A systematic review of T-cell epitopes in hepatitis B virus: identification, genotypic variation and relevance to antiviral therapeutics.
BACKGROUND
The immune response to hepatitis B virus (HBV) is important for both viral control and disease pathogenesis. A detailed understanding of the HBV-specific T-cell responses may potentially lead to novel therapeutic strategies for HBV.


METHODS
All English language journal articles (including articles in press) up to October 2007 were retrieved using searches of MEDLINE, EMBASE and the Cochrane Controlled Trial Registry. An extensive database of HBV sequences (SeqHepB) and GenBank were used to assess the degree of sequence variation in each epitope. The new standardized nomenclature for HBV amino acid position number was applied to all previously defined epitopes.


RESULTS
Forty-four HBV-specific human leukocyte antigen (HLA) class I restricted and 32 HBV-specific HLA class II restricted epitopes have been defined and have been identified in all HBV genes. The majority of HLA class I restricted epitopes have been defined in HLA-A2-positive individuals in the setting of acute HBV infection. There is significant sequence variation of these epitopes within and between HBV genotypes. Newer HBV immunotherapeutics appear promising but are still in early phases of development.


CONCLUSIONS
Identification of HBV-specific epitopes in non-HLA-A2-positive individuals and recognition of genotypic variation across epitopes are important for the future development of novel immunotherapeutic strategies for the management of chronic HBV infection.
Desmond
Christopher P
CP
Department of Gastroenterology, Alfred Hospital, Melbourne, Australia.
Bartholomeusz
Angeline
A
Gaudieri
Silvana
S
Revill
Peter A
PA
Lewin
Sharon R
SR
D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000627:therapeutic use*; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D014644:Genetic Variation; D005838:Genotype; D006680:HLA Antigens / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D006515:Hepatitis B virus / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D008969:Molecular Sequence Data
D000998:Antiviral Agents; D018984:Epitopes, T-Lymphocyte; D006680:HLA Antigens