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Human polymorphonuclear neutrophils express a B7-1-like molecule
A Windhagen1, S Maniak, A Gebert
1Department of Neurology, Medical School Hannover, Germany. Windhagen.Anja@MHHannover.de
Abstract:
Polymorphonuclear neutrophils (PMN) are part of the innate immune system and are first-line effector cells in acute inflammatory responses. On activation PMNs secrete cytokines and oxygen metabolites that might be involved in the regulation of the acquired immune response. We show here that peripheral blood PMNs constitutively express a B7-1-like molecule as detected by immunostaining with several B7-1 antibodies. Reverse transcriptase-polymerase chain reaction using three sets of primers spanning different regions of B7-1 indicate dissimilarities at the mRNA level. B7-1 mRNA is expressed in bone marrow cells and lipopolysaccharide (LPS)-stimulated but not in unstimulated PMNs. The B7-1-like molecule is localized to the cytoplasmic granules and translocated to the cell surface after stimulation with LPS or interleukin-12 in some donors. Binding of CTLA4-Ig suggests that the B7-1-like molecule can interact with functional B7 ligand and might be important in the immunobiology of PMNs.
Insights
Peripheral blood neutrophils (PMNs) express a B7-1-like molecule. This molecule, found in granules, moves to the cell surface upon stimulation, potentially regulating immune responses.
Area of Science:
- Immunology
- Cell Biology
Background:
- Polymorphonuclear neutrophils (PMNs) are key innate immune cells involved in acute inflammation.
- Activated PMNs release mediators that may influence the adaptive immune response.
Purpose of the Study:
- To investigate the expression and function of a B7-1-like molecule on human peripheral blood PMNs.
- To determine the cellular localization and regulation of this molecule.
Main Methods:
- Immunostaining using B7-1 antibodies.
- Reverse transcriptase-polymerase chain reaction (RT-PCR) for B7-1 mRNA.
- Stimulation of PMNs with lipopolysaccharide (LPS) and interleukin-12 (IL-12).
- Flow cytometry and CTLA4-Ig binding assays.
Main Results:
- Peripheral blood PMNs constitutively express a B7-1-like molecule on the protein level.
- B7-1 mRNA expression differs between bone marrow cells and PMNs, and is upregulated by LPS in PMNs.
- The B7-1-like molecule is stored in cytoplasmic granules and translocates to the cell surface upon stimulation.
- The molecule binds CTLA4-Ig, indicating functional interaction with B7 ligands.
Conclusions:
- Human peripheral blood PMNs express a B7-1-like molecule with functional relevance.
- This molecule's translocation upon stimulation suggests a role in PMN-mediated immune regulation.
- The findings highlight a novel aspect of PMN immunobiology and their interaction with adaptive immunity.