Identification of a novel conserved HLA-A*0201-restricted epitope from the spike protein of SARS-CoV.
BACKGROUND
The spike (S) protein is a major structural glycoprotein of coronavirus (CoV), the causal agent of severe acute respiratory syndrome (SARS). The S protein is a potent target for SARS-specific cell-mediated immune responses. However, the mechanism CoV pathogenesis in SARS and the role of special CTLs in virus clearance are still largely uncharacterized. Here, we describe a study that leads to the identification of a novel HLA-A*0201-restricted epitope from conserved regions of S protein.


RESULTS
First, different SARS-CoV sequences were analyzed to predict eight candidate peptides from conserved regions of the S protein based upon HLA-A*0201 binding and proteosomal cleavage. Four of eight candidate peptides were tested by HLA-A*0201 binding assays. Among the four candidate peptides, Sp8 (S958-966, VLNDILSRL) induced specific CTLs both ex vivo in PBLs of healthy HLA-A2+ donors and in HLA-A2.1/Kb transgenic mice immunized with a plasmid encoding full-length S protein. The immunized mice released IFN-gamma and lysed target cells upon stimulation with Sp8 peptide-pulsed autologous dendritic cells in comparison to other candidates.


CONCLUSIONS
These results suggest that Sp8 is a naturally processed epitope. We propose that Sp8 epitope should help in the characterization of mechanisms of virus control and immunopathology in SARS-CoV infection.
Lv
Yanbo
Y
Institute of Immunology, PLA, Third Military Medical University, 30 Gaotanyan Street, Chongqing 400038, PR China. boyl@sina.com.cn
Ruan
Zhihua
Z
Wang
Li
L
Ni
Bing
B
Wu
Yuzhang
Y
D000818:Animals; D002460:Cell Line; D017124:Conserved Sequence; D017934:Coronavirus / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015234:HLA-A Antigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015789:HLA-A2 Antigen; D006801:Humans; D007114:Immunization; D007371:Interferon-gamma / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding; D045169:Severe Acute Respiratory Syndrome / Q000276:immunology; D064370:Spike Glycoprotein, Coronavirus; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
D018984:Epitopes, T-Lymphocyte; D015234:HLA-A Antigens; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus; D007371:Interferon-gamma