Further characterization of Ascaris suum component(s) with suppressive activity on the IgE antibody response

In order to characterize the component(s) of Ascaris suum responsible for damping of the IgE antibody production we demonstrated that the extract incubated in sodium acetate buffer, pH 4.5, maintained its suppressive effect and the same protein banding pattern by SDS-PAGE. Elimination of the lipoprotein components of the extract also left its damping properties unchanged. SDS-PAGE of the lipoprotein-free extract revealed practically the same pattern as shown by the whole extract, except for the high molecular weight polypeptides. These results indicate that the suppressive component(s) of A. suum did not precipitate and retained their activity at low pH. In addition, they appear not to be lipoproteins.