Vaccines bacterial fermentation

The bacteria and bacterial components needed for the manufacture of bacterial vaccines are readily prepared in laboratory media by well-recognized fermentation methods. The end-product of the fermentation, the harvest, is processed to provide a concentrated and purified vaccine component that may be conveniently stored for long periods or even traded as an article of commerce. 

Biological sources are primarily used for vaccines. Vaccines are suspensions of living or killed micro-organisms, components or products thereof. They are produced in living systems. Eggs are the most widely used medium at present, notably for influenza vaccines, but there is increasing use of animal cell cultures. Bacterial vaccines, for example, the diphtheria vaccine, can be cultured. There is an overlap here with fermentation processes (Section II.D.). 

The other major health care products produced with the help of industrial fermentation are bacterial vaccines, therapeutic proteins, steroids, and gene therapy vectors. There are two categories of bacterial vaccines living and inactivated vaccines. Living vaccines consist of weakened, also known as attenuated, bacteria. Examples of living vaccines include those for diseases such as anthrax, which is caused by Bacillus anthracis, and typhoid fever, which is caused by Salmonella typhi. Inactivated vaccines are composed... 

The basic process technology in vaccine production consists of fermentation for the production of antigen, purification of antigen, and formulation of the final vaccine. In bacterial fermentation, technology is weU estabHshed. For viral vaccines, ceU culture is the standard procedure. Different variations of ceU line and process system are in use. For most of the Hve viral vaccine and other subunit vaccines, production is by direct infection of a ceU substrate with the vims. 

Biopharmaceuticals that are industrially produced by microbial (bacterial or yeast) fermentation include insulin, human growth hormone, hepatitis B surface antigen vaccine, alpha interferon, beta interferon, gamma interferon, granulocyte colony stimulating factor, and interleukin-2. Table 30.8 lists some of the major biopharma products, some of which are produced by mammalian cell culture. 

Detoxification. The process by which bacterial toxins are converted to harmless toxoids. Formaldehyde is used to detoxify the toxins of Corynebacterium diphtheriae, Clostridium botu-linum and Cl. tetani. The detoxification may be performed either on the whole culture in the fermenter or on the purified toxin after fractionation. Traditionally the former approach has been adopted, as it is much safer for the operator. However, the latter gives a purer product. The pertussis toxin used in acellular vaccines may be detoxified with formaldehyde, glutaraldehyde, or both, hydrogen peroxide or tetranitromethane. In the case of genetically detoxified pertussis toxin, a treatment with a low concentration of formaldehyde is still performed to stabilize the protein. 

Medical and diagnostic products, such as monoclonal antibodies, insulin, interferon, various cell-line stimulating factors, anti-clotting agents, enzyme inhibitors, steroids, antibiotics as well as bacterial and viral vaccines, are manufactured by means of aseptic fermentation from different raw materials by microbial and animal cell cultures. 

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