Induction of homotypic T cell adhesion by triggering of leukocyte function-associated antigen-1α (CD11a): differential effects on resting and activated T cells
✍ Scribed by Gerrit Koopman; Steven T. Pals; Michael de Graaff; Anita C. L. M. Huysmans; Chris J. L. M. Meijer
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 689 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0014-2980
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✦ Synopsis
Abstract
The leukocyte integrin LFA‐1 (CD11a/CD18) plays a key role in many adhesive interactions involving cells of the immune system. Recently, it has been shown that LFA‐1 is not only involved in cell adhesion, but that stimulation of LFA‐1 can also contribute to cell activation. We now demonstrate that triggering of LFA‐1 on T lymphocytes by monoclonal antibodies (mAb) against the LFA‐1α chain, but not against the LFA‐1β chain, promotes cell adhesion. Induction of homotypic adhesion was only observed in T cells that had been pre‐activated with anti‐CD3 and not in resting peripheral blood T lymphocytes. The induced homotypic adhesion is mediated by LFA‐itself, because it was inhibited by anti‐LFA‐1β mAb. This notion is supported by the temperature and divalent cation dependence which is characteristic of LFA‐1‐mediated adhesion. mAb against ICAM‐1 (CD54) did not block LFA‐1α‐induced adhesion. The sensitivity of LFA‐1α‐induced adhesion to H7, which prevents the activation of protein kinase C and protein kinase A, and to cytochalasin B, which inhibits microfilament formation, suggests that the activation of the LFA‐1 pathway through the LFA‐1α chain involves cell activation and requires an intact cytoskeleton.