Development and use of a biotinylated 3ABC recombinant protein in a solid-phase competitive ELISA for the detection of antibodies against foot-and-mouth disease virus.

A biotinylated 3ABC recombinant protein was developed and used in a competitive ELISA (cELISA) to detect foot-and-mouth disease virus (FMDV) antibodies in cattle, sheep and pigs. In this report, we describe the cloning and expression of 3ABC protein in Escherichia coli cells as fusion protein with 6xHis and biotin. This cELISA uses streptavidin to capture bacterially expressed and in vivo biotinylated 3ABC antigen. The antigen capture strategy provides a simple and reliable method, which does not require purification of recombinant antigen before the serological assay. An hyperimmune guinea pig antiserum produced against purified 6xHis-3ABC was used as competitor in the test. The potential use of this cELISA for the identification of antibodies induced by FMD virus infection from those induced by vaccination is discussed.