RESUMO
The currently available anti-pneumococcal vaccines are based on capsular polysaccharide (PS), plain or conjugated to a carrier protein. Conjugated vaccines are expensive products, especially in the case of pneumococcus, in which reasonable coverage requires from 7 to 13 serotypes. To obtain increased coverage with fewer components, we evaluated the immunogenicity of the pneumococcal surface protein A (PspA), conjugated to capsular polysaccharide serotype 23F, aiming at induction of an immune response against both components. Mice immunized with PS23F-rPspA1 conjugate produced antibodies against both PS and rPspA1, comparable or slightly higher than that obtained by free PS. The immunized animals challenged with a lethal dose of a virulent strain bearing a homologous PspA, showed that the PS23F-rPspA1 conjugate induced higher survival than rPspA1 alone or in combination with PS. This increased protection was shown to correlate with the enhanced capacity of the antibodies to bind to the pneumococcal surface and to induce complement deposition. Our results indicate that the use of PS-PspA conjugates may be a way to increase coverage against pneumococci with fewer components.
Assuntos
Humanos , Streptococcus pneumoniae/classificação , Streptococcus pneumoniae/imunologia , Vacinas Conjugadas/classificação , Vacinas PneumocócicasRESUMO
Factor VIII was purified from porcine plasma using adsorption on aluminium hydroxide with CM-cellulose as a filtration aid, cold ethanol precipitation, and two anion-exchange (Q-Sepharose fast flow) chromatographies. The final product was purified 264-fold and had a specific activity of 10 U mg-1. The method is suitable to produce purified porcine FVIII by an easy process where all steps can be scaled up. The final product is free of von Willebrand factor that is responsible for the main side effects in patients. Finally, this method can be used to obtain purified porcine plasma FVIII for use in haemophilic patients with inhibitors.
