Production and application of recombinant haemagglutinin neuraminidase of Newcastle disease virus

Abstract

Objective To discuss the possibility of expressing the haemagglutinin-neuraminidase (HN) protein in prokaryotic system such as Escherichia coli (E. coli) cells by cloning the full length HN gene. Methods The full length HN gene of Newcastle Disease Virus (NDV) of size 1 734 bp was preciously isolated by RT-PCR. The sequence was assessed and submitted to Nucleic Acid Databank (NCBI) and the gene ID was EU215390.1 after cloning and sequencing. Now the assessed HN gene was subcloned into pET 32 a+ expression vector for production the HN protein in E. coli, BL21 (DE3) P LYSS cells following standard protocols. The crude lysate protein from the induced positive clone was size assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and their haemagglutination (HA) property against chicken RBC was assessed by standard micro HA test. Results The molecular size of the full HN gene of NDV as assessed by cloning and digesting the positive clone to release the insert was 1.7 kb. The expressed protein in both crude and pure form was assessed to be 63 kDa and 81 kDa, respectively. The HA activity of the crude protein of the positive clone was 1 in 40. Conclusions This finding indicates that the fusion protein retains the biological activity of native protein in the crude form and therefore could be used as a diagnostic reagent for antibody detection and for routine assessment of immune status in commercial layer forms.