Purification and characterization of a factor which inhibits retrovirus replication

Chick embryo cells (CEC) secrete a factor which inhibits HIV1 replication. Non-productive infection of CEC with vesicular stomatitis virus increases 5-10-fold the synthesis of this factor. After purification by FPLC the biological activity is associated with a heat-resistant protein of approximately 150 kDa, composed of two subunits of 70 and 58 kDa and charged negatively. Monoclonal antibodies raised against this protein block the inhibitory activity of the purified protein and react with the 150-kDa and 58-kDa proteins in Western blots.