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Updated: Jul 11, 2026

Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes
09:14

Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes

Published on: June 13, 2014

Cell spreading distinguishes the mechanism of augmentation of T cell activation by integrin-associated protein/CD47

M I Reinhold1, J M Green, F P Lindberg

  • 1Division of Infectious Diseases, Washington University School of Medicine, Box 8051,660 South Euclid Avenue, St Louis, MO 63110, USA.

International Immunology
|May 18, 1999
PubMed

Integrin-associated protein (IAP/CD47) is a 50 kDa transmembrane protein initially defined as a regulator of beta3 integrin-mediated functions in neutrophils. IAP also can synergize with the TCR in T cell activation independent of beta3 integrins. To analyze the mechanism for IAP synergy with TCR, we expressed in Jurkat cells a chimeric molecule, consisting of the CD16 extracellular domain, the CD7 transmembrane domain and the TCR zeta chain cytoplasmic tail (CD16-7-zeta), which on its own is unable to induce IL-2 production. Ligation of IAP acted in synergy with TCR to induce IL-2 transcription and synthesis, but failed to synergize with the signal generated by CD16-7-zeta, while CD28 was a potent co-stimulator with both TCR and CD16-7-zeta. The failure of IAP to activate Jurkat together with CD16-7-zeta correlated with a lack of c-Jun N-terminal kinase, but not extracellular-signal-regulated kinase activation. Jurkat adhesion to anti-IAP, but not anti-CD28, induced cell spreading and the same domains of IAP required for augmentation of T cell activation were required to induce cell spreading. IAP synergy with TCR signaling likely results from its ability to stimulate adhesion to a ligand-expressing surface or antigen-presenting cell (APC), rather than from initiation of a novel signaling cascade. We conclude that a major role for ligation of IAP in T cell activation is to enhance the efficiency of TCR signaling by causing T cells to spread on an APC or surface.

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