Lamontagne et al. (2007) were able to identify the Omp31b and Omp25 in membrane fragment from B. abortus using mass spectrometry. Moreover, they showed that B. abortus altered the membrane-protein expression pattern after macrophage infection. For instance, the concentration of GroEL, SodC and membrane transport increased in OMVs from B. melitensis under oxidative stress, during macrophage infection (Lamontagne et al., 2009). The gene discussed is HSPD1; the disease is infection.