The adjuvant Labrafil M2125 CS Enhances The Therapeutic induction of Oral Tolerance in the Experimental Autoimmune Uveitis

Abstract

Purpose: : The oral administration of retinal antigens can treat ocular inflammation in animal. A new adjuvant, Labrafil M 2125 CS, A non-aqueous excipient, has been shown to enhance the oral tolerogenic effect of retinal S antigen peptide, PDSAg (using aa .341-354) in the experimental autoimmune uveitis (EAU) rat model. The goal of this study was to evaluate the adjuvant effect of Labrafil M2125 CS in the induction of oral tolerance with the uveitogenic HLA class I peptide B27PD, (which also shares amino acid homology with PDSAg ) in the rat model of EAU.

Methods: : EAU in Lewis female rats was induced by immunizing with 100ug PDSAg emulsified with complete Freund’s adjuvant. Feeding began three days prior to immunization, and were fed every other day until the day of sacrifice. There were five groups: B27PD emulsified with 2% Labrafil M 2125 CS; PDSAg emulsified with 2% Labrafil M 2125 CS; B27PD alone; PDSAg alone and PBS alone. Rats were sacrificed on day 16 after immunization. and eyes were enucleated for histopathological scoring. Draining lymph nodes were excised for immune marker staining.

Results: : The orally administered B27PD with 2% Labrafil M2125 CS reduced by 23% the EAU scores as compared to B27PD alone. Labrafil M2125 CS did change PDSAg induced oral tolerogenic effect. No persistant alterations in T cell subgroup numbers were seen.

Conclusions: : Our results suggest that oral adjuvants are well tolerated and could be used to enhance orally induced immune tolerance in EAU and possibly in human .

Keywords: inflammation