Preparation method of artificial antibody

Abstract

The invention relates to a preparation method of an artificial antibody, which is characterized by comprising the following steps: screening a target siRNA from a coronavirus conserved gene or a microsatellite, synthesizing a small hairpin shRNA with a loop ring from two complementary positive and negative siRNA chains, synthesizing ACE2 taking a receptor binding domain RBD as a ligand, respectively connecting the ACE2 to the positive and negative chains of the shRNA, synthesizing the artificial antibody formed by a shRNA region and an ACE2 region, and carrying out screening to obtain the artificial antibody. Wherein the bivalent ACE2 has the effects of neutralizing RBD and targeted delivery of shRNA, the shRNA is connected with a virus through the ACE2 and enters a target cell along with the infection of the virus, so that the side effect of non-specific delivery of the shRNA to an uninfected cell can be avoided, and the effects of anti-variant strains and neutralizing the virus by the ACE2 can be generated; in addition, an artificial antibody synthesized by two molecules of ACE2 and one molecule of shRNA and an immunologic adjuvant effect of shRNA enable ACE2 to have stronger antigenicity, and anti-ACE2 generated by stimulating an organism also has an antiviral effect.

Description

technical field [0001] The invention relates to a preparation method of a broad-spectrum antiviral artificial antibody, which belongs to the field of biopharmaceuticals for the prevention and treatment of infectious diseases. Background technique [0002] The main structure of the new coronavirus includes single-stranded positive-stranded nucleic acid (ssRNA), spike protein (S), membrane protein (M), envelope protein (E) and nucleocapsid protein (N), of which the N-terminus of the S protein is composed of It consists of a structural domain (S1-NTD) and a receptor binding domain (S1-RBD), and the novel coronavirus causes infection by binding to the host cell receptor ACE2 through its receptor binding domain S1-RBD. [0003] ACE2 is a type I transmembrane glycoprotein composed of 805 amino acids, including the transmembrane region, the intracellular carboxyl terminus and the extracellular amino terminus. The coronavirus interacts with the extracellular catalytic domain of ACE2...

AI Technical Summary

Problems solved by technology

Small interfering RNA (siRNA) is about 21-23bp, regulates gene expression by participating in RNA interference (RNAi), and specifically degrades the complementary target messenger RNA (mRNA). Gene interference has to overcome many difficulties: 1) Membrane permeability: siRNA has a large amount of negative charges and a large molecular weight (~13KD), and it is difficult to pass through the cell membrane itself. The transport of siRNA mainly depends on chemical modification and some transport carriers; 2) Anti-nuclease degradation: siRNA is composed of a large number of ribonucleic acid molecules, which are easily degraded by external RNases. If no specific chemical modification of bases or carrier protection methods are used when designing siRNA and selecting transport carriers, the siRNA will enter 3) Targeted delivery and carrier: the action site of siRNA is mainly in the target cell plasma, so it is necessary to specifically deliver siRNA to the target cell plasma, if the appropriate target cannot be effectively selected Delivery vectors and timely release of siRNA from endosomes to the cytoplasm usually activate cellular immune responses and lead to the release of interferon and other cytokines. Therefore, how to effectively transport and release siRNA to the target cell plasma affects the effect of RNAi Bottleneck problem, some siRNAs can lead to sequence or concentration-dependent non-specific gene silencing, that is, off-target. Therefore, when designing siRNAs, targeted delivery, gene suppression effects, and sequences with low off-target effects should be selected at the same time

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