Mycoplasma hyopneumoniae is the etiological agent of swine enzootic pneumonia, one of the most important respiratory diseases in pigs. The aim of this project is to determine if a a recombinant chimeric antigen of M. hyopneumoniae fused to the B subunit of heat labile enterotoxin of E. coli, is able to induce protection against an experimental M; hyopneumoniae infection in pigs.