Produção e avaliação de uma vacina de subunidade recombinante contra a pneumonia enzoótica suína

Abstract

SUMMARY CONCEIÇÃO, FABRICIO ROCHEDO, Universidade Federal de Pelotas, may 2005. Production and Evaluation of Recombinant Subunit Vaccine Against Swine Enzootic Pneumonia. Advisor: Odir Antônio Dellagostin. Co-Advisor: Swine Enzootic Pneumonia (SEP), caused by bacterium Mycoplasma hyopneumoniae, is the most important respiratory disease in swine breeding. The commonly used vaccines to control this disease consist of bacterins, whose production cost is high and the efficiency is limited. The objective of this study was to develop and to evaluate a new alternative for controlling SEP, based on a recombinant subunit vaccine (rLTBR1) containing the R1 region of P97 adhesin of Mycoplasma hyopneumoniae (R1) fused to the B subunit of the heat-labile enterotoxin of Escherichia coli (LTB). rLTBR1 formed functional oligomers that presented high affinity to GM1 ganglioside. Mice inoculated with rLTBR1 (IN or IM) produced high levels of anti-R1 systemic and mucosal (sIgA) antibodies, which recognized the native P97. On the other hand, mice inoculated with the commercial bacterin did not produce anti-R1 antibodies. The administration route influenced the modulation of the immune response by LTB, showing that IM rLTBR1 induced Th2-biased immune responses and IN rLTBR1 induced Th1-biased immune responses. IN rLTBR1 also induced IFN-γ secretion by lymphocytes. The rLTB showed to be a powerful mucosal adjuvant, stimulating the production of anti-R1 IgA in trachea and bronchi from mice inoculated with rLTBR1 by parenteral route (IM). rLTBR1 may constitute a new strategy for preventing infection by Mycoplasma hyopneumoniae and may have potential for developing vaccines against other infectious diseases as well. Now a day, the efficacy of this vaccine is being evaluated in specific pathogen free swine.