Fully "recombinant enzyme-linked immunosorbent assays" using genetically engineered single-chain antibody fusion proteins for detection of Citrus tristeza virus

Recombinant single-chain variable fragment antibodies (scFv) that bind spec ifically to Citrus tristeza virus (CTV), which cause the most detrimental v iral disease in the citrus industry worldwide, were obtained from the hybri doma cell lines 3DF1 and 3CA5. These scFv were genetically fused with dimer ization domains as well as with alkaline phosphatase, respectively, and dia gnostic reagents were produced by expressing these fusion proteins in bacte rial cultures. The engineered antibodies were successfully used for CTV dia gnosis in plants by tissue print enzyme-linked immunosorbent assay (ELISA) and double antibody sandwich-ELISA. The fully recombinant ELISAs were as sp ecific and sensitive as conventional ELISAs performed with the parental mon oclonal and bodies, showing the usefulness of recombinant antibodies for ro utine detection of a virus in woody plants for the first time.