Production of a phage-displayed single chain variable fragment antibody against infectious bursal disease virus.

Purpose: To develop specific single chain variable fragments (scFv) against infectious bursal disease virus (IBDV) via phage display technology. Methods: Purified viruses were initially applied for iterative panning rounds of scFv phage display libraries. The binding ability of the selected scFv antibody fragments against the IBDV particles was analyzed by indirect enzyme-linked immunosorbent assay (ELISA) followed by blotting assays. Threedimensional (3D) structure of the selected scFv antibody fragment and VP3 protein were predicted through in silico analysis. Structural characterization of the antibody-antigen complexes was carried out by computational docking analysis. Results: The serological results obtained from the ELISA and blotting analysis showed that the selected clones produced specific scFv antibody fragments that were capable of effectively detecting infectious bursal disease (IBD) in the infected animal tissue. Biodiversity analysis by BstNI finger printing and nucleotide sequencing revealed that there was no major difference in nucleotide sequences of the selected clones. Further analysis demonstrated that this recombinant fragment of the antibody was able to bind to VP3 structural protein of IBDV with a molecular weight of ~30 kDa. Molecular docking results revealed that the binding energy of scFv to IBDV-VP3 was 545 kj/mol. Conclusion: The developed scFv antibody fragments possess great potentials for the diagnosis of IBD. The findings of the present study confirm the feasibility of using phage display technology for rapid production of antibodies against IBD diseases by applying naïve scFv libraries. [ABSTRACT FROM AUTHOR]