diphtheria pertussis vaccine is the abbreviation of pertussis , diphtheria, and tetanus combined vaccine, covering three infectious diseases with high morbidity and mortality in the early 20th century.
In 1883, German doctor Edwin Klebs discovered the pathogenic microorganism in the stained smears of the albuginea taken from the throats of patients with diphtheria. The following year, Prussian military doctor Friedrich Loeffler cultured and isolated Corynebacterium diphtheriae, and proved that the symptoms of diphtheria were caused by an exotoxin produced by the bacteria during the infection process.
In 1884, German scientist Arthur Nicolaier associated tetanus with anaerobic bacteria in patients' wounds, and hypothesized that the disease was caused by the spread of toxins. In 1889, Japanese researcher Kitasato Shibasaburo was the first to culture and isolate Clostridium tetani .
and B. pertussis were discovered slightly later than the first two bacteria. In 1901, Jules Bordet and Octave Gengou, working at the Institut Pasteur, first observed this bacterium in the tissues of whooping cough patients. In 1906, the causative agent of whooping cough was successfully “captured”.
When the causes of the disease surfaced, research and treatment of these three diseases began.
Discovery and Application of Antitoxin
At the Koch Institute for Infectious Diseases in Berlin, Emil von Behring and his colleague Kitasato Shibasaburo discovered that sublethal doses of tetanus toxin can be Or diphtheria toxin can be injected into experimental animals to obtain a serum that can prevent and cure the disease in other animals. Bellin called this serum an antitoxin and speculated that it was the product of active immunization of animals with the bacterial toxin . When injected into another animal, this toxin could protect it from disease through passive immunization of with . Invasion. That is, the "passive transfer" of antibodies from the blood of infected animals can make new animals immune to tetanus or diphtheria. Gradually, their experimental subjects evolved from guinea pigs to rabbits, sheep, goats and horses. From 1892 to 1893, sheep-derived antitoxin entered clinical trials and significantly reduced the mortality rate.
Behring won the first Nobel Prize in Physiology or Medicine in 1901. He was a brilliant man, famous for discovering the diphtheria and tetanus vaccines . During the First World War, his tetanus vaccine saved the lives of millions of wounded soldiers.
With the growing demand for anti-toxins, commercial large-scale production is imminent, but two problems must be solved before formal production. First, in order to control virulence, the production of antitoxins requires the use of uniform bacterial strains. Second, the antitoxin is obtained by extracting the serum of immunized animals. Due to differences in different animals, the effectiveness of serum is also uneven. How to standardize the serum? Fortunately, scientists used bacteriology and immunology technologies to overcome these two problems respectively. Among them, the original standardized serum developed by bacteriologist Ehrlich became the first international standard reference preparation and played an important role in the development of future serum and vaccines.
Diphtheria antitoxin not only has therapeutic value, but also has certain preventive value. Tetanus antitoxin has limited therapeutic value after the onset of symptoms. In the early 20th century, research found that tetanus antitoxin was valuable in wound management and could be injected locally to prevent the spread of toxin from tetanus bacterial spores that had entered the skin.
In the last decade of the 19th century, Behring and Kitasato Shibasaburo developed serum therapy for the treatment of diphtheria and tetanus. This was certainly a milestone in history, but the research of bacteriologist Ehrlich was crucial to the production of high-quality Diphtheria antitoxin is also critical. In the first few years, due to the difficulty in controlling the dose of antitoxin, serum therapy was unable to achieve a breakthrough. It was not until 1897 that Ehrlich developed a method for measuring the content of diphtheria antitoxin and proposed the concept of "minimum lethal dose", and the standardization of antitoxin was finally achieved. Land.It can be said that Ehrlich was the greatest contributor to the large-scale production and clinical use of diphtheria antitoxin.
Kitasato Shibasaburo
"poison" and "antidote" are given together
As a passive immunity method, the antitoxin cannot form sustained protection for the human body, and the immune system of some patients will react to horse antibodies - this is a The life-threatening side effect is also called " serum sickness ". To this end, scientists hope to develop active immune agents with long-lasting protective effects, known as vaccines.
