RESUMO
Expression vectors containing rabies virus nucleoprotein B-cell and T-cell epitopes in Mycobacterium bovis BCG were constructed. The epitopes were subcloned into the M. leprae 18-kDa gene to ensure correct presentation to the host immune system. Expression of the 18-kDa::B+T epitope fusion protein was driven by either the hsp60 promoter, which is constitutively activated at a high level in M. bovis BCG, or the 18-kDa promoter, which is strongly induced in vivo. Mice were immunised intra-peritoneally with the recombinant BCG cultures and compared to a control group vaccinated with the commercial rabies vaccine Rai-SAD. Both of the expression vectors elicited a higher antibody titre than that of the rabies vaccine, with the highest response shown by M. bovis BCG (pUP203), expression controlled by the 18-kDa promoter. Immunisation with M. bovis BCG (pUP202), expression controlled by the hsp60 promoter, resulted in a continuously increasing antibody titre up to 60 days post immunisation. The mice antibodies were also capable of recognising the whole rabies virus and not only the synthetic peptide epitopes.
Assuntos
Antígenos Virais/genética , Mycobacterium bovis/genética , Mycobacterium bovis/imunologia , Nucleocapsídeo/genética , Nucleocapsídeo/imunologia , Vírus da Raiva/genética , Vírus da Raiva/imunologia , Animais , Anticorpos Antivirais/biossíntese , Linfócitos B/imunologia , Sequência de Bases , Epitopos/genética , Expressão Gênica , Vetores Genéticos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Proteínas do Nucleocapsídeo , Plasmídeos/genética , Vacina Antirrábica/genética , Vacina Antirrábica/imunologia , Linfócitos T/imunologia , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologiaRESUMO
The production and testing of a probiotic formulated with a strain of Bacillus cereus (Probiotic CenBiot) is reported. The strain was grown in fed batch fermenters, desiccated, and mixed with cornflour. To test the effect of the probiotic in controlling piglet diarrhoea, two groups of sows and their respective litters received feed supplemented with probiotic CenBiot or Furazolidone; the control group received the same basic feed but not supplemented. Probiotic CenBiot was as effective as Furazolidone, reducing the prevalence of diarrhoea to half that in the control group. It also significantly improved feed conversion, daily weight gain and total weight gain in pigs in the nursery phase. Feed conversion ratios of weaned pigs were 1.904, 2.146 and 2.099 for the groups that received Probiotic CenBiot, a commercial probiotic, and basic feed, respectively. In terms of food consumption, the Probiotic CenBiot group consumed 12.6% less than the commercial probiotic group, and 10% less than the control group, to achieve the same weight.
