Establishment of method for seroepidermiological detection of human herpes virus 8 infection by using the fusion protein in the prokaryotic expression system as antigen for testing

To establish a sensitive and specific method for seroepidermiological detection of human her- pes virus 8(HHV-8)infection,three potent antigenic proteins encoded by open reading frames(ORFs) K8.1,65 and 73C in genome of HHV-8 were produced as glutathione S-transferase fusion protein in the prokaryotic expression system and was used as antigen for testing.The recombinant fusion protein ex- pressed in the prokaryotic expression vector E.coli BL21 was purified by glutathione Sepharose 4B affin- ity chromatography and was quantitated with SDS-PAGE.All these 3 fusion proteins produced in the pro- karyotic expression system showed good immunogenicity as demonstrated by Western blotting and could be recognized by mixed sera of patients with Kaposi′s sarcoma(KS).The immuno-reactivities of the single or compound fusion protein were determined by means of ELISA and compared with the traditional immu- nofluorescence assay(IFA)to determine their sensitivity and specificity of the test.It was demonstrated that the sensitivity of mixed-antigen ELISA method was significantly higher than that of IFA(81.8% vs 34.4%),while the specificity of the former was demonstrated to be 97.9%.The coincidence of the de- tection rate between these two methods was considerably high,approaching up to 90.0%.These results suggest that the mixed antigen ELISA assay appears to be a sensitive and specific method for sero-epide- miological detection of human herpesvirus 8 infection.