Antigens of Actinobacillus pleuropneumoniae and their use in the design of vaccines, especially glycoconjugates

Actinobacillus pleuropneumoniae (further: A. pleuropneumoniae) is microaerophilic, Gram-negative bacteria belonging to the Pasteurellaceae family. This pathogenic microorganism is a major cause of porcine pleuropneumonia and fibrinous pleurisy, highly contagious diseases of the respiratory tract, affecting predominantly young pigs. Pleuropneumonia and fibrinous pleurisy can be diagnosed due to cough combined with a high mortality and the common infection route is direct transfer of bacteria by aerosol. A. pleuropneumoniae is a significant factor for economic losses in the swine industry all over the world. Progress made in research concerning a new potential vaccine enables the development of technology for designing safe, new candidates which could provide full protection against most of A. pleuropneumoniae serotypes. Several immunogenic factors of A. pleuropneumoniae have been found, including carbohydrate antigens, protein molecules and lipostructures. Carbohydrate antigens, as capsular polysaccharides (CPS) and lipopolysaccharides (LPS), have a special place due to their properties and wide potential. Some of these microbial structures were used to create subunit vaccines containing polysaccharide-protein conjugates, which seem to be a promising solution. The prevention methods, such as vaccines, should minimize medical expenses and financial losses. This article shows a wide repertoire of A. pleuropneumoniae antigens and focuses on one of the most promising strategies in vaccine design – glycoconjugate vaccines.