Studies with antigens: III. The preparation of purified house dust extract

Abstract

The processes of purification of house dust extract described resulted in the removal of a large proportion of allergically inert materials. The purified and concentrated extract obtained by fractionation and refractionation of house dust extract with various organic solvents was further purified by dialysis through No. 1200 cellophane. Extracts purified by fractional precipitation and by fractionation and dialysis contained a significantly greater degree of skin reacting activity per unit weight of dissolved solids than did the original extracts from which they were processed. Since the activity was significantly greater per unit weight of dissolved solids, it was evident that the increased activity of the purified extracts was due to an increased concentration of the allergic factor. Precipitation of extracts purified by water-miscible organic liquids, with ammonium sulfate and other sulfate salts in high concentrations, produced further purification. This was significantly greater than that produced by treatment of the original extract with ammonium sulfate or by its extensive dialysis through a suitable semipermeable membrane. Treatment of original house dust extracts or dialyzed original house dust extracts with water-miscible organic liquids removed nonspecific materials which were otherwise precipitated from these extracts by ammonium sulfate. Treatment of aqueous extracts of house dust by fractionation with water-miscible organic liquids, and then treatment with ammonium sulfate or other sulfate salts in high concentrations, followed by dialysis, produced a highly purified house dust extract.