[Identification of a novel antigenic epitope on GST fusion-expressed and ORF2-encoded proteins of hepatitis E virus].
OBJECTIVE
To investigate the effect of a GST tag on the antigenic structure of GST fusion-expressed and ORF2-encoded recombinant proteins of hepatitis E virus (HEV).


METHODS
The monoclonal antibodies (mAb) were prepared with a GST fusion protein, p166Chn-GST, which was derived from a Chinese HEV strain. Then they were tested by indirect ELISA, competition ELISA and Western blot with different GST fusion, His fusion or non-fusion recombinant proteins derived from HEV reference strains of all 4 genotypes and other non-HEV recombinant proteins.


RESULTS
Three mAb named 1A8, 9B4 and 8H10 were obtained. All of them reacted to p166Chn-GST but did not react to GST. mAb 1A8 and 9B4 reacted to 4 p166-GST proteins of different HEV genotypes and 2 N- or C-terminal truncated p166Chn-GST proteins named p146Chn-GST and p137Chn-GST, but they did not react to 4 p166-His proteins of different HEV genotypes and a non-fusion p179Chn protein. No detectable signals were found when 1A8 and 9B4 were subjected to HEV antigen competition ELISA or Western blot after SDS-PAGE. No cross reaction was observed between the two mAb and HEV-irrelevant GST fusion proteins, either.


CONCLUSIONS
A novel antigenic epitope recognized by mAb 1A8 and 9B4 appears on the GST fusion-expressed and ORF2-encoded HEV recombinant proteins and it is dependent on the conformational folding of both GST and HEV sequences.
Liang
Jiu-hong
JH
Department of Microbiology and Immunology, School of Medicine, Southeast University, Nanjing 210009, China.
Liang
Li-min
LM
Dong
Min
M
Han
Zhen-ge
ZG
Dong
Chen
C
Meng
Ji-hong
JH
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology*; D005260:Female; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics*; D016752:Hepatitis E virus / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D000956:Antigens, Viral; D000939:Epitopes; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D005982:Glutathione Transferase