Abstract
Purpose :
Interaction of the integrin ICAM-1 with its ligand LFA-1 plays an important role in ocular surface inflammation. Lifitegrast ophthalmic solution 5% is an LFA-1 antagonist indicated for dry eye disease (DED) treatment. This study evaluated the effect of lifitegrast on ICAM-1/ LFA-1 binding required for immunological synapse (IS) formation and downstream T cell function.
Methods :
Both prevention of IS formation and disruption of existing IS were assessed. Peripheral blood mononuclear cells (PBMC) were isolated from 3 healthy donors. Autologous CD3+ T-cell and dendritic cell (DC) co-cultures were activated with staphylococcal enterotoxin B (SEB) in the presence or absence of lifitegrast at 3 different concentrations. An analog of lifitegrast (compound 4) was tested at maximum concentration. Presence of IS was evaluated by quantifying ICAM-1 and T-cell receptor (TCR) clustering on the surface of dendritic and T cells through immunofluorescence staining (anti-ICAM-1 and anti-CD3 antibodies) using confocal microscopy. To detect prevention of IS formation, PBMC were treated with SEB in the absence or presence of compound. To detect disruption of established IS, PBMC were stimulated with SEB prior to compound addition. IS assessments occurred after 20 minutes. The ratio of the number of DC to T cells (DC/T cell) and percentage of interacting cells were quantified. Flow cytometry was used to evaluate viable CD4+ or CD8+ T cell proliferation.
Results :
Lifitegrast caused a significant concentration-dependent increase in the DC/T cell ratio after 20 minutes, and a corresponding decrease in the percentage of interacting T cells following assessments of both IS formation and disruption (Figure 1A-B). Lifitegrast had a concentration-dependent inhibitory effect on SEB-driven PBMC, CD4+ and CD8+ T cell proliferation, without obvious cytotoxicity.
Conclusions :
These results provide evidence for the role of LFA-1 in IS formation between DC and T cells and its downstream effect on T-cell function. Furthermore, lifitegrast prevented IS formation as well as disruption leading to inhibition of T-cell function. This supports the characterization of lifitegrast as an anti-inflammatory agent in a T cell context.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.