Fusion protein and preparation method and application thereof

Abstract

The invention relates to fusion protein and a preparation method and application thereof, and belongs to the technical field of new medicines. The fusion protein disclosed by the invention comprises anchoring protein and PD-L1 protein. The fusion protein disclosed by the invention can exhibit the functions of the anchoring protein and the functions of the PD-L1 protein at the same time. The in vitro and in vivo animal model experiments conform that the fusion protein map-PD-L1 can be efficiently bonded to a cell membrane (including an endothelial cell membrane of internal organ tissues), can restrain T cell activation and promote T cell apoptosis in vitro, can further realize anchoring modification of in vitro internal organs in an in vivo organ transplanting model, can effectively improve local inflammatory reactions of transplanted substances and prolong the survival period of the transplanted substances, and can be applied to preventing and treating a rejection reaction after clinical transplantation surgeries.

Description

technical field [0001] The invention relates to a fusion protein and its preparation method and application, in particular to an anchor fusion protein and its preparation method and application. Background technique [0002] Transplantation is the preferred route of care for patients with end-stage disease. Acute rejection is still an important cause of chronic rejection and graft loss. Although acute rejection has been controlled to some extent with the development of immunosuppressive drugs, nearly 20% of patients still face the risk of acute rejection after surgery. At present, the clinical prevention and treatment of acute rejection mainly relies on the early postoperative intravenous application of large doses of immune-inducing drugs, but this non-specific, systemic induction program over-suppresses the patient's own immune function, thereby increasing the risk of postoperative Chance of concurrent serious infection. Therefore, it is of great significance to seek a n...

AI Technical Summary

Problems solved by technology

[0006] At present, the methods for expressing new proteins on the surface of cell membranes mainly include genetic engineering technology and GPI-anchored protein technology. However, the former is based on gene transduction, and there are still many unsolved problems: First, gene transduction methods need to rely on carriers, such as viruses And plasmids and other vectors, and such vectors do not have targeting selectivity, the host cells and tissue parts after entering the body are uncertain and uncontrollable, and the adverse consequences caused by this cannot be estimated; secondly, the complexity of the microenvironment in the body , which greatly limits the transfection efficiency of the gene, increasing the load of the carrier will undoubtedly increase the toxicity and side effects; thirdly, the expression of the mature protein needs to go through a series of processes such as nucleic acid transcription, translation, and post-translational protein modification, which is time-consuming And complicated; finally, after the exogenous gene enters the host cell through the carrier, it generally needs to be integrated into the host chromosome to function stably, but this integration is unstable and easily degraded, resulting in the failure of gene transduction

It is precisely because of the above problems that the clinical application of gene transduction is still not optimistic.

At the same time, the existing methods for inducing up-regulation of PD-L1 expression, regardless of gene transfection or gene editing technology, are based on the principle of viral vectors and nucleic acid editing technology, and this type of technology not only has low transfection efficiency, but also has no organ target. Once applied in vivo, there is currently no ability to target host cells and tissue sites. This uncertainty cannot be effectively resolved at present. Therefore, the risks brought about by systemic application are also unpredictable.

[0007] In short, in the existing reports, there are model animals through virus transfection and genetic engineering to achieve high expression of PD-L1 in vivo, but there are still many problems in these methods to serve the clinic, such as: primary cells are not easy to transfect , low transfection efficiency, unstable expression, potential tumorigenicity and other disadvantages; therefore, there is no safe and effective method to achieve high expression of PD-L1 in organs or other transplants in vitro

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