Vaccine production

Development of new-generation vaccines

Based on fundamental knowledge of genes, scientists have developed technologies for creating recombinant DNA. This has brought the production of biological products to a fundamentally new level of safety. Today, there are three main groups of innovative agents for vaccine prophylaxis:

• Genetically engineered vaccines. A classic example is the hepatitis B vaccine. It is completely safe because it does not contain the whole pathogen: the isolated viral antigen is artificially synthesized in ordinary yeast cells.
• Synthetic vaccines. Constructed by combining purified antigenic determinants with polymeric carriers or special adjuvants that enhance the immune response.
• Live vector vaccines. Use safe microorganisms as a kind of "transport" to deliver the required genetic material.

Biotechnology and microbial synthesis

Using genetic engineering techniques, specialists can transfer genes both between related bacteria and between microorganisms of completely different species and genera. Microbes obtained in this way are called genetically modified organisms (GMOs) or transgenic, and the approach itself is called GMO technology.

The achievements of genetic engineering are widely applied in biotechnology. The production of medical products using microbiological synthesis is economically much more profitable than obtaining them by chemical means. The main reason lies in incredible productivity: just a single microbial cell is capable of synthesizing about 100,000 protein molecules per minute. Organic synthesis does not possess such speeds.

In addition to vaccines, yeast cells or Escherichia coli cells are used to massively produce:

• Genetically engineered insulin.
• Interferons and interleukins (1, 2, 3, 6).
• Tumor necrosis factor, thymus peptides, and myelopeptides.
• Antibiotics, vitamins, and amino acids.
• Food proteins and antitumor drugs.

Immunogenetics and modern diagnostics

Genetic engineering has opened new horizons not only in the prevention but also in the treatment of diseases. The introduction of drugs based on monoclonal antibodies has revolutionized targeted therapy and the creation of precise diagnostics.

Within immunogenetics, the following areas are actively developing:

1. The use of genetic diagnostics, primarily PCR (polymerase chain reaction).
2. Development of gene prophylaxis methods.
3. Gene therapy for various immunodeficiency states.
4. The use of immunomodulators in infectious and non-infectious pathologies.

Louis Pasteur: the birth of biotechnology

French scientist Louis Pasteur (1822–1895), a chemist by training, thanks to his experimental talent became the father of several sciences at once: microbiology, biotechnology, desinfectology, and stereochemistry.

His path began with chemistry. At age 26, he defended his thesis on arsenic compounds (potassium, sodium, ammonia). Studying crystals, he made a crucial conclusion: when growing fungi, only specific stereoisomers are assimilated. This discovery made him the founder of stereochemistry.

Later, Pasteur revolutionized the understanding of the nature of fermentation. Before him, Liebig's chemical theory dominated science. Pasteur irrefutably proved that lactic acid, alcoholic, and acetic acid fermentation is a purely biological process caused by microorganisms and their enzymes. This discovery marked the birth of biotechnology.

Refutation of dogmas and combatting microbes

In the 19th century, there was an old dogma about spontaneous generation: it was believed that living things could arise spontaneously from non-living matter (e.g., frogs from silt or microbes from dirt). Pasteur conducted an elegant experiment with a flask featuring a spirally curved tube («swan neck»). The nutrient broth communicated with the air, but dust and microbes settled in the glass bends. Life did not originate in the sterile broth. But as soon as the tube was removed, providing direct contact with air, the broth quickly sprouted microorganisms.

Among Pasteur's other major achievements:

• Discovery of anaerobiosis. He was the first to discover the existence of microorganisms capable of living and reproducing without access to oxygen.
• Pasteurization. Saving wine from "diseases" (rotting and unwanted fermentation), he developed a method of heating liquids to 50–60 °C. This destroyed vegetative forms of bacteria and laid the foundation for the principles of asepsis and disinfection.
• Immunology. Pasteur developed the fundamental principle of vaccination and methods for producing vaccines, forever changing the approach to combating infections.

Class and exam questions

What else to study on this topic

• Mechanisms of creating recombinant plasmid DNAs
• Application of monoclonal antibodies in diagnostics and therapy
• Genetic diagnostics and principles of polymerase chain reaction (PCR)
• Gene therapy of immunodeficiency states and the use of immunomodulators
• Discovery of anaerobiosis: the life of microorganisms without oxygen

Other topics in the section "Introduction to microbiology and immunology"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.