Identification of an interleukin‐1 beta binding protein in human plasma

Abstract
A covalent cross‐linking technique was used to bind iodinated interleukin‐1 (IL1) alpha and beta to plasma proteins. One specific IL1 beta binding protein was observed, that when cross‐linked to 125I‐ILl beta migrated to approximately 60 kDa on SDS‐PAGE. The protein did not bind IL1 alpha. The 43 ‐kDa protein was partially purified using a wheat germ agglutinin affinity column. The isolated factor again specifically bound IL1 beta, and appeared to consist of single chain glycoprotein. The protein was heat stable and had a rapid association time with IL1 beta. This protein may be an important carrier molecule for IL1 beta in vivo.