Abstract
Abstract: :
Purpose: Experimental autoimmune uveitis is an animal model for endogenous human posterior uveitis. The complement system is a component of innate immunity and functions in the mediation of inflammatory responses, chemotaxis, defense against pyogenic bacterial infection, and bridging innate and adaptive immunity. Most of the functions of complement are mediated by cleavage products of C3 and C5. We have previously shown that eye-specific transgenic overproduction of a soluble complement inhibitor reduces the severity and incidence of EAU in mice. We now examine whether mice genetically deficient for C3 show similar findings. Methods: A well characterized mouse strain, deficient for C3, was used. Briefly, embryonic stem cells were transfected with a linearized vector targeting exon 1 of C3. Homologous recombinants were injected into C57BL/6 blastocysts. Chimeric males were mated with C57BL/6 females and F1 heterozygous mice inbred to produce homozygous C3-deficient mice. EAU was induced via an established model, using 500µg per animal of a synthetic peptide of amino acid residues 1-20 (GPTHLFQPSLVLDMAKVLLD) of human interphotoreceptor retinoid-binding protein in complete Freund’s adjuvant supplemented with Mycobacterium tuberculosis strain H37RA (2.5 mg/ml), injected subcutaneously, concurrent with 1.5 µg per animal of pertussis toxin IP. Eyes were enucleated at day 21 and either fixed in 10% neutral buffered formalin and paraffin embedded or snap frozen in OCT. Sections were stained with H&E. Disease severity was assessed in a masked fashion, using a scale of 0 to 4. An average severity score was calculated for each eye of each animal, and then a single value obtained by averaging the score from each eye. Results Conclusions: There is mounting evidence for complement’s role in ocular inflammatory disease. The current study adds further evidence to this theory by demonstrating that animals deficient in the C3 component of complement exhibit both a significantly decreased incidence and severity of EAU compared to their WT littermates. Comparison of Disease Incidence and Severity between Wildtype and C3 -/- mice
Keywords: uveitis-clinical/animal model • autoimmune disease • animal model