Vaccine development general

Even if private enterprises tend to be more efficient, government entry would be desirable if private vaccine development and production is unlikely to be responsive to enhanced financial incentives (or equivalently, lower disincentives). But evidence from the vaccine, pharmaceutical, and other industries indicates that private investment in R D is generally very responsive to changes in such incentives, including policy-induced changes. 

This chapter first provides a description of immunity in general and then more specifically, immunity in the mucosal immune system. The immune response of both intestinal and respiratory tracts will be described in detail as these are the two most common portals of targeted vaccine development for mucosal immunity. The chapter will cover the basis of mucosal immunity using plant-based oral vaccines. Strategies for increasing mucosal immunity, such as the use of adjuvants, will also be discussed. Finally, the chapter will cover the precliiucal tests and various cliiucal trials that are taking place with respect to production of human and veterinary therapeutic proteins in plants. 

The remarkable success that has been achieved with identification of protective, recombinant antigens against the Taenia and Echinococcus species has been in stark contrast to the general lack of success that has been achieved with vaccine development against other parasitic helminth infections (Dalton and Mulcahy, 2001). Hence, very little direction has been available from the experiences of others on how to translate a laboratory success with an anti-parasite vaccine into a practical (commercial) vaccine. First principles would suggest a host of issues that require investigation/opti-mization, for example ... 

Figure 10.2-1 Maximizing the benefit-to-risk in vaccine development. No vaccine can be administered to humans without solid data showing safety. Product development and safety testing for these products relies very heavily on animal studies which are relied upon to predict both efficacy and safety. Toxicity assessments for vaccines are challenging because, in general, vaccines trigger complex immune reactions.There must be a balance between desired immunogenicity and unwanted adverse side effects.

Not only have encouraging results been obtained with models of vims infection such as the influenza vims system but they have also been reported in several cancer models The destmetion of cancer cells is often dependent on a vigorous CTL response and there is every reason to believe that efficient delivery of tumour-specific CTL epitopes could provide off the shelf cancer vaccines. A realisation of the central role that dendritic cells play in the efficient presentation of antigen to the immune system is nowhere more evident than with the development of anti-cancer vaccines and it is possible that successes in this area could provide a momentum which will benefit peptide vaccines in general. 

Vaccines are used in either the general population of children or adults or for special groups. Recommendations for vaccine usage are made by the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control. The Committee on Infectious Diseases of the American Academy of Pediatrics (Redbook Committee) also makes recommendations for infants through adolescents, and the American Academy of Family Physicians makes recommendations for adults. An excellent review of vaccine history, development, usage, and related regulatory issues is available (2). 

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