Borrelia burgdorferi basic membrane protein A stimulates murine macrophage to secrete specific chemokines.

In this study, we investigated the mechanisms that lead to the production of proinflammatory mediators by the murine macrophage cell line, RAW264.7, when these cells are exposed in vitro to recombinant Borrelia burgdorferi basic membrane protein A (rBmpA). Using antibody protein microarray technology with high-throughput detection ability for detecting 25 chemokines in culture supernatant the RAW264.7 cell culture supernatants at 12 and 24 h post-stimulation with rBmpA, we identified two chemokines, a monocyte chemoattractant protein-5 (MCP-5/CCL12) and a macrophage inflammatory protein-2 (MIP-2/CXCL2), both of which increased significantly after stimulation. We then chose these two chemokines for further study. Enzyme-linked immunosorbent assay and real-time polymerase chain reaction revealed that with the increase of rBmpA concentration, MCP-5/CCL12 and MIP-2/CXCL2 showed concentration-dependent increases (p <0.01).Our results indicate that the rBmpA could stimulate the secretion of several specific chemokines and induce Lyme arthritis.