Novel Identified HLA-A*0201-Restricted Hantaan Virus Glycoprotein Cytotoxic T-Cell Epitopes Could Effectively Induce Protective Responses in HLA-A2.1/Kb Transgenic Mice May Associate with the Severity of Hemorrhagic Fever with Renal Syndrome

Abstract

Hantaan virus (HTNV) infections can cause severe hemorrhagic fever with renal syndrome (HFRS) in humans, which is associated with high fatality rates. Cytotoxic T cell (CTL) responses contribute to virus elimination; however, to date, HLA class I allele-restricted HTNV glycoprotein (GP) epitopes recognized by CTLs have not been reported, limiting our understanding of CTL responses against HTNV infection in humans. In this study, 34 HTNV GP nine-mer epitopes that may bind to HLA-A*0201 molecules were predicted using the BIMAS and SYFPEITHI database. Seven of the epitopes were demonstrated to bind to HLA-A*0201 molecules with high affinity via the T2 cell binding assay and were successfully used to synthesize peptide/HLA-A*0201 tetramers. The results of tetramer staining showed that the frequencies of each epitope-specific CTL were higher in patients with milder HFRS, which indicated that the epitopes may induce protective CTL responses after HTNV infection. IFN-γ-enzyme-linked immunospot analysis further confirmed the immunoreactivity of epitopes by eliciting epitope-specific IFN-γ-producing CTL responses. In an HTNV challenge trial, significant inhibition of HTNV replication characterized by lower levels of antigens and RNA loads was observed in major target organs (liver, spleen, and kidneys) of HLA-A2.1/Kb transgenic mice pre-vaccinated with nonapeptides VV9 (aa8–aa16, VMASLVWPV), SL9 (aa996–aa1004, SLTECPTFL) and LL9 (aa358–aa366, LIWTGMIDL). Importantly, LL9 exhibited the best ability to induce protective CTL responses and showed a prominent effect on the kidneys, potentially preventing kidney injury after HTNV infection. Taken together, our results highlight that HTNV GP-derived HLA-A*0201-restricted epitopes could elicit protective CTL responses against the virus, and that epitope LL9 functions as an immunodominant protective epitope that may advance the design of safe and effective CTL-based HTNV peptide vaccines for humans.

Genetic diversity and evolution of Hantaan virus in China and its neighbors

“…This might be a clue to the possibility of immune escape in these regions. We found an epitope (ID 742143) located on signal peptide, which showed high binding affinity to HLA-A � 0201 molecules and frequencies of epitope-specific cytotoxic T lymphocytes in the peripheral blood mononuclear cells of patients with HFRS and could induce CD8+ T-cell responses to inhibit HTNV replication [41]. Experimentation is needed to determine whether peptides containing these residues can confer escape or can be used to develop serotype-specific reagents for serology-based diagnostics.…”

Development of tumour peptide vaccines: From universalization to personalization

“…Dettling et al analysed the T cell target antigen spectrum of glioma patients by IFN‐γ ELISpot and then identified the HLA‐A*02–restricted T cell epitope of the neoantigen by mass spectrometry and pMHC‐I tetramer staining . Finally, Tang et al used IFN‐γ ELISpot to induce epitope‐specific CTL responses to determine epitope immunoreactivity in peripheral blood mononuclear cells, confirming seven epitopes bound to high‐affinity HLA‐A*0201 molecules, and successfully synthesized the peptide‐HLA‐A* 0201 tetramer …”

Protective CD8+ T-cell response against Hantaan virus infection induced by immunization with designed linear multi-epitope peptides in HLA-A2.1/Kb transgenic mice

“…Immunization of HTNV linear multi-epitope peptide inhibited HTNV replication in HLA-A2.1/K b Tg mice after HTNV challenge Next, the HTNV challenge experiments were conducted to determine whether HTNV linear multi-epitope peptide immunization could defend against HTNV infection in vivo. A model of HTNV infection and replication in HLA-A2.1/K b Tg mice was established from a previous study [20,23]. Consistent with the previous detection, few detectable HTNV RNA could be observed in the lungs, cerebrum and heart in all Tg mice groups after HTNV challenge, whereas high levels of HTNV RNA loads were displayed in the liver, spleen and kidney in each Tg mouse from the negative control group injected with PBS, suggesting that the liver, spleen and kidney are the major organs for HTNV infection and replication in Tg mice.…”