Epitopes of Mycobacterium avium ssp. paratuberculosis 70 kDa heat-shock protein activate bovine helper T cells in outbred cattle.

The recombinant 70 kDa heat-shock protein of Mycobacterium avium subspecies paratuberculosis (MAP Hsp70) has been shown to be an immunodominant antigen and a subunit vaccine candidate for bovine paratuberculosis. The aim of the present study was to define MAP Hsp70 specific T cell epitopes in cows immunized with MAP Hsp70 and cows experimentally infected with MAP. Nine peptides were shown to induce proliferation and interferon-γ production by lymphocytes from MAP Hsp70 immunized cattle. From 28 calves experimentally infected with MAP 82% responded to at least one of the 5 most immunodominant peptides, indicating relevance of the epitopes during infection. In these 28 animals 15 different BoLA class II haplotypes were present indicating that the peptides were presented by multiple BoLA class II DRB3 alleles. These findings indicate the potential of the MAP Hsp70 subunit vaccine as a tool to control paratuberculosis in outbred cattle populations.