Demonstration of human reagin in monkey tissues. V. In vitro passive sensitization of monkey ileum with absorbed globulin fractions from sera of patients sensitive to ragweed

In the previous studies it was shown that the following serum fractions of ragweed-sensitive patients are able to sensitize the monkey ileum when examined by the Schultz-Dale (S-D) test: euglobulin (IgM), zinc precipitate at 22° C. (IgG), and zinc supernatant (IgA). In the reported studies, these fractions were examined by the S-D test after the immunoglobulin contents were absorbed. The euglobulin (IgM) and zinc precipitate (IgG) fractions were negative after absorption, but the zinc supernatant (IgA) fraction not only remained positive but the tissue-sensitizing ability increased. This activity could be due to the IgE globulin which may be present in the zinc supernatant fractions, as shown by Ishizaka. Also, chromatographed serum fractions containing IgE, IgG, and IgA antibodies to ragweed extract (Antigen E) were examined by the S-D and Prausnitz-Küstner tests. Only such fractions which contained IgE antibody were positive in both tests. The absorption of these positive fractions with rabbit monospecific antisera to human IgA or IgG did not influence the reaginic activity, while the antisera to IgE globulin eliminated the activity completely.