Expression and characterization of immunodominant region of fusion protein of peste des petits ruminants virus in E. coli

Abstract

The present study envisages expression of immunodominant ectodomain of peste des petits ruminants virus (PPRV) fusion (F) protein in Escherichia coli BL21 (DE3) and its characterization to assess its immunoreactivity. The ectodomain gene sequences corresponding to 222 amino acids, was amplified from PPR vaccine virus, cloned into pET33b vector and expressed in E. coli at an optimal temperature of 37 ◦C with 1 mM IPTG for 5 h. The expressed and Ni-NTA purified PPRV F protein (31 kDa) was characterized by SDS-PAGE and Western blot using anti-his-tagged-conjugate, anti-serum raised against recombinant PPRV F protein, hyper immune serum against whole PPRV and convalescent sera from sheep and goats. The expressed protein was assessed for its immunoreactivity by ELISA and immunoblotting. The antibody response mounted against the recombinant PPRV F protein in immunized rabbits was detected by recombinant PPRV F antigen based indirect ELISA, and whole virus antigen based indirect ELISA, which indicating the native confirmation ofthe expressed protein in E. coli. Indirect ELISA was optimized using known true positive and negative sera with respect to PPRV antibodies in order to assess the reactivity of the PPRV F protein in detecting PPRV F antibodies in small ruminants. The E. coli expressed recombinant ectodomain of PPRV F protein exhibits immunoreactivity and was able to specifically detect PPRV antibodies in response to both vaccination and disease in natural host.