Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

FP5

RECOMBINANT BCG Sintesi della relazione

Project ID: ICA4-CT-2000-30032
Finanziato nell'ambito di: FP5-INCO 2
Paese: Brazil

immunogenicity and protective efficacy of rBCG-anaplasma antigen strains

Humoral and cellular immune responses of mice inoculated with recombinant Mycobacterium bovis BCG expressing the MSP1a antigen of Anaplasma marginale were evaluated. The msp1a gene was amplified by PCR and cloned into the mycobacterial expression vectors pUS2000 and pMIP12. Immunization of isogenic BALB/c mice with the rBCG/pUS2000-msp1a construct induced significant seroconversion to MSP1a (p<0,001), which was 26 times above pre-immunization levels at day 63 post initial immunization and which remained stable for the duration of the experiment (6 months). In contrast, rBCG/pMIP12-msp1a induced seroconversion at a level of 6 times above pre-immunization values, which peaked at day 63. Western blot analysis showed that sera derived from mice vaccinated with either rBCG construct recognized both native and recombinant forms of A. marginale MSP1a. In contrast to the humoral response data, immunization with rBCG/pMIP12-msp1a was found to induce a markedly stronger cellular response than that recorded for BCG/pUS2000-msp1a. These results clearly demonstrated the immunogenicity of rBCG expressing the MSP1a antigen and suggested that the immune responses were influenced by the level of antigen expression. Recombinant BCG expressing MSP1a constitutes a potential strategy of immunization against bovine anaplasmosis.

Reported by

UNIVERSIDADE FEDERAL DE PELOTAS
Campus Universitario
96010-900 PELOTAS
Brazil
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