Dynamics of production of MIP-1α, MCP-1 and MIP-2 and potential role of neutralization of these chemokines in the regulation of immune responses during experimental autoimmune neuritis in Lewis rats

Abstract

Experimental autoimmune neuritis (EAN) is an inflammatory autoimmune demyelinating disease of the peripheral nervous system (PNS) and represents an animal model of Guillain–Barré syndrome (GBS), which is a major inflammatory demyelinating disease of the PNS in humans. In the present study, the dynamics of the expression of the chemokines macrophage inflammatory protein-1α (MIP-1α), MIP-2 and monocyte chemotactic protein-1 (MCP-1) were determined in the sciatic nerves of EAN rats. Additionally, the effect of neutralizing antibodies against MIP-1α, MIP-2 and MCP-1 on the clinical course of EAN and the chemokine expression was investigated. The maximum of MIP-1α positive cells in the sciatic nerves was seen on day 14 post immunization (p.i.) correlating with the development of severe clinical signs. Administration of an anti-MIP-1α antibody suppressed the clinical signs of EAN and inhibited inflammation and demyelination in the sciatic nerve. Peak numbers of MCP-1 positive cells in the sciatic nerves were detected on day 7 p.i. Administration of an anti-MCP-1 antibody caused a delay of onset of EAN. However, 4 of the 6 EAN rats receiving the anti-MCP-1 antibody showed the same degree of inflammatory cell infiltration and demyelination in the sciatic nerves as sham-treated EAN rats, whereas only 2 EAN rats had less inflammation and demyelination. The numbers of MIP-2 positive cells reached a maximum on day 21 p.i. Anti-MIP-2 antibody failed to suppress the clinical signs of EAN and the inflammation and demyelination in the sciatic nerves. Only administration of the anti-MIP-1α antibody resulted in a significant reduction in the number of chemokine (MIP-1α)-positive cells and ED1-positive macrophages in the sciatic nerves. The present results demonstrate that MIP-1α and MCP-1 may play a role in the immunopathogenesis of EAN, and that MIP-1α induced trafficking of inflammatory cells can be inhibited by immunoneutralization. Further elucidation of the regulation and coordination of MIP-1α and MCP-1 production may lead to new therapeutic approaches to GBS in humans.