Topical/mucosal delivery of sub-unit vaccines that stimulate the ocular mucosal immune system

Mucosal vaccination is proving to be one of the greatest challenges in modern vaccine development. Although ocular mucosal immunity is highly beneficial for achieving protective immunity, the induction of ocular mucosal immunity against ocular infectious pathogens, particularly herpes simplex virus type 1 (HSV-1), which is the leading cause of infectious corneal blindness, remains difficult. Recent developments in cellular and molecular immunology of the ocular mucosal immune system (OMIS) may help in the design of more effective and optimal immunization strategies against ocular pathogens. In this review, we highlight ocular mucosal immunoprophylactic and immunotherapeutic vaccine strategies that have been evaluated to control the many pathogens that attack the surface of the eye. Next, we describe the current understandings of the OMIS and elucidate the structure and the function of the humoral and cellular immune system that protects the surface of the eye. Results from our recent experiments using topical ocular delivery of peptides-CpG and lipopeptide-based vaccines against HSV-1 infection are presented. The future challenges and issues related to the ocular mucosal delivery of molecularly defined sub-unit vaccines are discussed.