Epitope peptide in human spawn ZP (zona pellucida) protein 4 and application of epitope peptide

Abstract

The invention discloses an epitope peptide in human spawn ZP protein 4 and an application of the epitope peptide, and particularly relates to a short peptide separated from human spawn ZP protein-4 (a human ZP protein 4 227-463 bit). The formula I of the short peptide is shown as follows: X1-X-X2 (the formula I), and the following characteristics are met: a), the X in the formula I is 6-7 amino acid core fragments; b), the number sum of the X1 and the X2 in the formula I is smaller than or equal to 2; c), the sequences of the core fragments are selected from SEQ ID NO.: 1-6; and d), the short peptide is provided with activity combined with an anti-human ZP 4C antibody, wherein the '-' expresses a peptide link or a peptide joint. The epitope peptide can be combined and applied to detection of the existence or content of various antibodies of anti-human ZP 4 protein in a sample, so that women's sterility caused by ZP autoimmunity can be diagnosed at high specificity and high sensitivity; and besides, the epitope peptide can also be used for preparing recombination human ZP multi-epitope-peptide contraceptive vaccine with safe and effective advantages.

Description

technical field [0001] The invention belongs to the technical fields of bioengineering and immunology, and particularly relates to a group of epitope peptides in human egg zona pellucida protein 4 and applications thereof. Background technique [0002] ZP protein (human egg zona pellucida protein), including ZP4 protein, one of the constituent proteins, also plays an important role in the fertilization process of sperm eggs, and is the second sperm receptor. Anti-ZP antibodies in normal women's serum are generally negative, and the existence of anti-ZP antibodies will bind to ZP protein, which will reduce the motility of sperm, affect sperm passing through cervical mucus and ascending, and affect the combination of sperm and ZP protein, thereby preventing Sperm and egg combine and cause infertility. In infertile women with ZP autoimmunity, there are anti-ZP protein antibodies in the serum, but due to the unavailability of ZP protein antigens, the existing general detection ...

AI Technical Summary

Problems solved by technology

In the general use of 18 or 20-mer long epitope peptide antigen enzyme-linked immunoassay (ELISA) to diagnose autoimmune diseases and such as influenza virus infection, there is often a false positive rate of about 30%, which affects the accuracy of clinical diagnosis and wide application of the established diagnostic method

[0004] The reason for the high false positive rate in this case is very simple, that is: since it is clear that the linear epitope is composed of 3-8 amino acid residues, synthetic peptides of 18 or 20 polymers or longer (too short and difficult to be used as antigens for ELISA coating) It is obvious that there may be N unknown epitopes in the detection panel), and due to many reasons such as natural infection of viruses and bacteria (such as influenza virus infection, etc.) and autoimmune diseases, there are usually tens of thousands of antibodies in the human body. Antibodies with low titers, so these two factors are likely to produce non-specific cross-reactions when the above patient serum dilution is unlikely to be high (generally 1:20-1:100), resulting in high false positive rate detection result

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