DIPHTHERIA ANTITOXIN: ANTIGEN-COMBINING AND TOXIN-NEUTRALIZING PROPERTIES OF PAPAIN FRAGMENTS.

Papain-digested rabbit antibodies to diphtheria toxoid were separated into three fragments. Fragments I and II combined with toxoid in vitro and neutralized toxin. The ratios of these activities were not the same for fragments I and II, indicating that antitoxic and accessory antibody may be distributed unequally between two classes of antibody.

ISOLATION OF AN ANTIHISTAMINIC PRINCIPLE RESEMBLING TOMATINE FROM CROWN GALL TUMORS.

Antihistaminic activity was demonstrated previously in extracts of crown gall tumors by assaying in vivo. A crystalline substance isolated from the crude extracts has now been found to possess a high degree of potency against histamine, acetylcholine, bradykinin, and serotonin when assayed in vitro. The chemical characteristics of the substance resemble closely those of tomatine.

AN ANTIHISTAMINE-LIKE SUBSTANCE (OR SUBSTANCES) IN EXTRACTS PREPARED FROM HUMAN TISSUES.

A method for the extraction of an antihistamine-like substance (or substances) from human tissues is described. The method has demonstrated the presence of this active principle(s) in a large variety of human tissues, so far without exception. The substance(s) has a wide range of activity in antagonizing the in vitro effects of histamine, 5-hydroxytryptamine and bradykinin and the Schultz-Dale reaction on the guinea-pig ileum and rat uterus preparations.