Antigens of Ambrosia elatior (short ragweed) pollen. I. Crossed immunoelectrophoretic analyses.

A crude extract of short ragweed pollen was obtained by extraction, centrifugation, dialysis and freeze-drying. Crossed immunoelectrophoresis, with a high-titer purified rabbit antibody fraction, revealed that the extract contained at least 52 antigens, of which 33 migrated toward the anode, 16 toward the cathode, and 3 toward both the anode and cathode. The electrophoretic precipitation pattern indicated a great deal of electrophoretic heterogeneity in several of the antigens. The overall distribution of apparent m.w. for 35 of the 52 antigens and the approximate m.w. for 19 identified antigens were determined by a combination of gel filtration and immunochemical analysis. Among antigens with m.w. weights less than or equal to 10,000, 8 of 10 were basic; on the other hand, all 5 identified antigens with m.w. above 40,000 were acidic. The apparent pI distribution for 30 antigens, and more precise pI values for 20 of 52 antigens, were determined by means of sucrose-gradient isoelectric focusing. The data obtained provide a reproducible reference system of considerable use in ragweed allergen chemistry and enable one to predict conditions for isolation of ragweed antigens.