Carbonyl Iron: A New Adjuvant for Experimental Autoimmune Diseases

Abstract

Carbonyl iron, a form of metallic iron characterized by spherical particles, was a potent adjuvant for production of allergic encephalomyelitis in rats. It was injected intraperitoneally as a saline suspension mixed with an aqueous homogenate of whole neural tissue. Adjuvant activity was also found in kaolin suspensions but not in other forms of metallic iron, iron oxides, iron dextran, or a number of other particulate materials. Carbonyl iron was effective when administered 1 day before or after the antigen but not when given by a different route. Cell suspensions from lymph nodes draining the site of inoculation were capable of transferring the disease passively to unimmunized recipients. The ease of detecting iron and its magnetic qualities should make carbonyl iron a useful material for investigation of adjuvant mechanisms and of cellular immunology.