Selection and characterization of single-chain recombinant antibodies against infectious haematopoietic necrosis virus from mouse phage display library

Six single-chain fragment variable (scFv) antibodies against infectious haematopoietic necrosis virus (IHNV) were selected from an antibody phage display library by phage display technology. The soluble scFv antibodies showed a molecular weight 32 kDa by Western blot. Dot blot analysis revealed that the six scFv antibodies could recognize IHNV. For enzyme linked immunosorbent assay (ELISA), four scFv antibodies (P1A4, P1A12, P1D5 and P3E2) showed cross-reactivity with spring viraemia of carp virus (SVCV). However, none of the six scFv antibodies had cross-reaction with Pike fry rhabdovirus (PFRV), Soft-shelled turtle iridovirus (STIV), viral haemorrhagic septicemia virus (VHSV), or viral nervous necrosis virus (VNNV). Indirect immunofluorescence results showed that all of these scFv antibodies reacted positively with virus in the IHNV-infected cells. These scFv antibodies will be useful in diagnostic test development and pathogenesis studies for IHNV.