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Purification and partial biochemical characterization of a human monocyte-derived, neutrophil-activating peptide that
J M Schröder1, U Mrowietz, E Morita
1Department of Dermatology, University of Kiel, Federal Republic of Germany.
Abstract:
A novel monocyte-derived neutrophil-activating peptide (MONAP) produced by lipopolysaccharide- and phorbol myristate acetate-stimulated human peripheral blood monocytes was purified by sequential ion exchange-high performance liquid chromatography (HPLC), size exclusion HPLC, and reversed phase HPLC. Biologic activities of the purified cytokine were monitored by either an enzyme release assay or a chemotaxis assay, using peripheral human neutrophils. Purified MONAP was found to be homogeneous, giving a single peak on size-exclusion HPLC, reversed-phase HPLC, as well as a single 10-kDa band on silver-stained polyacrylamide gels. Purified MONAP stimulate human neutrophil chemotaxis at an estimated molarity of 5 x 10(-11) M. Half-maximal enzyme release of cytochalasin B pretreated neutrophils occurred at 2 to 3 x 10(-10) M, whereas superoxide anion production elicited by various concentrations of MONAP was found to be low. Isolated human peripheral monocytes, as well as human eosinophils, showed no chemotactic response to MONAP, indicating neutrophil specificity. MONAP activity was separated from thymocyte-stimulating activity by reversed-phase HPLC, indicating nonidentity with interleukin (IL)-1. This was further supported by heat resistance of MONAP, which is in contrast to the heat sensitivity of IL-1. In addition, IL-1 obtained as a by-product during isolation of MONAP did not stimulate human neutrophil chemotaxis.
Insights
Researchers purified a novel monocyte-derived neutrophil-activating peptide (MONAP) that specifically activates human neutrophils. This cytokine demonstrates potent chemotaxis and enzyme release, distinguishing it from interleukin-1.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Human peripheral blood monocytes produce various signaling molecules.
- Lipopolysaccharide (LPS) and phorbol myristate acetate (PMA) are potent stimulators of monocyte activation.
- Neutrophils play a critical role in innate immunity and host defense.
Purpose of the Study:
- To purify and characterize a novel neutrophil-activating peptide from stimulated human monocytes.
- To determine the biological activities and specificity of the purified peptide.
- To differentiate the novel peptide from known cytokines like Interleukin-1 (IL-1).
Main Methods:
- Sequential purification using ion exchange, size exclusion, and reversed-phase High-Performance Liquid Chromatography (HPLC).
- Assessment of biological activity via neutrophil enzyme release and chemotaxis assays.
- Analysis of purity and molecular weight using HPLC and polyacrylamide gel electrophoresis.
Main Results:
- A novel monocyte-derived neutrophil-activating peptide (MONAP) was purified to homogeneity (10 kDa).
- MONAP induced significant human neutrophil chemotaxis at 5 x 10(-11) M and enzyme release at 2-3 x 10(-10) M.
- MONAP exhibited neutrophil specificity, with no chemotactic response observed in monocytes or eosinophils.
- MONAP was distinguished from IL-1 based on heat resistance and differential HPLC behavior.
Conclusions:
- A novel cytokine, MONAP, specifically activates human neutrophils.
- MONAP represents a distinct signaling molecule involved in neutrophil recruitment and activation.
- The findings provide insights into monocyte-neutrophil communication pathways in immune responses.