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Neutrophil beta-2 microglobulin: an inflammatory mediator
O W Bjerrum1, M H Nissen, N Borregaard
1Department of Medicine and Haematology L, State University Hospital, Copenhagen, Denmark.
Scandinavian Journal of Immunology
|September 1, 1990
Summary
Neutrophils release native Beta-2 microglobulin (beta 2m), a component of HLA class I, which lymphocytes can modify into Des-Lys58-beta 2m, potentially acting as an inflammatory messenger.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Beta-2 microglobulin (beta 2m) is the light chain of HLA class I antigens.
- Two forms exist: native beta 2m and proteolytically modified Des-Lys58-beta 2m.
- Mononuclear cells modify native beta 2m; Des-Lys58-beta 2m enhances interleukin-2 production.
Purpose of the Study:
- Investigate the presence and release of native beta 2m in human neutrophils.
- Determine if neutrophils participate in the modification of beta 2m.
- Clarify the role of lymphocytes in beta 2m modification.
Main Methods:
- Immunofluorescence and subcellular fractionation to locate beta 2m in neutrophils.
- Stimulation assays (chemotactic agents, phorbol ester) to induce beta 2m release.
- Co-culture experiments with neutrophils and lymphocytes to study beta 2m modification.
Main Results:
- Human neutrophils store native beta 2m in specific granules, secretory vesicles, and plasma membrane.
- Native beta 2m is released from neutrophils upon stimulation.
- Neutrophils do not proteolytically modify beta 2m; lymphocytes transform native beta 2m to Des-Lys58-beta 2m post-degranulation.
Conclusions:
- Neutrophil-derived beta 2m, after exocytosis, can be converted to Des-Lys58-beta 2m by lymphocytes.
- This transformation suggests a role for modified beta 2m as an extracellular messenger in inflammatory foci, mediating communication between granulocytes and lymphocytes.