Polypeptide specifically bound with tuberculosis-positive serum and diagnosing kit

Abstract

The invention provides polypeptide capable of being specifically bound with tuberculosis-positive serum. The polypeptide is one or a combination of A and B, wherein the amino acid sequence of the A is shown as SEQ ID NO: 1; the amino acid sequence of the B is shown as SEQ ID NO: 2. The invention further provides a serological tuberculosis diagnosing kit. The kit contains the polypeptide specifically bound with the tuberculosis-positive serum. The invention further provides a tuberculosis diagnosing kit based on phage display polypeptide. The kit contains a core phage P1 and a core phage P4, wherein the core phage P1 is phage of display polypeptide A; the core phage P4 is phage of display polypeptide B. The polypeptide and the corresponding core phages provided by the invention are high in sensitivity and specificity, and have a good clinical diagnostic value.

Description

technical field [0001] The invention provides a polypeptide capable of specifically binding to tuberculosis-positive serum, a diagnostic kit based on the polypeptide, and further relates to a diagnostic kit for tuberculosis based on a phage-displayed polypeptide, which belongs to the field of biological preparations. Background technique [0002] Mycobacterium tuberculosis (Mycobacterium tuberculosis, Mtb) was discovered in 1882 by German bacteriologist Robert Koch (Robert Koch) and confirmed as the pathogenic bacteria causing tuberculosis (Tuberculosis, TB). The bacteria can invade various tissues and organs of the whole body, but the most common infection is the lungs. According to WHO statistics, about one out of every three people in the world is infected with Mtb. In some developing countries, the carrier rate of Mtb in adults is as high as 80%, and about 5% to 10% of the carriers can develop into active tuberculosis. [0003] At present, the diagnosis methods for tube...

AI Technical Summary

Problems solved by technology

[0003] At present, the diagnosis methods for tuberculosis mainly include the following: (1) Bacteriological diagnosis: including sputum smear microscopic examination and sputum sample culture method, among which sputum smear microscopic examination is simple, fast and reliable, but its sensitivity is poor; The sample culture method is the gold standard for tuberculosis diagnosis, but it takes a long time and has a high false negative rate; (2) serological diagnosis: the serological diagnosis of tuberculosis mainly uses immunological techniques to detect specific anti-Mtb antibodies in serum

(3) Tuberculin skin test: it is a skin test for diagnosing type IV hypersensitivity reaction caused by Mtb infection. Mycobacteria and Bacillus Calmette-Guerin (BCG) cross-react

(4) Mtb nucleic acid amplification detection: This method has good sensitivity, and even bacteria with low copy number in the specimen can be detected, but there will be deviations in clinical application, such as improper specimen handling, cross-contamination of target sequences or amplification products, etc. prone to false negatives

(5) IFN-γ release test: It is a new method for in vitro immunoassay of tuberculosis. Generally, enzyme-linked immunosorbent assay (ELISA) or enzyme-linked immunospot test (ELISPOT) is used to measure the production of IFN-γ in whole blood or peripheral blood mononuclear cells. The number of T cells and cytokine changes of IFN-γ, but this method is costly and requires high technical requirements

However, in the traditional method of using protein antigens for serological diagnosis, it is necessary to clone and express related genes first, and then use affinity chromatography to purify the protein, which is time-consuming and laborious, and the process of protein expression and purification is susceptible to many aspects factors

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