Expression of 1B capsid protein of Foot- and-mouth disease virus (FMDV) using baculovirus expression system and its validation in detecting SAT 2-specific antisera

Foot-and-mouth disease virus (FMDV) is one of the most devastating animal viruses that affect livestock worldwide. The 1B capsid of FMDV has been widely used to detect and confirm the infection. In the present study, the sequence coding for 1B subunit of FMDV capsid was expressed in insect cells using the baculovirus expression system under the polyhedrin (polh) promoter. The expression of 1B capsid protein was validated in the culture filtrate of insect cells using SDS-PAGE and western blotting. The culture filtrate containing recombinant 1B capsid (r1B) was used as a coated antigen in an indirect enzyme-linked immunosorbent assay (ELISA). The antigenicity and specificity of r1B against SAT 2 serotype-specific antibodies were assessed. Our results revealed that a protein concentration as low as 25 ng could detect SAT 2-specific antibodies in ELISA. The results highlight the application of insect cells developed r1B protein in the detection of FMDV. Further studies are required to determine the ability of r1B to detect other FMDV serotypes.