Role of suppressor of cytokine signaling in ocular allergy

PURPOSE OF REVIEW: The goal of this article is to evaluate developments in the knowledge of suppressor of cytokine signaling (SOCS) protein ocular allergy and the potential of SOCS proteins as targets for therapeutic strategies. RECENT FINDINGS: The family of proteins designated SOCS proteins plays an important role in Th2-mediated allergic responses through the control of the balance between Th1 and Th2 cells. SOCS3 and SOCS5 are predominantly expressed in Th2 and Th1 cells, respectively, and they reciprocally inhibit the Th1 and Th2 differentiation processes. SOCS3 is highly expressed at the disease site of allergic conjunctivitis, and T-cell-specific expression of SOCS3 deteriorates clinical and pathological features of allergic conjunctivitis. Reduction of the expression level or inhibition of function clearly reduces the severity of allergic conjunctivitis. On the other hand, constitutive expression of SOCS5, a specific inhibitor of IL-4 signaling, results in reduced eosinophil infiltration. Moreover, negative regulation of the Th2-mediated response by dominant-negative SOCS3 and SOCS5 reduced the incidence of allergic conjunctivitis in a mouse model. SUMMARY: The present article summarizes recent findings in terms of a role of SOCS protein as a negative regulator in ocular allergy and its clinical application.