Sistemas carreadores de proteínas antigênicas da membrana de Pasteurella multocida para a prevenção da pasteurelose

Abstract

Pasteurellosis is a common disease in the respiratory tract of commercial and/or biomedical rearing of research rabbits. The bacterium Pasteurella multocida is the pathogen responsible for a range of clinical syntomes, including chronic rhinitis (snuffles), otitis media, pneumonia, genital infection, pulmonary and cutaneous abscesses, conjunctivitis and hemorrhagic septicemia. However, between 50 and 70 % of the animals can harbour the microorganism asymptomatically. The factors that cause the clinical syntomes include the ammonium accumulation in the air (foul ventilation), pregnancy, another concomitant disease, disorder in the rabbit production environment and experimental manipulation. Outbreaks of this disease occur in Brazil with relative frequency; however diagnosis is generally based on the clinical signals and necropsy. Therefore, it is difficult to estimate the extent of losses caused by pasteurellosis druing cuniculture. However, specific commercial vaccines against pasteurellosis in rabbits are not available and prevention is through the use of antibiotics in drinking water, even though this type of treatment generally does not protect the animals. Initially, pure bacteria colonies were obtained, which were cultivated in specific growing media (BHI). The microorganisms were isolated, lysed and the antigenic proteins were detected by SDS-PAGE and Western Blotting. These results show that most protein bands were recognized by the policlonal antibody against P. multocida. Since this protein pool presented antigenicity, the protein mixture was solubilized by incubating 0,5 mg/ml of the membrane fraction with SDS 1 % (w/v) under constant agitation for 2 hours. This procedure resulted in a 85 % solubilization yield. The proteoliposomes wew formed using a lipid, protein and detergent cosolubilization method. A good yield of protein incorporation in liposomes seems to be related to the methodology used for the removal of the detergent from the lipid:protein:detergent mixture during the co-solubilization process, as well as the nature of the phospholipid used. The results indicated that the Calbiosorb resin was the most efficient for SDS removal and, among the various phospholipids tested, DPPC best