Purification of thymic macrophage migration inhibitory factor (MIF)

Area of Science:

• Immunology
• Biochemistry
• Cell Biology

Background:

• Thymus extracts from immunologically challenged animals contain Macrophage Migration Inhibitory Factor (MIF) activity.
• MIF plays a crucial role in immune responses by modulating macrophage behavior.

Purpose of the Study:

• To purify and characterize the MIF found in thymus extracts.
• To elucidate the functional properties of purified MIF, including its effects on macrophage activation and potential enzymatic activities.

Main Methods:

• Purification involved ethanol precipitation, ultrafiltration, isoelectric focusing, and preparative acrylamide gel electrophoresis.
• Characterization included polyacrylamide-gel electrophoresis, SDS-gel electrophoresis, and assessment of lability to enzymes and heat.

Main Results:

• A homogeneous MIF with a molecular weight of 36,000 daltons was isolated.
• The purified MIF was trypsin- and neuraminidase-labile, thermostable, and exhibited pH-dependent degradation and reassembly.
• MIF activated macrophages phagocytically but was not chemotactic or proteolytic.

Conclusions:

• The study successfully purified and characterized thymus-derived MIF.
• Purified MIF possesses specific macrophage-activating properties relevant to immune function.
• MIF's biochemical properties and functional activities were elucidated, contributing to understanding immune regulation.