Author: Zhixing
On October 20, 2017, scientists from the State University of New York at Buffalo stated in an article published in the Journal of Science Advances that developed a new pneumonia vaccine with a three-fold effect as traditional vaccines.
Blaine Dr. Pfeifer's team found that this vaccine can produce an immune response to 72 Streptococcus pneumonia strains, and the existing vaccines are only targeting the 23 most threatening Streptococcus pneumonia strains. It is obvious that this new vaccine broadens the immunity range and is effective for strains that have not previously produced an immune response, which may greatly reduce the mortality rate of children caused by pneumonia.
According to statistics from the World Health Organization, the number of children killed by pneumonia in 2004 was 2 million, and by 2015 this number was below 1 million, but the police still cannot be relaxed. Streptococcus pneumoniae, which causes pneumonia, is a bacteria that normally exists in the upper respiratory tract of the human body and generally does not cause diseases. However, when the body's immunity decreases, especially after respiratory virus infection or infants and young children and elderly and weak people with low immunity are prone to lung infection of Streptococcus pneumonia , and many reports of HIV patients who have been infected with pneumonia and die.
The pathogenicity of Streptococcus pneumoniae is closely related to its capsule . The capsule is not only its source of virulence, but also divides Streptococcus pneumoniae into different types. When penicillin was initially discovered, Streptococcus pneumoniae were also highly sensitive to it, but the heavy use of penicillin Streptococcus pneumoniae began to show resistance.
vaccines with different antibiotic mechanisms solve this problem. Different strains of Streptococcus pneumoniae express a unique capsular polysaccharide on the surface, and the vaccine works according to this medium. Existing vaccines such as Prevnar 13 and Synflorix can bind polysaccharides on the surface of a specific strain to the CRM197 protein, thereby activating the immune system to eliminate Streptococcus pneumoniae. Since the polysaccharides expressed by different Streptococcus pneumoniae are specific, specific vaccines can only have an effect on specific strains, which limits the scope of the vaccine's effect, and also leads to high research and development costs and long cycles of vaccines.
Streptococcus pneumoniae acts as a bacteria that lives normally in the human body. It will only cause harm to the human body when it develops to a certain extent. Although the vaccine mentioned above is effective, it cannot distinguish between the normal bacterial flora of and the harmful bacterial flora. When killing the pathogenic Streptococcus pneumoniae, it will cause harm to other microorganisms, thereby destroying the balance of microbial flora.
Traditional vaccines kill bacteria in the body (Streptococcal pneumonia that does not cause pneumonia). But now we know that bacteria in the body - a large part of microorganisms are beneficial to maintaining the health of the body. 'Other scholar of the study, Charles H. Jones, said, 'It is exciting now that the vaccine we developed has the ability to monitor bacteria and only attack the bacteria that cause the disease.' This is of great significance, and the harmless bacteria that are retained will also prevent the growth of harmful bacteria. '
The above mentioned are two shortcomings of the existing Streptococcus pneumoniae vaccine. One is that the scope of action is narrow and it is not difficult to deal with strains that may cause mutations at any time; the other is that it has a certain degree of blindness. The continuous understanding of the internal environment tells us the importance of maintaining the balance of microbial organisms in the body. We cannot kill friendly forces by mistake in order to eliminate the enemy.
According to the research results of the article, it can be seen that this new vaccine combines the strengths of the two vaccines (Prevnar and Pneumovax), which not only causes a strong immune response, but also combines with a variety of polysaccharide markers, increasing the range of immune response. The key to this vaccine is an liposome . On the one hand, it serves as the storage location of polysaccharides, which can closely bind to the capsular polysaccharides of various Streptococcus pneumoniae; on the other hand, corresponding proteins are added to the liposome surface, which causes an immune response when combined with the capsular polysaccharides of the pathogenic Streptococcus pneumoniae and kills the pathogenic bacteria.
In the experiments conducted on mice and rabbits, this vaccine had an immune response to all 72 strains in more than 90 known strains of Streptococcus pneumoniae. And, in most cases, its effect exceeds that of Prevnar and Pneumovax.The mechanism of action of
vaccine can be simply shown in the figure below. Green indicates other pathogenic bacteria, blue indicates normal streptococcal pneumoniae, and red indicates pathogenic streptococcal pneumoniae. The leftmost indicates that the vaccine also has an effect on other pathogenic bacteria; the middle indicates that Streptococcus pneumonia is still within a controllable range and is not pathogenic; the rightmost indicates that the vaccine combines with Streptococcus pneumonia that causes the disease, and the immune system kills it.
We have made significant progress in our confrontation with preventing the spread of pneumonia, especially in childhood patients. 'Pfeifer said, 'But if we want to get rid of the disease completely, we also need to develop smarter and more effective vaccines. 'Although the vaccine is still in the animal testing stage, it is a good start.
Reference source:
1. Pneumonia vaccine triples protection in animal models;
2. The end of pneumonia? New vaccine offers hope.
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