OBJECTIVETo screen and identify dengue virus type 2 specific antigens and establish an enzyme-linked immunosorbent assay (ELISA) for detecting dengue virus type 2 antibody.

METHODSUsing the bioinformatic software DNAstar and ANTHEPROT, we analyzed the hydrophilicity, flexibility, surface probability and antigenicity of dengue virus type 1-4, Japanese encephalitis virus, and Yellow fever virus M and E protein amino acid sequences, and also evaluated the influence of secondary structure. The specific epitopes of dengue virus type 2 were predicted according to the epitope location and amino acid sequence similarity, and the epitope conservation was assessed using the sequence information of different dengue virus type 2 strains in GenBank. Based on the results of bioinformatic analysis, 5 specific epitopes were amplified and inserted into the prokaryotic expression vector pET32a, which were transferred into E. coli Rosetta (DE3) for expression of the proteins. SDS-PAGE and Western blotting were used to identify the expressed proteins and test their antigenicities. The antigen selected by Western blotting was used to establish the ELISA system for dengue virus type 2 antibody detection.

RESULTSBioinformatic analysis predicted 8 possible dengue virus type 2 specific epitopes, and 6 of them were efficiently expressed in E. coli. Western blotting confirmed 1 dengue virus type 2 specific antigen, the ELISA system for dengue virus antibody detection was successfully established using this specific antigen.

CONCLUSIONWe have obtained a dengue virus type 2 specific antigen and established an ELISA system for detection of dengue virus type 2 antibody.