LYMPHOCYTE MIGRATION THROUGH CULTURED ENDOTHELIAL-CELL MONOLAYERS DERIVED FROM THE BLOOD-RETINAL BARRIER

Lymphocyte migration across endothelial monolayers, derived from the r at blood-retinal barrier, was recorded in vitro using time-lapse video microscopy. Syngeneic lymphocytes were plated out onto endothelial ce ll monolayers for 4 hr and their surface motility and transmonolayer m igration recorded and quantified. Under resting conditions lymphocytes , obtained from peripheral lymph nodes (PLN), were small, rounded and static with less than 5% migrating across the monolayer. Activation of the lymphocytes with concanavalin A (Con A) increased their size and surface motility on both interferon-gamma (IFN-gamma)-treated and rest ing endothelia, but did not alter the number migrating across the mono layer. Similar results were also found for phytohaemagglutinin (PHA)-a ctivated lymphocytes. Interleukin-2 (IL-2)-dependent CD4+ T-cell lines specifically recognizing either retinal soluble antigen (S-Ag) or bov ine serum albumin (BSA) exhibited significantly greater surface motili ty over the endothelial monolayers than the mitogen-activated PLN lymp hocytes. By 4 hr, in excess of 50% of the T-cell line lymphocytes had migrated across the endothelial monolayer. Treatment of the endothelia l cells with IFN-gamma caused a small, but not significant, increase i n the level of T-cell line lymphocyte migration. These results suggest that the migration of lymphocytes across central nervous system-deriv ed endothelia is primarily dependent upon the state and mode of lympho cyte activation.