MODIFICATION OF HOST RESPONSES TO BACTERIAL ENDOTOXINS. II. PASSIVE TRANSFER OF IMMUNIY TO BACTERIAL ENDOTOXIN WITH FRACTIONS CONTAINING 19S ANTIBODIES

Abstract

Serum from rabbits rendered tolerant or immune to 100 MPD-3/kg of endotoxin when passively transferred to normal rabbits gave partial tolerance to the standard dose of endotoxin. The same serum was fractionated by DEAE chromatography into 4 major fractions. Immunoelectrophoretic analysis indicated that the 7S gamma(2)-and the 19S gamma(1)-immunoglobulins were separated into two distinct fractions. Of the four fractions tested, only fraction IV containing 19S gamma(1)-immunoglobulm conferred complete pyrogenic tolerance to 100 MPD-3/kg of endotoxin. Additional fractionation of DEAE fraction IV by exclusion chromatography on sephadex G-200 gave 3 fractions. Of these only the first, containing 19S gamma(1)-immunoglobulin conferred complete pyrogenic and lethal tolerance to normal rabbits. There was no correlation between the quantity of O-specific antibodies and the ability to transfer tolerance. It is concluded that endotoxin tolerance involves a classical immune mechanism which includes both 19S gamma(1)-immunoglobulin specific for toxophore groups common to many endotoxins and a normally functioning RES. To avoid confusion with immunologic tolerance, it is suggested that the term endotoxin immunity be substituted for endotoxin tolerance.