Chapter 17 - Mucosal Regulatory System for Balanced Ocular Immunity

Abstract

The ocular surface is continually exposed to the external environment, yet the default regulation of this mucosal site involves immune privilege to maintain normal vision. Many regulatory mechanisms work together to create an immunological balance that suppresses inflammation and limits microbial growth in the ocular surface mucosa to preserve the visual axis. However, the ocular surface mucosa remains vulnerable to a variety of pathogens that can break immune tolerance and provoke substantial ocular immunopathology. The coordinated mechanisms that govern immune privilege but drive pathology in the eye present a distinct conundrum for vaccine development: how to amplify the immune system in the ocular mucosa without provoking visual morbidity? Even short-lived inflammatory events in the eye can have deleterious visual outcomes. This chapter reviews the organization and immunology of the ocular surface mucosa, common ocular pathogens, and current strategies guiding ocular vaccine development for two of the leading infectious causes of blindness worldwide: Chlamydia trachomatis and herpes simplex virus type 1. While the ocular mucosa is now a common delivery route for vaccines against diseases of veterinary and agricultural importance, this chapter will focus on human pathogens and their impact on vision.