region of the ScFv2 and a light chain variable region of the ScFv1; and the Linker2 is connected with the light chain variable region of the ScFv2 and the heavy chain variable region of the ScFv2. The construction of the CAR structure overcomes the technical effect defect of a double-target CAR in the prior art; two different tumour antigens can be targeted at the same time; the killing rate of tumour cells is improved; and the immune escape probability of the tumour cells is reduced.

Description

technical field [0001] The invention belongs to the technical field of genetic engineering, and specifically relates to a bispecific single-chain antibody, a CAR structure comprising the bispecific single-chain antibody, an expression vector, immune cells and applications. Background technique [0002] CAR-T (Chimeric Antigen Receptor T) cell therapy has achieved remarkable results in the treatment of hematological malignancies. However, due to the heterogeneity of tumors, especially solid tumors, more than one target antigen is often expressed on the surface of tumor cells, and with the progress of research, researchers have also found that a small number of patients treated with CAR-T cells have down-regulated or mutated tumor cells and The CAR-T target antigen expressed on its surface escapes (Robbie G. Majzner et al. (2018) TumorAntigen Escape from CAR T-cell Therapy), which eventually leads to poor therapeutic effect and recurrence. Therefore, it is very necessary to d...

AI Technical Summary

Problems solved by technology

However, due to the heterogeneity of tumors, especially solid tumors, more than one target antigen is often expressed on the surface of tumor cells, and with the progress of research, researchers have also found that a small number of patients treated with CAR-T cells have down-regulated or mutated tumor cells and The CAR-T target antigen expressed on its surface escapes (Robbie G.Majzner et al. (2018) TumorAntigen Escape from CAR T-cell Therapy), which eventually leads to poor therapeutic effect and recurrence

Therefore, it is necessary to design a CAR structure targeting multiple targets. If two CARs with different targets are simply expressed at the same time, but different CAR structures have different infectivity, a variety of CAR-T cell subsets will be produced, which is not conducive to the clinical application of the product. Application; if only two simple CAR structures with different targets are connected in series in one carrier, the CAR carrier is too large to transduce T cells, and different structures involve different CAR carrier virus preparation capabilities and different CAR transduction capabilities. There are many factors such as different stimuli produced by T cells and different curative effects

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