Evaluation on Protective Effects of Sucralfate on Anti-H.pylori HpaA IgY in Vitro

Objective To evaluate the protective effects of sucralfate on anti-H.pylori HpaA immunoglobulin yolk(HpaA IgY) and provide experimental basis for preparation of IgY by oral administration.Method The recombinant protein HpaA was expressed in engineering bacteria DH5α-HpaA-pQE30 and purified.HpaA IgY was prepared by inoculating purified HpaA in Lohman hen and then depurated.Sucralfate of different concentration was added into HpaA IgY under different pH(1.0-3.0) and contained different concentration of pepsin,and was enforced with freeze thawing.The residuary antibody activity(AR/AC%)of IgY was determined by the method of ELISA.Results The activity of HpaA IgY containing 60% sucralfate could keep its activity at 65.8% under pH 1.5.The activity of IgY containing 30% sucralfate could keep its activity at 85.4% while 50% sucralfate could completely keep its activity under pH 2.0.Under pH 3.0,30% sucralfate could remain its activity at 87.3% while sucralfate above 40% completely protected its activity.As the concentration of pepsin was 0.02mg/mL,the residuary antibody activity of IgY containing 10%,30%,50% sucralfate were 62.8%,71.6%,82.5% under Ph 2.0 and 75.6%,87.4%,94.5% under pH 3.0.After enforced with freeze thawing 10%,30%,50% sucralfate may make the residuary antibody activity of IgY increase to 70.6%,82.7% and 89.3%.Conclusion HpaA IgY containing 30% or above sucralfate can improve the tolerance of IgY against low pH,pepsin and freeze thawing intervention.It shows that sucralfate is a satisfactory protectant for HpaA IgY.