Allergic and Immunologic Studies of a “Purified” Fraction of Ragweed Pollen

Summary and Conclusions

1. 1. The allergenic and antigenic properties of pool C, a “purified” fraction of ragweed pollen, were investigated. As compared to whole ragweed pollen extract, pool C was found to be highly antigenic as measured by its ability to stimulate antibody production in rabbits, induce passive cutaneous anaphylaxis and provide indirect hemagglutination with both human and animal antisera.

2. 2. Pool C is not immunochemically pure as evidenced by three or four lines produced by its homologous antisera in immunoelectrophoresis. However, many of the antigens in the whole ragweed extract have been eliminated.

3. 3. Positive hemagglutination titers with pool C were found with the sera of 72% of untreated ragweed-sensitive individuals. This contrasted greatly with 20% positive reactions found with whole ragweed extract.

4. 4. On a weight basis, pool C was 100 to 1000 times more skin-reactive than whole ragweed extract, both by direct and passive transfer tests.

5. 5. In vitro and particularly in vivo neutralization tests indicated that some of the allergens in whole ragweed extract have been eliminated in the preparation of pool C.