Fig. 6

Sympathetic breakdown of mucosal tolerance favors an allergic conjunctival reaction in the opposite ocular surface. a Experimental design for dissecting the inter-eye neurogenic inflammatory reflex contribution to development of ocular allergy. On day 1, a TRPV1 blocker (aTRPV1, SB-366791) was administered repeatedly to the right eye and/or a substance P blocker (aNK1R) was repeatedly applied on the left eye of mice 1 h before inducing a corneal burn in the right eye. Antigen (OVA) was instilled on the left eye from days 2 to 5, and then s.c. immunization (Imm) was performed with OVA+alum. Starting on day 21, mice were challenged daily with OVA on both eyes for 10 consecutive days. b Clinical score of ocular allergic response graded 20 min after challenge every 2 days. Control mice (Imm) only received OVA+alum s.c. before ocular antigen challenge on day 21, whereas OVA mice were tolerized by topical OVA administration to the left eye on days 2–5 before immunization. Burn, aTRPV1+Burn, and aNK1R+Burn mice had a corneal burn induced in the right eye on day 1 and received either saline or said antagonist in the corresponding eye, as detailed in a. Pooled data (mean ± SD) of 3 experiments with 4–6 mice/group (two-way ANOVA with Dunnett’s multiple comparisons test against OVA group). c OVA-specific IgE levels in sera obtained from mice on day 30 of experiment a, as assessed by indirect ELISA. Sera from control mice (gray dots) is included for reference. Pooled data (mean ± SD) of 3 experiments with 4–6 mice/group (one-way ANOVA with Dunnett’s multiple comparisons test against OVA group). d Representative photographs of mouse eyes obtained 20 min after OVA challenge on day 8. For all panels, asterisk (*) indicates a statistically significant difference by the corresponding test