Diphtheria toxin, although deadly, can induce the body to produce long-lasting antibodies. Scientists imagine: If a protective antitoxin is injected at the same time as the toxin, can a higher potency antitoxin be produced without making people sick? From 1897, a combination of diphtheria toxin and antitoxin was used for commercial antitoxin production in horses, with the mixture proving to be more effective than the antitoxin alone. In 1909, Theobald Smith established a practical method for balancing such mixtures to maximize their effectiveness. In 1914, a diphtheria toxin-antitoxin mixture began to be used for disease prevention.
Horses are the main source of serum in the era of mass production of antitoxins.
The discovery and improvement of toxoids
Toxoids, as the name suggests, are a weakened form of toxins secreted by bacteria. Although the toxicity is weakened, the immunogenicity of remains unchanged. That is, toxoids are capable of eliciting a protective immune response but do not cause any disease caused by the active toxin. Therefore, toxoids are an excellent choice to replace certain bacterial toxins.
Ehrlich first noticed this inactivated form of bacterial toxin in the late 1890s. In 1904, Ernst Lowenstein and Alexander Granny successfully immunized horses with toxins inactivated by formaldehyde and (formalin). In 1907, Theobald Smith demonstrated that toxoid immunized guinea pigs and found that the protection was long-lasting and might help prevent disease in humans.
Nearly 20 years later, Alexander Granny and Barbara Hopkins accidentally converted diphtheria toxin into toxoid through the action of formaldehyde. However, the resulting toxoid product still requires an antitoxin to ensure its safety initially. In the same year, Gaston Ramon developed a practical method to produce diphtheria toxoid by formaldehyde and heat inactivation and used it to induce active immunity in humans in the absence of antitoxin. Since the antigenicity of diphtheria toxoid is relatively weak and it is difficult to stimulate the body to produce high levels of antibodies, Ramon suddenly came up with the idea of adding various ingredients to the vaccine, such as sterilized tapioca , calcium, magnesium and aluminum salts. , lanolin , kaolin and other preparations are only designed to enhance immunogenicity and prolong immunity time. As mentioned above, the experiment, which he described as "interesting," was successful.
In 1926, Granny precipitated diphtheria toxoid using potassium aluminum sulfate or alum , so that it could persist in tissues for a long time and provide long-lasting protection. The precipitate included aluminum hydroxide and aluminum phosphate mixture. Since then, aluminum salts have entered the stage of history as the most commonly used vaccine adjuvant. Later, scientists made many improvements to the chemical substance, eventually forming today's diphtheria toxoid vaccine.
The development of tetanus toxoid is similar to the development of diphtheria toxoid. The emergence of tetanus toxin-antitoxin mixture was initially mainly used to immunize animals. In 1926, Ramon and Christian Zoeller immunized humans with tetanus toxoid. A few years later, the use of aluminum salt adjuvants greatly improved the immune effect.
Pertussis vaccine: the popular "third party"
Different from the relatively single variety of diphtheria and tetanus vaccines, early pertussis vaccines came in various forms, most of which were whole-cell vaccines, such as various inactivated and partially detoxified by heat or chemical substances. Bacterial preparations, as well as mixed preparations including other bacteria from the upper respiratory tract flora.
In 1914, the first pertussis vaccine was licensed by the Massachusetts Public Health Biology Laboratory; a mixture of diphtheria toxin and antitoxin became available that same year. In 1926, alum-precipitated diphtheria toxoid was licensed and in 1937, tetanus toxoid was licensed. It can be seen that the pertussis vaccine was recognized earlier than the other two vaccines, so why should it be integrated into the diphtheria and tetanus vaccines to make the famous diphtheria-tetanus vaccine (DTP, the English abbreviation of diphtheria-tetanus vaccine, Diphtheria, tetanus and whooping cough)?
