Immunomodulatory effects of galectin-1 on an IgE-mediated allergic conjunctivitis model.

Purpose: Galectin (Gal)-1, a lectin found at sites of immune privilege with critical role in the inflammation, has been poorly investigated in the ocular inflammatory diseases. Here, we evaluated the therapeutic potential of Gal-1 in ocular allergy using a model of ovalbumin (OVA)-induced AC.

Methods: OVA-immunized BALB/c male mice were challenged with eye drops containing OVA on days 14 through 16 with a subset of animals pretreated intraperitoneally with recombinant Gal-1 (rGal-1) or dexamethasone (Dex).

Results: Recombinant Gal-1 and Dex administration on days 14 through 16 was effective in reducing the clinical signs of allergic conjunctivitis (AC), plasma anti-OVA IgE levels, Th2 (IL-4 and IL-13), and eotaxin/RANTES levels in the lymph nodes. Four hours after the last OVA challenge, rGal-1 markedly increased Gal-1 endogenous levels in the conjunctiva, and provoked eosinophilia, which persisted at 24 hours. Recombinant Gal-1 had no effect on eosinophil activation, as evidenced by the similar pattern of peroxidase eosinophil expression between cells of rGal-1-treated and untreated AC groups. Conjunctival migrated eosinophils and neutrophils exhibited high levels of Gal-1 and β2-integrin, with points of colocalization, in the rGal-1-treated groups. These different effects observed for rGal-1 were correlated with elevated levels of activated ERK and p38 at 4 hours, and diminished levels of activated JNK and p38 at 24 hours in the eyes.

Conclusions: Gal-1 has an important role in ocular allergic inflammation and represents a potential target for the development of new therapeutic strategies in eye diseases.