Fully synthetic carbohydrate-based antibacterial vaccines

Although the enormous progresses achieved by modern medicine, numerous diseases have still a profound impact on public health. Infectious diseases caused by a variety of microorganisms (viruses, fungi and parasites) and bacteria are a global major concern, not only in developing countries, due for instance to the emergence of multidrug resistance. The development of preventative therapies, such as the rational design of novel and more efficient vaccines, may offer a solution to this and other drawbacks. Vaccination is considered by the World Health Organization to be the most cost-effective strategy for controlling infectious disease, since it should confer long-term protective immunity in the population.Carbohydrates play a key role in many molecular recognition phenomena and they can affect any kind of interaction with the immune system. Therefore, saccharide-based antigens (for instance, bacterial capsular polysaccharides or tumor associated carbohydrate antigens) have been studied and employed in the formulation of vaccines. During last years, there has been a growing use of synthetic saccharide antigens for the formulation of vaccine candidates. These structures are indeed chemically well defined, devoid of biologic contaminants and, in principle, available in large amount, compared to material extracted from natural sources. In addition, synthetic saccharide antigens can also serve as haptens in protein conjugates, eliciting highly specific antibodies in animal models and humans.