Objective       To identify bioactivity of anti-human macrophage migration inhibitory factor (hMIF) monoclonal antibody (mAb) F11

and to investigate its protective effect on sepsis mice.       Methods       Subclass

affinity and specificity of anti-hMIF mAb F11 were analyzed by ELISA

Western blotting and immunohistochemistry. Bioactivity of mAb F11 was identified by nitric oxide (NO) release inhibition test in MIF-stimulated RAW264.7 cells and tautomerase activity inhibi

tion test. Protective effect of mAb F11 and its effect on serum levels of TNF-α and IL-6 were determined in C57BL/6J mice model of sepsis.       Results      The mAb F11 was of IgG1 subclass

and its affinity was 2.50×10

10

. Western blotting and immunocytochemistry showed strong positive signals. In bioactivity research

mAb F11 significantly inhibited NO releasing from MIF-stimulated RAW264.7 cells as well as the activity of MIF tautomerase (P0.01). mAb F11 significantly improved the survival rate of sepsis mice (CLP model: P0.01; LPS model: P0.05) in a dose-dependent manner

and significantly suppressed the elevation of serum levels of TNF-α and IL-6 (P0.05).       Conclusion        Anti-MIF mAb F11 is successfully prepared

which has high specificity and affinity. The mAb F11 can inhibit activity of MIF tautomerase

significantly improve the survival rate of sepsis mice and reduce serum levels of TNF-α and IL-6.