Selective upregulation of a functional β<sub>7</sub> integrin on differentiating eosinophils

Background: The sequence of adhesion‐molecule expression during eosinophil differentiation remains unclear. Methods: We analyzed the surface expression of α4, β1, and β7 integrins and compared it to established myeloid developmental markers, using the eosinophilic cell line HL‐60 clone 15, as well as cord and peripheral blood differentiation assays. Results: Cells induced to eosinophil differentiation by treatment with butyric acid, IL‐5, and GM‐CSF showed a significant upregulation of β7 integrin expression coincident with a marked upregulation of CD35 and attenuation of CD33 and β1 integrin expression. In addition, adhesion of induced HL‐60 clone 15 cells to fibronectin was attenuated by a β7 integrin antibody. Conclusions: Our data show that protein synthesis‐dependent upregulation of the functional β7 integrin occurs under conditions when α4 and β1 integrins are fully expressed, indicating a sequential appearance of specific adhesion molecules on differentiating eosinophil progenitors.

Selective upregulation of a functional β₇ integrin on differentiating eosinophils Journal Articles