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2B4 (CD244) is expressed and functional on human eosinophils.
Ariel Munitz1, Ido Bachelet, Shira Fraenkel
1Department of Pharmacology, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel.
Journal of Immunology (Baltimore, Md. : 1950)
|December 22, 2004
Summary
Human eosinophils express the 2B4 receptor, a finding that suggests a broader role for these immune cells in various diseases. This discovery opens new avenues for understanding eosinophil function in health and illness.
Area of Science:
- Immunology
- Cell Biology
- Hematology
Background:
- Eosinophils are implicated in parasitic, allergic, immunological, and malignant disorders, but their precise roles are often unclear.
- Eosinophil activation can be triggered by various agonists, including immunoglobulins, lipid mediators, and cytokines.
- Surface phenotyping of eosinophils may elucidate their functions in diverse pathophysiological contexts.
Purpose of the Study:
- To investigate the surface receptor expression profile of human peripheral blood eosinophils.
- To determine the functional consequences of expressing specific surface receptors on eosinophils.
- To explore the potential role of eosinophils in immune responses and disease pathogenesis.
Main Methods:
- Screening of eosinophils using a panel of antibodies against CD2 subfamily receptors via flow cytometry (FACS).
- Investigating the release of eosinophil peroxidase, IFN-gamma, and IL-4 following cross-linking of the 2B4 receptor.
- Assessing eosinophil-mediated cytotoxicity against malignant cell lines (P815 and 721.221) after 2B4 activation.
- Analyzing intracellular signaling pathways, including ERK and tyrosine phosphorylation, upon receptor activation.
Main Results:
- Human peripheral blood eosinophils, but not basophils or neutrophils, express the NTB-A receptor.
- Eosinophils were found to express 2B4, CD84, CD58, and CD48, but not Signaling Lymphocytic Activation Molecule (SLAM) or CD2.
- Cross-linking of 2B4 on eosinophils induced the release of eosinophil peroxidase, IFN-gamma, and IL-4.
- Activation of eosinophils via 2B4 resulted in significant eosinophil-mediated cytotoxicity against mouse mastocytoma P815 and EBV-infected 721.221 B cell lines.
- Eosinophil activation through 2B4 or pervanadate treatment led to ERK and tyrosine phosphorylation, respectively.
- Eosinophils were shown to express slam-associated protein.
Conclusions:
- Human eosinophils express a functional 2B4 receptor.
- The expression of 2B4 on eosinophils suggests a broader and more significant role for these cells in immune responses and various diseases.
- This finding opens new possibilities for understanding eosinophil involvement in conditions ranging from allergies to malignancies.