Importance of the Omp25/Omp31 family in the internalization and intracellular replication of virulent B. ovis in murine macrophages and HeLa cells

The role of the outer membrane proteins of the Omp25/Omp31 family in invasiveness and intracellular survival of virulent B. ovis in phagocytes was analyzed. The absence of Omp25d or Omp22 in B. ovis abolished its invasive capacity in HeLa cells and reduced it in J774.A1 cells. Additionally, in J774.A1 cells, the Δomp25d mutant was unable to multiply, whereas the Δomp22 mutant was cleared at 24 h post-infection. These findings demonstrate that Omp25d and Omp22 are essential for the invasion and survival of B. ovis inside host cells, and justify the strong attenuation in virulence of the Δomp25d and Δomp22 mutants.