The role of cellular immunity both in the induction and effector phases of experimental allergic...

In allergic conjunctivitis, the early phase reaction has been studied extensively both in humans and animals. Although cellular infiltration is the main feature of the late phase reaction, the role of cellular immunity remains unclear. The purpose of this study was to elucidate the role of cellular immunity both in the induction and effector phases of experimental allergic blepharoconjunctivitis (EAC). To analyse the involvement of cellular immunity in the induction phase, 6-8-week-old male Lewis rats were immunized with ovalbumin (OVA) emulsified with complete Freund's adjuvant (CFA), incomplete Freund's adjuvant (IFA), TiterMaxR (TM), aluminum hydroxide [Al(OH)3], or without any adjuvant. Three weeks after immunization, the rats were challenged with OVA by eye drops, and 24 hr later they were euthanized and their eyes, including the lids, blood, and lymph nodes were harvested for analysis of disease and immune responses. The results indicated that adjuvants were necessary to induce disease as well as both cellular and humoral immunity. Al(OH)3, CFA and TM induced stronger disease and cellular immunity than IFA. The intensity of disease correlated with that of cellular immunity. To further investigate the involvement of cellular immunity in EAC, lymph node cells collected from immunized rats were adoptively transferred into naive syngeneic recipients that were challenged 4 days later with OVA. EAC developed in the recipients of lymph node cells that were also stimulated in culture with OVA. These recipient rats developed cellular infiltration in the lid and conjunctiva, in a dose-dependent manner. These results suggest that cellular immunity played a major role in the development of EAC, both in the induction and effector phases.