Enterobacterial common antigen-tetanus toxoid conjugate as immunogen.

The methods of limited periodate oxidation and reductive amination were used to obtain covalently linked enterobacterial common antigen (ECA) with tetanus toxoid. This procedure is simple and gives a good yield of the conjugate with high ECA content (molecular ratio of ECA to tetanus toxoid, 6:1). The ECA-tetanus toxoid conjugate is immunogenic in rabbits, in contrast to free ECA or a mixture of ECA with proteins. This conjugate produces high levels of ECA-specific immunoglobulin G antibodies, which can be used as a standard serum.