DIAGNOSTIC USE OF RECOMBINANT PROTEASE 3C AND RNA-POLYMERASE OF FOOT-AND-MOUTH-DISEASE VIRUS PRODUCED IN ESCHERICHIA-COLI

Recombinant plasmids containing foot-and-mouth disease virus A(22) pro tease (3c) and RNA polymerase (3d) gene fragments under the lac promot er were constructed and expressed in Escherichia coli. The 3C and 3D p roducts had the expected molecular weights of 24 and 43 kDa, respectiv ely. Procedures were developed for purification of virus-specific prot eins and ELISA for antibodies to viral nonstructural proteins in anima l sera. The sera from reconvalescent cattle and that immunized with di fferent vaccines from Russian biofactories were found to contain antib odies to 3C and 3D in varying titers. The use of purified nonstructura l proteins as antigens in ELISA permits diagnosis of foot-and-mouth di sease regardless of the virus type or subtype and without handling the intact virus, i.e., in full safety.