Method for purifying pneumococcal capsular polysaccharide

Abstract

The invention relates to a method for purifying pneumococcal capsular polysaccharide and belongs to the field of biological products. The method for purifying pneumococcal capsular polysaccharide comprises the following steps: cracking bacteria of a streptococcus pneumoniae inactivated and fermented liquid, carrying out clarification and ultra-filtration to obtain ultra-filtration concentration liquid, precipitating by using low alcohols and carrying out ultra-filtration, degrading protein and nucleic acid into micromolecule fragments through enzymic catalytic reaction under the specific reaction condition by using protease and nuclease, further finely purifying after purifications processes of ultra-filtration and chromatography in subsequent processes to obtain purified pneumococcal capsular polysaccharide. The method is mild in reaction condition, simple and convenient to operate; the process is liable to control; the defects of the prior art can be overcome; poisonous and harmful chemical reagents such as phenols, chloroform and acetone are not used; the method is environmentally friendly and friendly to operator; the prepared capsular polysaccharide is high in recovery rate while the content of protein and nucleic acid is reduced.

Description

technical field [0001] The invention belongs to the field of biotechnology, in particular to the field of vaccines; the invention relates to a method for purifying capsular polysaccharide, in particular to a method for extracting and purifying capsular polysaccharide of Streptococcus pneumoniae without using phenol. Background technique [0002] Streptococcus pneumoniae is the main pathogenic bacterium that causes pneumonia-like diseases and upper respiratory tract infections such as otitis media, sinusitis, and bronchitis. In severe cases, it can cause central nervous system, heart valves, and bone and joint infections through the blood circulation system. At present, the injection of polyvalent pneumonia capsular polysaccharide vaccine is an effective means to reduce the infection of Streptococcus pneumoniae in children over 2 years old and high-infected people. [0003] In the fermentation process of Streptococcus pneumoniae, in addition to synthesizing capsular polysacch...

AI Technical Summary

Problems solved by technology

[0004] Due to the different chemical properties of the capsular polysaccharides of different serotypes of Streptococcus pneumoniae, the nature and content of impurities such as proteins and nucleic acids synthesized in the fermentation process are also different. Therefore, each serotype of capsular polysaccharides needs to use organic solvents (lower alcohols, Chloroform, acetone, phenol, etc.) step-by-step precipitation, enzyme digestion, ultrafiltration and other methods to remove protein and nucleic acid contamination, but so far there is no general method that can purify the capsular polysaccharides of 23 serotypes of Streptococcus pneumoniae, in production , all adopt the process of purifying capsular polysaccharides for different serotypes respectively

[0005] For the existing purification process of Streptococcus pneumoniae capsular polysaccharide, among currently listed pneumonia products (such as 23-valent pneumococcal polysaccharide vaccine), in the purification process of pneumococcal capsular polysaccharide, a large amount of phenol, chloroform, acetone, etc. are often used. Organic solvents that are harmful to humans and the environment. The disadvantage of this method is that during the extraction process of organic solvents, severe shaking will cause polysaccharides to degrade, break or lose their initial spatial conformation, and the purified polysaccharides will lose their immunogenicity.

At the same time, these organic reagents need to be used multiple times in the purification process, which not only increases the operation steps and time, but also increases the risk of cross-contamination

Images