[Improvement of veterinary vaccines through the use of new adjuvants]

A large number of infectious diseases in man and animals may be prevented by vaccination today, but (satisfactory) vaccines are not yet currently available for all forms of infection. Various reasons may be given to account for this fact, such as slight effectiveness of the experimental vaccines so far developed, limitations of large-scale production, storage and distribution of vaccines, etcetera. Recent developments in the fields of molecular biology, virology, bacteriology and immunology offer new opportunities for the development and improvement of vaccines. Two types of vaccine are distinguished, viz. dead and live vaccines. Live vaccines usually produce a stronger and longer-lasting immunity than dead vaccines, and the latter require the assistance of compounds which promote immunity, so-called adjuvants. However, the adjuvants used today tend to give rise to untoward side-effects, or are only moderately effective. The use of new and safer substances as substitutions for adjuvants which are currently administered may help to produce improved vaccines. A number of aspects of adjuvants, such as their possibilities and limitations, the variety of compounds having an adjuvant effect and possible mechanisms of action will be discussed in the present paper.