Quantification of soluble Ova (sOVA) concentration in serum was performed by Ova-specific ELISA. Microtiter plates were coated with polyclonal rabbit anti-Ova antibodies (1:3000 dilution, Ray-Biotech) and bound sOVA was detected using biotinylated rabbit polyclonal anti-Ova antibodies (1:5000 dilution, Abcam) and streptavidin-peroxidase (1:15000, Roche).