Rough Lipopolysaccharide from Brucella abortus and Escherichia coli Differentially Activates the Same Mitogen-Activated Protein Kinase Signaling Pathways for Tumor Necrosis Factor Alpha in RAW 264.7 Macrophage-Like Cells

The intracellular, gram-negative pathogen Brucella abortus establishes chronic infections in host macrophages while downregulating cytokines such as tumor necrosis factor alpha (TNF-α). When producing TNF-α, Brucella abortus rough lipopolysaccharide (LPS) activates the same mitogen-activated protein kinase signaling pathways (ERK and JNK) as Escherichia coli LPS, but Brucella LPS is a much less potent agonist.