CHARACTERIZATION OF POLLEN ANTIGENS FROM AMBROSIA L. (COMPOSITAE) AND RELATED TAXA BY IMMUNOELECTROPHORESIS AND RADIAL IMMUNODIFFUSION

The pollen antigens of various Ambrosia and related species were studied to learn whether substances closely related to antigen E (the major allergen of Ambrosia artemisiifolia) were present. After conventional immunoelectrophoresis, pollen extracts from six Ambrosia species each produced at least one pronounced precipitin line with antiserum for purified antigen E. Electrophoretic mobility was the same for several species (A. artemisiifolia, A. bidentata, A. psilostachya, and A. trifida) but was relatively lower for A. acanthicarpa and A. ambrosioides. Precipitin rings were also produced when pollen extracts of the various Ambrosia species were subjected to radial immunodiffusion in agarose which contained antiserum for purified antigen E. There was great variation among the Ambrosia species with respect to precipitin ring diameters. The variation may be due to differences among species in content of the antigen E-like substances or to altered interaction with the immobilized antibody. Crossed (2-dimensional) immunoelectrophoresis was shown to be useful for characterizing Ambrosia pollen antigens. Pollen extracts from A. artemisiifolia produced eight pronounced precipitin bands and at least eight faint, relatively fast-moving bands after crossed immunoelectrophoresis with antiserum against a whole pollen extract from the same species. One of the pronounced bands contained antigen E.