Identification of immunodominant Helicobacter pylori proteins with reactivity to H. pylori-specific egg-yolk immunoglobulin.

The importance of hens eggs as a source of specific antibodies (IgY) is well recognized. The protective effect of IgY obtained from hens immunized with Helicobacter pylori whole-cell lysate has been reported for the control of H. pylori infection. However, IgY produced by whole-cell lysates presents the possibility of cross-reactivity with other bacteria, including the normal human flora, and this could decrease the efficiency of IgY. In the present study, the immunodominant proteins of H. pylori with reactivity to H. pylori-specific IgY (IgY-Hp) were identified. IgY obtained from hens immunized with various fractions of H. pylori proteins was isolated and purified, titres of IgY-Hp against H. pylori were determined and cross-reactivity between IgY-Hp and normal human bacteria was examined by Western blot analysis. Finally, immunodominant H. pylori proteins were identified by LC/MS analysis. IgY obtained 2 months after immunization with H. pylori whole-cell lysate showed the highest antibody titre. Five immunodominant proteins were identified that were strongly reactive to IgY-Hp: urease beta-subunit (62 kDa), heat-shock protein 60 (60 kDa), urease alpha-subunit (26 kDa), probable peroxiredoxin (22 kDa) and probable thiol peroxidase (18 kDa). Immunization of hens with the immunodominant proteins identified would produce a more specific IgY against H. pylori.

Use of egg yolk-derived immunoglobulin as an alternative to antibiotic treatment for control of Helicobacter pylori infection.

The present study evaluated the potential use of immunoglobulin prepared from the egg yolk of hens immunized with Helicobacter pylori (immunoglobulin Y [IgY]-Hp) in the treatment of H. pylori infections. The purity of our purified IgY-Hp was 91.3%, with a yield of 9.4 mg of IgY per ml of egg yolk. The titer for IgY-Hp was 16 times higher than that for IgY in egg yolk from nonimmunized hens, and IgY-Hp significantly inhibited the growth and urease activity of H. pylori in vitro. Bacterial adhesion on AGS cells was definitely reduced by preincubation of both H. pylori (10(8) CFU/ml) and 10 mg of IgY-Hp/ml. In Mongolian gerbil models, IgY-Hp decreased H. pylori-induced gastric mucosal injury as determined by the degree of lymphocyte and neutrophil infiltration. Therefore, in this experimental model, H. pylori-associated gastritis could be successfully treated by orally administered IgY-Hp. The immunological activity of IgY-Hp stayed active at 60 degrees C for 10 min, suggesting that pasteurization can be applied to sterilize the product. Fortification of food products with this immunoglobulin would significantly decrease the H. pylori infection. In conclusion, the IgY-Hp obtained from hens immunized by H. pylori could provide a novel alternative approach to treatment of H. pylori infection.