Topical Leukocyte Function-Associated Antigen-1 (LFA-1) Antagonist Treatment (Lifitegrast) Suggest that Immune Synapsis and T cell Adhesion in Limbal Vessels is affected during DED

Abstract

Purpose : The leukocyte function-associated antigen-1 (LFA-1) binds to the intercellular adhesion molecule (ICAM) family, with its principal ligand being ICAM-1. ICAM-1/LFA-1 interaction is essential for T-cell activation as well as for migration of T-cells to target tissues.The purpose of this study was to assess if LFA-1 antagonist Lifitegrast can modulate T cell activation in the dLNs, subsequently affecting T cell migration to the ocular surface during DED Methods : DED was induced in 6-8 week old wild-type mice by exposure to the controlled environmental chamber and subcutaneous injections of scopolamine. Mice were treated with topical Lifitegrast (or normal saline [NS] control) 3 times daily. To asses clinical DED severity, corneal fluorescein score (CFS) was evaluated in both groups. Corneal T cells were quantified by flow cytometry of single cell suspensions at days 10, 15 and 21. T cells from NS-treated and Lifitegrast-treated DED mice were used as donors for adoptive transfer experiments to NS-treated DED mice (recipients). Protein levels of interleukin (IL)-1b, IL-6, IL-10, IL-17, interferon (IFN)-g, and tumor necrosis factor (TNF)-awere measured in tear samples using Bio-plex Results : Lifitegrast-treatment of DED mice resulted in significant reduction of CFS and in reduced corneal T cells as compared to the NS group by flow cytometry at days 15 and 21 (p<0.05). Limbal vascular sticking efficacy (adhesion) of donor T cells from a DED mice was increased in recipient DED mice at days 15 (62±12)% and 21 (54±6)%. Donor T cells from Lifitegrast-treated (9 ±4)% were comparable to T cells from naïve donor (5±3)% mice (p<0.001). The cytokines IFN-g (75±12) pg/ml, (52±14) pg/ml, (47±15) pg/ml and IL-17 (40±14) pg/ml, (37±9) pg/ml, (69±10) pg/ml were increased, in tears of NS-treated DED mice at days 10, 15 and 21 respectively. While they were reduced in Lifitegrast-treated DED mice (22 ±8) pg/ml, (18±12) pg/ml, (12±8) pg/ml and (10±4) pg/ml, (15±9) pg/ml, (18±8) pg/ml for IFN-g and IL-17 respectively (p<0.05) Conclusions : Lifitegrast treatment results in decreased corneal T cell migration and pro-inflammatory tear cytokines in DED. Adoptive transfer experiments suggest that topical Lifitegrast may be reaching dLN and potentially affecting T cell activation and subsequent T cell adhesion to limbal vessels.