Acid Stability of Anti-Helicobacter pyroli IgY in in Aqueous Polyol Solution

Abstract

IgY was separated from a hen's egg yolk that was immunized with Helicobacter pyroli. The anti-H. pyroli IgY activity at acidic pH and the suppressive effect of polyol on acid-induced inactivation of IgY were investigated. Sorbitol and xylitol were used as polyols. IgY was quite stable at pH 5-7. Irreversible inactivation of IgY was observed at pH below 4, and proceeded rapidly at pH below 3. The acid stability of IgY was enhanced in the presence of 30% sorbitol or above. In a 50% aqueous sorbitol solution, an acid-induced inactivation was almost completely suppressed at pH 3. However, the improvement of IgY activity was not observed in the aqueous xylitol solution. IgY showed almost the same activity as native IgY when sucrose was substituted for sorbitol. On the other hand, the xylitol replacement with sucrose did not enhance the acid stability of IgY. The acid-induced inactivation of IgY was related to tryptophyl fluorescence. Fluorescence emission spectra suggested that structural changes near the tryptophan residues may occur under acidic conditions. An increase in sorbitol concentration induced a blue shift. The fluorescence emission of IgY in a 50% sorbitol solution had a peak at 330 nm, which was the same emission peak that was exhibited by native IgY. Sorbitol could, therefore, be used as a good stabilizer of IgY under acidic conditions.

Egg yolk antibodies (IgY) and their applications in human and veterinary health: A review

“…However, the affinity of IgY to its antigen decreases with increasing temperature. Nonetheless, the addition of sucrose, maltose and glycine protects IgY from heat denaturation [8], while sorbitol stabilizes it at acid pH [26]. IgY is resistant to inactivation by the proteolytic enzymes trypsin and chymotrypsin, but is degraded by pepsin [27].…”

Anti-Helicobacter pylorieffects of IgY from egg york of immunized hens

“…In previous studies, in vivo H. pylori -eliminating capacity of IgY specific for urease or subunit of urease has been demonstrated [37,40-42]. However, since the titer of such antibodies tended to rapidly decrease at low pH, researches has focused on their efficacy in the stomach [40,43].…”

“…However, since the titer of such antibodies tended to rapidly decrease at low pH, researches has focused on their efficacy in the stomach [40,43]. Indeed, urease-specific IgY did not completely elliminated H. pylori from human patients, even though it markedly reduced expiratory urea concentration by alleviating gastritis and inhibiting urease activity [43,44].…”

Chapter 8 Control of intestinal diseases by dietary supplementation with antibodies

“…It enabled them to withstand acidic condition and to retain the antibody activity during the passage through the small intestine. Acid stability of IgY was enhanced in the presence of 30% sorbitol (Lee et al, 2002), or by encapsulation of IgY in the liposomes (Shimizu et al, 1993a).…”