Divergent Roles of Tumor Necrosis Factor and Platelet-Activating Factor in Endotoxin-Induced Release of Monocyte Chemoattractant Protein 1 and Macrophage Inflammatory Protein 1β in Chimpanzees

A platelet-activating factor receptor antagonist reduced the release of macrophage inflammatory protein 1β (MIP-1β) during endotoxemia in chimpanzees but did not influence the secretion of monocyte chemoattractant protein 1 (MCP-1). Anti-tumor necrosis factor alpha monoclonal antibody completely prevented MCP-1 release and simultaneously enhanced the secretion of MIP-1β. Levels of MIP-1β and MCP-1 release were differentially regulated during endotoxemia.