Vaccines designed to protect against Mycobacterium tuberculosis infection may aid the identification of novel vaccine constructs and diagnostic antigens for bovine tuberculosis

Vaccination has been identified as a promising control strategy for tuberculosis in both humans and cattle. Recent heterologous prime-boost approaches combining BCG vaccination with subunit boosts have shown considerable promise in both fields. However, the identification of further protective antigens is still a research priority. In this paper we have established the response hierarchy in Mycobacterium bovis infected or BCG vaccinated cattle of 6 Mycobacterium tuberculosis-derived proteins that were protective against M. tuberculosis in the guinea pig aerosol challenge model. Two of these proteins, Rv1806 and Rv3812, were recognised most frequently in cattle and therefore constitute potential subunit vaccine candidates that merit further evaluation in cattle. Their epitopes were mapped in infected cattle and were shown to be located primarily in the non-conserved regions of these PE/PE-PGRS protein family members. The aim of this study was to ascertain the presence of any correlation between the immunogenicity of defined antigens in different animal species. A weak association between guinea pig immunogenicity (as measured by protection) and antigenicity in M. bovis infected or BCG vaccinated cattle was found.