Production of a fragment of glycoprotein G of herpes simplex virus type 2 and evaluation of its diagnostic potential

Abstract

INTRODUCTIONHerpes simplex virus type 2 (HSV-2) is the most common cause of genital herpes. Glycoprotein G (gG) is a prototype antigen for type-specific serodiagnosis distinguishing between HSV type 1 (HSV-1) and HSV-2 infections. As immunological diagnosis kits for accurate differentiation between HSV-1 and HSV-2 antibodies can be expensive, there is a need to develop a convenient, sensitive, specific and cost-effective serodiagnostic kit. METHODSWe successfully expressed a fragment of gG comprising residues 321-580 of HSV-2 with histidine tag (gG 321-580His ) in a Bac-to-Bac baculovirus expression system, which had an antigenicity similar to its native counterpart. An indirect enzyme-linked immunosorbent assay (ELISA) was developed using gG 321-580His as the diagnostic antigen and evaluated by comparison with a commercial HerpeSelect 2 ELISA immunoglobulin G kit as reference. RESULTSIn testing 318 field serum samples, the diagnostic relative sensitivity and specificity of the developed gG 321-580His -ELISA test in qualitative comparison with the commercial kit were 93.81% and 96.74%, respectively, and the accuracy was 94.65%. CONCLUSIONThe study indicates that gG 321-580His has a high diagnostic potential for HSV-2 virus serodiagnosis in humans. Keywords: baculovirus expression system, glycoprotein G, herpes simplex virus type 2, immunodominant fragment, indirect enzyme-linked immunosorbent assay