Tear film hyperosmolarity disrupts the immune tolerance of the ocular surface: a potential initiator of dry eye?

GUZMAN M; KEITELMAN I; SABBIONE F; TREVANI, AS; GIORDANO, M; GALETTI J

Congreso; Reunión Anual de la SAI; 2014

Sociedad Argentina de Inmunología y Soc. Argentina de Investigación Clínica

Tear film hyperosmolarity is commonly observed in dry eye, but its exact role in the pathogenesis of this ocular surface disorder is unknown. A localized form of autoimmune disease, dry eye involves disruption of the ocular surface?s immune homeostasis, but the sequence of events that initiates it is unclear. Objective: To assess conjunctival immune tolerance in a murine model of hyperosmolarity stress. Study design: 8- to 12-week-old female Balb/c mice were instilled isoosmolar (0.3 Osm) or hyperosmolar (3 Osm) saline on both eyes 3 times daily for 5 days. Ovalbumin (OVA) was instilled on both eyes at different time points. After subcutaneous immunization with OVA in adjuvant (day 8), induced T cell responses were measured by the delayed-type hypersensitivity (DTH) response in the footpad (day 15). In some experiments, the T cells in draining lymph nodes (day 5) were evaluated by flow cytometry. Supernatants from Pam212 epithelial cells exposed to iso- or hyperosmolar medium were assayed in a phagocytosis assay with the Raw 2647 macrophage cell line. Results: Compared to non-instilled immunized mice, OVA-instilled mice developed reduced DTH responses, as did their OVA+isoosmolar saline-instilled cage mates (p