Vaccine components

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 first pertussis whole cell vaccine was a mixture of killed organisms that was associated with frequent local and systemic reactions. In the late 1980s, an acellular pertussis vaccine was introduced that contains purified pertussis components that are immunogenic but associated with fewer adverse reactions. Acellular pertussis vaccine is available in combination with tetanus and diphtheria toxoids. Pertussis is not available as a separate vaccine component. In the spring of 2005, the Food and Drug Administration (FDA) approved tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccines for use in adolescents and adults. 

The intended human formulation of the vaccine is administered to the animals in order to ensure exposure to all of the vaccine components, including the protein or carbohydrate antigen, adjuvant, excipients, and impurities. 

A recent development has been the use of genetically modified plants to produce vaccine components. Examples include common foodstuffs such as tomatoes, bananas, potatoes, and com. The prospects for oral vaccines in bananas especially would appear to be promising since this is a staple food in many tropical countries. Vaccine epitopes have also been produced in the milk of goats, sheep, and cows although these may be difficult to purify, process, and formulate. 

In conclusion, excipients to be used in vaccines must be very carefully selected and justified to the regulatory authorities because these are to be used in millions of healthy subjects. Their safety and compatibility with other vaccine components are of prime importance. Because vaccines of the future will be more and more complex, the need for suitable excipients is also likely to grow. It must be ensured that the excipients do not compromise the immunogenicity of the vaccine and accord maximum stability upon long-term storage. 

Vaginal immunization experiments with a cholera vaccine containing killed vibrios and CTB have been conducted in both the follicular (V-FPimm) and luteal (V-LPimm) menstrual cycle phase. With both producing comparable cervical CTB-specific IgA responses, however, only the V-FPimm induced cervical IgA2-restricted Ab to the bacterial lipopolysaccharide (LPS) vaccine component and induced CTB-specific IgA in rectal secretions. 

The literature on bacterial polysaccharides as vaccine components has been reviewed in this series by Jennings.56 Since then, the subject has been reviewed by Ala Aldeen and Cartwright,57 Dick and Beurret,58 Dintzis,59 Egan,60 Goldblatt,61 Jennings,62-65 Lee,66 Fattom,35,67 Paradiso and Lindberg,68 Peeters,69 and Robbins.10,45"47... 

Vaccine-related databases can be split into two groups whole vaccine databases and databases of vaccine components. This section introduces these two groups of databases individually. 

As a manufactured product, a vaccine is composed of several components. A vaccine antigen(s) is a required component for any vaccine. Such a vaccine antigen can be part of a whole organism (e.g., live attenuated vaccine), a protective protein antigen, or an immune epitope. A live attenuated vaccine usually does not require a vaccine adjuvant that functions as an immune stimulant. However, killed whole organism or subunit vaccines usually need vaccine adjuvants. Otherwise, a weak or nonexistent immune response will be induced. Other vaccine components include vaccine vectors and vaccine preservatives. Databases of these vaccine components are briefly introduced here. 

De Groot AS, Sbai H, Aubin CS et al (2002) Immuno-informatics mining genomes for vaccine components. Immunol Cell Biol 80 255-269... 

Treatment with DNA alone, MVA alone, and in combination was well tolerated in mice. Some of the local reactions observed were considered to be related to the injection procedure rather than to the vaccine components. Other hndings were considered to be incidental in nature and not related to the vaccine treatment. Persistence was assessed by PCR, and results showed that positive signals were observed at the injection sites on both days 46 and 78. Equivocal positive results were observed in some mice (including vehicle controls) in a few other tissues, and these were most likely due to contamination and the high sensitivity of the PCR method. Since there was no persistence in any other tissue except for the injection site, no integration assays were carried out. 

People with a serious allergy to any vaccine component. 

Local administration site reactions occur relatively commonly. Systemic reactions, such as moderate fever, occur in 3% to 5% of vaccinees. Very rarely, high fever, febrile seizures, persistent crying spells, and hypotonic hyporesponsive episodes occur following vaccination. Allergy to a vaccine component and encephalopathy without known cause within 7 days of a permssis vaccine are contraindications to future doses of vaccine. Efficacy of the vaccine is estimated to be about 80%. ... 

In addition to the enhanced uptake of antigens by APCs, poly-L-arginine also exerts its adjuvant effects via the formation of a depot at the injection site (Fig. 3.3). This effect, which is based on ionic interaction of the vaccine components, prolongs the availability of antigen in the body. The consequences are most probably... 

Stability and allows stable delivery of vaccine components to lymphoid tissues, thus generating potent CTL and antibody responses as presented below. 

For Lot B the acellular pertussis vaccine components are produced from B. pertussis cultures grown in Stainer-Scholte medium modified by the addition of casamino acids and dimethyl-betacyclodextrin. Fimbriae types 2 and 3 are extracted from the bacterial cells and the pertussis toxin, FHA, and PRN are prepared from the supernatant. These proteins are purified by sequential filtration, salt precipitation, ultrafiltration, and chromatography. Pertussis toxin is inactivated with glutaraldehyde and FHA is treated with formaldehyde. The individual antigens are adsorbed separately onto aluminum phosphate. Diphtheria and tetanus, toxoids are individually adsorbed onto aluminum phosphate. The adsorbed diphtheria, tetanus, and acellular pertussis components are combined in a sterile isotonic sodium chloride solution containing 2-phenoxyethanol as preservative. Each dose contains 10 pg of PT, 5 pg of FHA, 3 pg of PRN, 5pg of FIM, as well as 15Lf of diphtheria toxoid and 5.0 Lf of tetanus toxoid. 

Acellular pertussis antibody response ELISA assays [13] were run in the study of the acellular pertussis vaccine component of the Diphtheria and Tetanus Toxoids and acellular Pertussis Vaccine Adsorbed (DTaP) to assess vaccine potency before and after irradiation of DTaP Vaccine Lots A, B, and C. 

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