Abstract
Vaccines have been well accepted and used effectively for more than 100 years. Traditional vaccines are generally composed of whole inactivated or attenuated microorganisms that have lost their diseaseβcausing properties. These classical prophylactic live vaccines evoke protective immune responses, but have often been associated with an unfavorable safety profile, as observed, for example, for smallpox and polio myelitis vaccines1, 2. First improvements were subunit vaccines that do not focus on attenuation of whole organisms but concentrate on particular proteins. These vaccines are able to generate protective immune responses (e.g. diphtheria, tetanus, pertussis)3. However, next generation vaccines should focus on specific antigens (e.g. proteins, peptides), since the requirements by regulatory authorities to crude biological material are becoming more stringent over time. An increasing number of such antigens capable of inducing protective humoral or cellular immune responses have been identified in the last few years. But most of these are weak immunogens. This reemphasizes the need for adjuvants to promote a potent immune response and also for delivery antigens to the immune system in an appropriate way (carrier capability). Here we review a new approach for prophylactic and therapeutic vaccines, which focuses on the induction of highly specific immune responses directed against antigenβderived peptides using a suitable carrier system. Copyright Β© 2005 European Peptide Society and John Wiley & Sons, Ltd.