First of all, diphtheria and whooping cough are common childhood infectious diseases, and the vaccination targets are similar. Second, scientists found that whole-cell pertussis vaccines are effective adjuvants. The combination of the three antigens in DTP improves the immunogenicity of the toxoid compared with individual administration. Thirdly, the aluminum-adsorbed vaccine also further improved the immunogenicity of the pertussis vaccine and reduced the severity of its related adverse reactions. In other words, the whole-cell pertussis vaccine can serve as an adjuvant for diphtheria and tetanus toxoid vaccines, and the aluminum salt used to precipitate the toxoid can improve the immunogenicity of the pertussis vaccine and reduce serious adverse reactions. The addition of whooping cough vaccine makes one plus two greater than three, truly achieving a "win-win situation" for all three parties. Faced with such a "third party", what reason does mankind have not to welcome it?
Whole cell pertussis vaccine with adjuvant attribute
Why does whole cell pertussis vaccine have its own adjuvant attribute? As mentioned above, the "Four Diamonds" of adjuvants - aluminum salt, emulsion , TLR agonist and saponin - are essential "spice" for making vaccines. Since the whole-cell diphtheria-tetanus vaccine (DTWP, where WP specifically refers to the whole-cell pertussis vaccine, that is, whole-cell pertussis vaccine) contains aluminum salts for adsorbing precipitated toxoids, what does the whole-cell pertussis vaccine contain?
whole-cell pertussis vaccine is produced by inactivating the complete whooping cough bacteria and contains almost all bacterial components. In other words, the whole-cell pertussis vaccine not only contains the pertussis antigen components we need, but also contains components of the bacterial cell wall , such as lipopolysaccharide , and as mentioned above, lipopolysaccharide is an agonist of TLR4. Because it contains two different adjuvant components, aluminum salt and lipopolysaccharide, the DTWP vaccine can be said to be the predecessor of modern new adjuvant vaccines.
Acellular pertussis vaccine makes its debut
On the one hand, because of the joining of the whole-cell pertussis vaccine, DTP unexpectedly gained adjuvant properties; on the other hand, the whole-cell pertussis vaccine has a variety of ingredients and insufficient purity, which inadvertently causes Security risks. Although scientists have conducted rigorous evaluations and have not found a causal relationship between the vaccine and serious adverse reactions, sudden infant death syndrome , and chronic encephalopathy, the impact of some "vaccine-related events" has led to restrictions on whooping cough vaccines in some areas. Acceptance plummeted, and whooping cough, which had once nearly disappeared, made a comeback. The only gratifying thing is that this series of events has further promoted the development of the subunit vaccine strategy.
In the early 1980s, acellular pertussis vaccine (aP) was introduced. Unlike wP, aP only contains specific bacterial components, such as formaldehyde-treated toxins that are effective in controlling whooping cough; it does not contain lipopolysaccharide, which is considered the culprit of whole-cell reactogenicity. Currently, developed countries or regions usually use the main or only pertussis vaccine in combination with tetanus toxoid and diphtheria toxoid, which is the common DTaP. When the acellular pertussis vaccine that removes components such as lipopolysaccharide comes onto the scene, as the adverse reactions caused by the vaccine are reduced, the effect of the adjuvant will be correspondingly weakened, but there is currently no evidence that its efficacy has significantly decreased.
At this point, the famous "iron triangle" toxoid vaccine-100 diphtheria tetanus vaccine was formed. Today, the DTP combination vaccine has become one of the most widely used vaccines in the population.
DPT vaccine is a model of modern new adjuvant vaccine. The World Health Organization requires that all children around the world receive routine immunization with DPT vaccine and maintain immunity during adolescence and adulthood.Maintaining this level of population immunity will require continued vaccination of newborns, as well as booster vaccinations for adolescents and adults. In recent years, epidemiological data show that the incidence of pertussis in my country has been on a significant upward trend, which shows that it is urgent to promote widespread active immunization with DPT vaccine.
