ICAM-1/LFA-1 interactions in T-lymphocyte activation and adhesion to cells of the blood-retina barrier in the rat.
To identify the signals involved in the adhesion and subsequent migration of lymphocytes across the endothelium (REC) and pigment epithelium (RPE) of the blood-retina barrier we have studied the effects of monoclonal antibodies (mAb) to rat adhesion/accessory molecules on the binding of normal and concanavalin A (Con A)-activated rat spleen lymphocytes to cultured unstimulated and interferon-gamma (IFN-gamma)-stimulated RPE and REC. Forty to 48% of unactivated T cells were found to bind to normal REC or RPE by leucocyte function-associated antigen-1/intercellular adhesion molecule-1 (LFA-1/ICAM-1)-independent mechanisms, despite constitutive expression of ICAM-1 by the RPE cells and LFA-1 by the T cells. Con A-activated lymphocytes showed an enhanced adhesion to both RPE and REC. However, IFN-gamma-stimulated RPE and REC did not demonstrate a significant increase in adhesiveness for normal lymphocytes highlighting the importance of lymphocyte integrin activation from low-affinity to high-affinity state. Activated lymphocyte adhesion to unstimulated RPE and REC was significantly blocked by LFA-1 mAb (35%, P < 0.0001) and ICAM-1 mAb (20%, P < 0.001). Inhibition of adhesion by antibody to CD2 was not significant. Both ICAM-1 and LFA-1 mAb also significantly (P < 0.05) blocked antigen presentation following retinal extract stimulation of lymphocytes from immunized rats in proliferation assay. These data suggest that the ICAM-1/LFA-1 system is important in lymphocyte trafficking into the eye only after lymphocyte activation.
Mesri
M
M
Department of Ophthalmology, University of Aberdeen Medical School, Foresterhill, UK.
Liversidge
J
J
Forrester
J V
JV
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001813:Blood-Retinal Barrier / Q000276:immunology*; D002448:Cell Adhesion / Q000276:immunology; D002478:Cells, Cultured; D003208:Concanavalin A / Q000276:immunology; D004730:Endothelium, Vascular / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis / Q000276:immunology*; D007371:Interferon-gamma / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000276:immunology*; D010857:Pigment Epithelium of Eye / Q000276:immunology; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D016169:Lymphocyte Function-Associated Antigen-1; D003208:Concanavalin A; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma