Leukocyte inhibiting factor (LIF) production from human lymphocytes stimulated by bacterial lipopolysaccharides

Leukocyte inhibiting factor (LIF) release from lymphocytes cultures stimulated by bacterial lipopolysaccharides (LPS) has been investigated. Human lymphocytes cultured in the presence of E, coli or S. enteritidis LPS were able to release in the supernatants a substance with the following properties: a) same elution pattern of Bovine Serum Albumin (MW 69000) when filtered on Sephadex G-100; b) it migrates on disc electrophoresis a an albumin; c) not dialyzable; d) not cytotoxic; e) inhibition of polymorphonuclear cells migration in agarose plates; f) heat stability at 56 degrees C for 30'. This substance could be likely identified as LIF.