Clinical and serologic study of the relationship of giant (ambrosia trifida) and low (ambrosia artemisiaefolia) ragweed pollen

Abstract

1. 1. Extracts of different lots of giant ragweed pollen, irrespective of year or source, when diluted on the protein nitrogen unit were alike as far as direct skin tests or their capacity to produce constitutional reactions could determine. 2. 2. Extracts of different lots of low ragweed pollen, irrespective of year or source, when diluted on the protein nitrogen unit were alike as far as direct skin tests or their capacity to produce constitutional reactions could determine. 3. 3. Direct intradermal skin tests on ragweed sensitive individuals failed to show determinable differences between the giant and the low ragweed. 4. 4. Low ragweed extracts had a greater capacity to produce constitutional reactions than giant ragweed extracts. 5. 5. Passive transfer sites made with sensitive serum dilutions when tested with giant and low ragweed extracts and their proteins showed slightly greater reactions to the low ragweed. 6. 6. The serum neutralizing capacity of low ragweed extracts and protein was from three to ten times stronger than similar giant ragweed preparations. 7. 7. When a pure species of ragweed pollen was used, the resulting extracts were of equivalent serum neutralizing capacity when standardized on the protein nitrogen unit. 8. 8. Ragweed sensitive serums mixed with ragweed extracts and injected into non-sensitive skin produced an immediate specific reaction.