Tetravalent ciliary protein immunogen of enterotoxigenic escherichia coli and preparation method thereof

Abstract

Provided are a tetravalent ciliary protein immunogen of enterotoxigenic escherichia coli and a preparation method thereof. Four ciliary antigen genes of the enterotoxigenic escherichia coli are inserted into a polyclonal site region of a pET24a prokaryotic expression vector in series with the prokaryotic expression vector pET24a as a vector, and the tetravalent ciliary protein immunogen of the enterotoxigenic escherichia coli is obtained. The immunogen chooses four common enterotoxigenic escherichia coli K88, K99, 987P and F18 ciliary antigens of piglets. Through superior combination, strongerimmune function of laying hens can be caused, and the titer of total antibody per unit is higher than that of single immune mixture, so the times of antigen production and immune inoculation injection of the laying hens can be reduced, the titer of the antibody is improved and the production cost is reduced, and better and more economical prevention and treatment of piglet colibacillosis are achieved.

Description

technical field [0001] The invention relates to a preparation method of an immunogen in the technical field of molecular biology and veterinary biological products, in particular to an enterotoxin-type Escherichia coli tetravalent ciliary protein immunogen and a preparation method thereof. Background technique [0002] Piglet colibacillosis is an acute infectious disease caused by enterotoxigenic Escherichia coli (Enterotoxigenic E.coli, ETEC) with high contact and fatal diarrhea. Clinically, the main manifestations are enteritis, enterotoxicity and other symptoms. Due to the difference in the age of piglet growth and the serotype of pathogenic bacteria, the diseases caused can be divided into yellow scour of piglets, pullorum of piglets, edema of piglets and diarrhea of ​​weaned piglets. [0003] 1. Pathogenic process of Escherichia coli [0004] The main ciliated serotypes of enterotoxigenic Escherichia coli are F4, F5, F6, and F18. The pathogenic bacteria adhere to the ...

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Problems solved by technology

[0006] 1. Extensive use of antibiotics not only causes residues in livestock and poultry products but also pollutes the environment

[0007] 2. Escherichia coli has developed drug resistance, and the effect of antibiotic control is not ideal. The incidence of porcine colibacillosis is increasing, especially post-weaning diarrhea, which is a key indicator of piglet feed. The over-use of antibiotics in feed is mainly aimed at the large intestine of pigs. bacillary diarrhea

[0008] 3. Long-term use of antibiotics destroys the micro-ecological environment of the intestinal tract, affects digestion and absorption, and causes growth retardation of pigs in the later stage

[0009] In recent years, with the development of animal husbandry, the occurrence of porcine colibacillosis is increasing day by day, showing an upward trend in various places. The incidence and mortality of colibacillary diarrhea in newborn piglets vary in different regions, and the incidence rate is 5.69% to 86.5% %, the mortality rate is 17.0% to 73.0%, which has caused significant economic losses to the pig industry

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