Open AccessImmune responses of human T lymphocytes to novel hepatitis B virus-derived peptides
Author(s) -
Daisuke Yamamiya,
Eishiro Mizukoshi,
Kenzo Kaji,
Toshio Terashima,
Masaaki Kitahara,
Tatsuya Yamashita,
Kuniaki Arai,
Kazumi Fushimi,
Masao Honda
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0198264
Subject(s) - elispot , epitope , cytotoxic t cell , immune system , ctl* , hbsag , virology , hepatitis b virus , immunology , antigen , peptide vaccine , immunotherapy , biology , t cell , medicine , cd8 , virus , in vitro , biochemistry
Background & aims Many individuals are infected with hepatitis B virus (HBV) worldwide, and this virus is commonly controlled by treatments with interferon (IFN)-alpha and nucleoside analogues (NA). However, the complete elimination of HBV by these treatments is difficult and, thus, the development of new treatments is needed. Host immune responses are closely involved in the elimination of HBV, suggesting the usefulness of immunotherapy. In the present study, we attempted to identify novel cytotoxic T-lymphocyte (CTL) epitopes that are useful for immunotherapy against HBV. Methods CTL epitopes were predicted using computer software. Immune responses to each peptide were evaluated by IFN-γ ELISPOT and cytotoxic assays. The relationships between the immune responses to these newly identified CTL epitopes and the clinical backgrounds of patients and administration of NA were analyzed. Peptides were administered to mice as vaccines and peptide-specific T-cell induction was measured in vivo . Results Positive reactions to 10 synthesized peptides were detected in 3 or more patients using the IFN-γ ELISPOT assay, and concentration-dependent cytotoxicity against 2 of these peptides was observed in the cytotoxic assay. Some peptides that correlated with serum ALT, HBsAg, and HBV core-related antigen (HBcrAg) levels were identified. Immune reactions against some peptides were enhanced by the administration of NA. Regarding their effects as a vaccine, peptide-specific T-cells were induced by four peptides in vivo . Conclusions Novel HBV epitopes that correlated with HBsAg and HBcrAg levels were identified. These newly identified epitopes may be useful in the analysis of immune responses to HBV and development of immunotherapy against HBV.