Types of bacterial vaccines


Posted March 15, 2019 by Bonnibelle

Since the late 20th century, molecular biology, immunology, microbiology and other related sciences have developed rapidly.

 
Since the late 20th century, molecular biology, immunology, microbiology and other related sciences have developed rapidly. On this basis, there has been a great development of bacterial vaccine, with the emergence of a variety of modern and new bacterial vaccines such as cancer vaccine and DNA vaccine, which brings new hope for the research, development and production of more safe, stable and protective bacterial vaccine. These new modern vaccines are described below. The types of vaccines are classified as follows:

Component vaccine
Classical attenuated live vaccine and inactivated vaccine are the basis of bacterial vaccine research, but the components of such vaccines are complex and may cause immune side reactions, and their safety and effectiveness need to be further improved. With the progress of science and technology, people's understanding of the specific immune components of various pathogenic bacteria is getting deeper and deeper.

At present, there are many kinds of component vaccines. In essence, they can be divided into polysaccharide based component vaccines and protein based component vaccines. The group A polysaccharide vaccine, approved for production in 1974, was the first bacterial component of the vaccine. Streptococcus pneumonia hammer 1977 root, supachai panitchpakdi n) 14 price polysaccharide vaccine production, in 1983 the WHO expert advice with newly developed pneumococcal polysaccharide vaccine instead of 14 23 price polysaccharide vaccine, the vaccine is covered with serotype supachai panitchpakdi n infection has certain protective effect, but because of the small molecular weight supachai panitchpakdi n polysaccharide capsule, belongs to the antigen of T cells in accordance with the patient, the immature immune system of children under the age of 2 protection is weak, so there are some shortcomings. During this period, it was discovered that the combination of polysaccharides and proteins could stimulate t-cell immunity to help newborn animals develop immunity.

This great discovery opened the door to the development of a polyglycoprotein binding vaccine. According to the polyglycoprotein binding technology, the polyglycoprotein binding vaccine (prp-t) for Haemophilus influenzae type b (Hib), which was developed using tetanus toxoid as carrier, had 95% of the preventive effect against invasive diseases of Haemophilus influenzae type b (Hib), and even 100% of the preventive effect against Hib pneumonia. At present, streptococcus pneumoniae capsular polysaccharide-crm197 vaccine and group A and group C streaming capsular polyglycoprotein conjugate vaccine have been widely used in clinical practice. Many bacteria produce a large number of proteins in the process of growth, and some of these proteins play an important role in the process of bacterial adhesion and invasion. The vast majority of protein antigens belong to T cell-dependent (TD) antigens, which contain T cell and B cell epitopes, can stimulate the body to produce body fluids and cellular immunity, and have the function of immune memory. With the progress of proteomics and genomics, a large number of proteins and their coding genes have been screened out, and the protein component vaccine has become a new research direction of bacterial vaccine. In 1982, Valenzuela recombinant hepatitis b virus surface antigen (HBsAg) gene fragments into sacs, and the recombinant yeast successfully expressed HBsAg. The breakthrough could pave the way for a protein vaccine. In September 1986, the recombinant yeast hepatitis b vaccine produced by Merck was approved by the us FDA, which was the first and most successful protein vaccine currently used. In December 1998, the recombinant borrelia borrelia surface protein A(OspA) vaccine developed by glaxosmithkline was approved by FDA. At present, the development of protein vaccines against vibrio cholerae, typhoid bacillus and bacillus dysentery has entered the animal experiment stage, and the protein vaccine against helicobacter pylori has entered the phase III clinical experiment stage. It is believed that many bacterial protein vaccines will be developed in the near future.

DNA vaccine
DNA vaccine is safe, easy to prepare and store, and can clone multiple target genes on the same plasmid vector so as to achieve the effect of a vaccine to prevent a variety of diseases. More importantly, it simulates the process of antigen expression and induced immune response in the body after infection with exogenous pathogenic microorganisms in a natural state. In 1989, Wolff injected DNA plasmids into the skeletal muscle of mice, and accidentally found that exogenous genes could be expressed in skeletal muscle cells, and the activity of the expression products could be up to 2 months. In 1992, Tang et al. injected the human growth hormone (hGH) gene expressed by CMV promoter into the ears of mice by means of gene gun injection, and detected high titer anti-hGh specific antibody in mice after 3-6 weeks, which directly led to the birth of DNA vaccine. At present, there are a variety of bacterial DNA vaccine research is being carried out worldwide.

Superbug vaccine
"Superbugs" are bacteria that are extremely resistant to antibiotics. With the increasingly serious abuse of antibiotics, the emergence of drug-resistant bacteria and the trend of global epidemic, the family of "superbacteria" is becoming larger and larger, which has become a serious pathogen causing clinical infection and may face the situation of no drug treatment. Accelerating vaccine development is an important measure to combat bacterial resistance.

It is urgent to develop new antibiotics or new treatments for the epidemic trend of superbugs. The development cycle of new antibiotics is long and the development speed of bacterial resistance is much faster than that of new drugs. Vaccination has played an important role in controlling the infection and epidemic of severe pathogenic bacteria in the history of human health. Specific vaccines will control the transmission and infection of superbugs at the source. The use of pneumococcal conjugate vaccine (PCV) has proved to be useful in reducing the infection rate and drug resistance of drug-resistant bacteria. Listed in 2000 the first generation of pneumococcal vaccine for seven pneumococcal conjugate vaccine (was), effectively prevent the 7 kinds of serotype of streptococcus pneumoniae infection, but its protection effect is limited to the serotype don't inside the vaccine, with the extension of vaccine use process, the vaccine serotype strains caused by infection increased, and enhance resistance, mainly for the serotype 19 a. In 2010, a new generation of trivalent pneumococcal vaccine (PCV13) was launched, which can prevent 13 types of streptococcus pneumoniae serotypes, including drug-resistant streptococcus pneumoniae serotype 19A, and significantly reduce the infection of drug-resistant streptococcus pneumoniae including serotype 19A. The application of the pneumococcal vaccine is a successful example of the control of drug-resistant bacterial infections. Both antibiotic-resistant and antibiotic-sensitive bacteria, vaccines can reduce their infections and reduce the spread of antibiotic resistance.

The advantages and characteristics of superbug vaccine are as follows: (1) the use of vaccine is not affected by the existing clinical bacterial resistance mechanism; (2) vaccines can greatly reduce bacterial infections and thus reduce the use of antibiotics. The reduction of antibiotic use will reduce the selection pressure of antibiotic resistance, thus delaying the emergence and spread of bacterial resistance, breaking the vicious circle of "antibiotic use - resistance - antibiotic abuse - pan-resistance". (3) the vaccine has a very strong specificity, only targeting at specific pathogens, and will not affect the normal human flora, which overcomes the side effect of the imbalance of flora caused by the use of antibiotics. Therefore, the research and development of superbug vaccine has been paid attention by WHO, European and American governments, pharmaceutical giants such as Pfizer, novartis and glaxo
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Last Updated March 15, 2019