Vaccine production bacterial

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. 

Moist heat (<100°C) Cold/freezing Ionizing radiation Disinfection Preservation Sterilization Inactivation of bacterial cells (56°C) in vaccine production See text... 

Starting in the 1920s, very many different mixed bacterial vaccine products (including inactivated bacteria such as Staphylococcus aureus. Streptococcus species. Streptococcus pneumoniae, Moraxella catarrhalis, Klebsiella pneumoniae, H. influenzae) were marketed worldwide. Currently, there are still several products available in European countries, and one product in the USA. Most vaccines have been used for treatment of recurrent and chronic infections of the respiratory tract. The efficacy of these products is doubtful. Delayed hypersensitivity to bacterial products is common. Delayed reactions, sometimes associated with vague malaise or myalgia, can occur after the administration of maintenance doses for months. If delayed skin reactions are accompanied by any systemic symptoms, administration of the mixed vaccine should be drastically reduced or stopped (87). 

The starting point for the production of all microbial vaccines is the isolation of the appropriate infectious agent. Such isolates have usually been derived from human infections and in some cases have yielded strains suitable for vaccine production very readily in other instances a great deal of manipulation and selection in the laboratory have been needed before a suitable strain has been obtained. For example, bacterial strains may need to be selected for high toxin yield or production of abundant capsular polysaccharide viral strains may need to be selected for stable attenuation. 

Vaccines against bacterial disease are commonly directed against the toxins produced by the bacteria. The toxins are purified and treated to prevent them from causing their debilitating effects on the host (toxoids). The toxoids retain their immunogenicity and thus their ability to cause antibody production, which provides immunity to the bacterial pathogen. A well known example is the diphtheria toxoid. 

Vaccine production is pursued with the objectives to genetically engineer vaccines with specific gene deletions reducing virulence produce viral and bacterial vectored vaccines and develop subunit vaccines using purified antigens obtained from in vitro expression vectors such as pseudorabies purified protein vaccine and foot-and-mouth disease vaccine. 

SIMON B E and leong j c (2003) A review of recombinant vaccines for aquaculture Bacterial systems for vaccine production and delivery, in Bhojwani S S and Soh W-Y (eds), Agrobiotechnology and Plant Tissue Culture. Enfield, NH Science Publishers, 169-189. 

Veterinary biologies are placed into two Classes, based on the properties of the preparation. Class I products include inactivated r-DNA-derived viral vaccines inactivated r-DNA derived bacterial vaccines viral, bacterial, cytokines or other subunits, monoclonal antibody products and vaccines containing live organisms modified by gene insertion or deletion, without introduction of foreign DNA. 

Despite these potential advantages, the preferred source of antigenic polysaccharides for vaccine production remains isolation from bacterial culture. Isolation and chemical modification is usually a simpler process than chemical total synthesis. 

The nature of the conditions of intensive production, however, can increase the risk of diseases and infections which can spread very rapidly and devastate large numbers of animals." Thus it is common practice for producers of poultry to add coccidiostats to their diets and vaccines to their drinking water in order to prevent coccidiosis and other infectious diseases such as bronchitis and Newcastle disease. A similar problem exists for intensively reared fish, where it is necessary to add antibiotics to their diets. A problem with intensively reared fish is that their diet is added directly into the water in which they live thus drugs and other additives in the diet are relatively easily dispersed into the local environment of fish farms, where they can increase bacterial resistance and also cause problems such as algal blooms. 

Production of the bacteria and the bacterial components of bacterial vaccines... 

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. 

The harvest is a very eomplex mixture of bacterial cells, metabolic products and exhausted medium. In the ease of a live attenuated vaccine it is innocuous and all that is necessary is for the baeteria to be separated and resuspended in an appropriate menstmum, possibly for freeze-drying. In a vaccine made Irom a pathogen the harvest may be intensely dangerous and great care is necessary in the following procedures. 

The single-component bacterial vaccines are listed in Table 15.1. For each vaccine, notes are provided of the basic material fkm which the vaccine is made, the salient production processes and tests for potency and for safety. The multicomponent vaccines that are made by blending together two or more of the single component vaccines are required to meet the potency and safety requirements for each of the single components that they contain. The best known of the combined bacterial vaccines is the adsorbed diphtheria, tetanus and pertussis vaccine (DTPerWac/Ads) that is used to immunize infants, and the adsorbed diphtheria and tetanus vaccine (DTWac/Ads) that is used to reinforce the immunity of school entrants. 

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