Location: Animal Parasitic Diseases
Title: Both host and parasite MIF molecules bind to chicken macrophages via CD74 surface receptor Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 10, 2013
Publication Date: N/A
Technical Abstract: Macrophage migration inhibitory factor (MIF) is recognized as a soluble factor produced by sensitized T lymphocytes and inhibits the random migration of macrophages. Recent research shows a more prominent role of MIF as a multi-functional cytokine mediating both innate and adaptive immune responses. Our group has identified both chicken and Eimeria MIF, and characterized its molecular function in enhancing innate immune responses during inflammation. In this study, we report that chicken CD74 (ChCD74), a type II transmembrane protein, functions as a macrophage surface receptor that binds to MIF molecules. The results of flow cytometry and fluorescent microscopy showed that incubation of macrophages with recombinant chicken MIF (rChMIF) led to binding of rChMIF on the surface of HTC cells. To verify that ChCD74 acts as a surface receptor for MIF molecules, the recombinant form of ChCD74 (rChCD74) was transiently overexpressed with green fluorescent protein at its N-terminus in HEC cells. Fluorescence analysis showed that incubation of HTC cells transiently over-expressing rChCD74 with rChMIF showed co-localization of the two molecules. The close interaction of rChCD74 and rChMIF was corroborated by immunoprecipitation assay. Since Eimeria sp. also produce and secrete Eimeria MIF (EMIF) molecules during infection, we examined the binding of rEMIF to chicken macrophages via ChCD74. Our analysis showed binding of rEMIF to chicken macrophages via rChCD74 as a surface receptor. Together, this study provides conclusive evidence that both host and parasite MIF molecules bind to chicken macrophages via the surface receptor ChCD74.