Regulation of T cell proliferation by anti-CD49d and anti-CD29 monoclonal antibodies. Journal of leukocyte biology

Abstract: The j3 integrin VLA-4 (a4131, CD49d/CD29), which is expressed on a barge subpopulation of peripheral blood T lymphocytes, functions as a receptor for the en-dothebial adhesion protein VCAM-1 and the extracellular matrix protein fibronectin. Previous studies showed that immobilized fibronectin enhanced anti-CD3 monoclonal antibody (mAb)-induced T cell proliferation through binding to the integrins VLA-4 and VLA-5 (cx5i3i, CD49eICD29). We studied the ability of the anti-CD49d mAb L25 to potentiate proliferation. T cell proliferation was induced by subthreshold concentrations of anti-CD3 mAb (mAb OKT3) coimmobilized with mAb L25 but not with coimmobilized anti-CD29 (flu) mAb. Soluble anti-CD29 mAb inhibited the proliferation induced by coim-mobilized mAb OKT3 and L25 but not proliferation in-duced by mAb OKT3 with PMA or coimmobilized anti