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Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes
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Phorbol esters alter alpha4 and alphad integrin usage during eosinophil adhesion to VCAM-1
Matsuo Kikuchi1, Hiroshi Tachimoto, Esra Nutku
1Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
Cell Communication & Adhesion
|December 12, 2003
Summary
Phorbol-12-myristate-13-acetate (PMA) alters human eosinophil adhesion molecule expression and binding to VCAM-1. PMA affects alpha4 and alphad integrin roles in eosinophil attachment under static and flow conditions.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Eosinophils play a role in allergic inflammation.
- Integrins mediate cell adhesion, crucial for eosinophil function.
Purpose of the Study:
- To investigate the impact of phorbol-12-myristate-13-acetate (PMA) on human eosinophil adhesion molecules.
- To determine how PMA affects eosinophil attachment to VCAM-1 via alpha4 and alphad integrins under static and flow conditions.
Main Methods:
- Flow cytometry was used to assess surface expression of integrins.
- Eosinophil adhesion assays were performed under static and flow conditions.
- Monoclonal antibodies (mAbs) against alpha4 and alphad integrins were used to block adhesion.
Main Results:
- PMA increased surface expression of alphad integrins and decreased alpha4 integrin expression.
- Under static conditions, eosinophils primarily used alpha4beta1 integrins, but PMA-stimulated cells showed temperature- and cation-dependent adhesion to VCAM-1 and albumin, independent of beta1/beta2 integrins.
- Under flow conditions, PMA reduced eosinophil binding to VCAM-1, with both alpha4 and alphad mAbs equally inhibiting adhesion.
Conclusions:
- PMA significantly alters eosinophil integrin expression profiles.
- The relative importance of alpha4 and alphad integrins in eosinophil adhesion to VCAM-1 is modulated by PMA.
- PMA-induced changes in integrin expression affect eosinophil adhesion mechanisms under different physical conditions.
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