Cholesterol, ganglioside GM1 and class A scavenger receptor contribute to infection by Brucella ovis and Brucella canis in murine macrophages

The establishment of infection by Brucella ovis and Brucella canis in J774.A1 macrophages was found to be dependent upon cholesterol and ganglioside GM1, two components of lipid rafts. This process also required a class A scavenger receptor of macrophages, and was not inhibited by smooth and rough lipopolysaccharides from Brucella spp. In response to infection, both bacteria induced a weak degree of macrophage activation. These results demonstrate that B. ovis and B. canis use cell surface receptors common to smooth Brucella spp. for macrophage infection, thus limiting macrophage activation and favouring intracellular multiplication and/or the survival of both bacteria.