Acute resolving woodchuck hepatitis virus (WHV) infection is associated with a strong cytotoxic T-lymphocyte response to a single WHV core peptide.
Woodchucks infected with woodchuck hepatitis virus (WHV) are an excellent model for studying acute, self-limited and chronic hepadnaviral infections. Defects in the immunological response leading to chronicity are still unknown. Specific T-helper cell responses to WHV core and surface antigens (WHcAg and WHsAg, respectively) are associated with acute resolving infection; however, they are undetectable in chronic infection. Up to now, cytotoxic T-lymphocyte (CTL) responses could not be determined in the woodchuck. In the present study, we detected virus-specific CTL responses by a CD107a degranulation assay. The splenocytes of woodchucks in the postacute phase of WHV infection (18 months postinfection) were isolated and stimulated with overlapping peptides covering the whole WHcAg. After 6 days, the cells were restimulated and stained for CD3 and CD107a. One peptide (c96-110) turned out to be accountable for T-cell expansion and CD107a staining. Later, we applied the optimized degranulation assay to study the kinetics of the T-cell response in acute WHV infection. We found a vigorous T-cell response against peptide c96-110 with peripheral blood cells beginning at the peak of viral load (week 5) and lasting up to 15 weeks postinfection. In contrast, there was no T-cell response against peptide c96-110 detectable in chronically WHV-infected animals. Thus, with this newly established flow cytometric degranulation assay, we detected for the first time virus-specific CTLs and determined one immunodominant epitope of WHcAg in the woodchuck.
Frank
Ina
I
Institut für Virologie, Universitätsklinikum Essen, Hufelandstr. 55, D-45122 Essen, Germany.
Budde
Claudia
C
Fiedler
Melanie
M
Dahmen
Uta
U
Viazov
Sergei
S
Lu
Mengji
M
Dittmer
Ulf
U
Roggendorf
Michael
M
D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D001483:Base Sequence; D015550:Cell Degranulation / Q000276:immunology; D004195:Disease Models, Animal; D017919:Hepatitis B Virus, Woodchuck / Q000276:immunology*; D019694:Hepatitis B, Chronic / Q000276:immunology* / Q000662:veterinary; D007111:Immunity, Cellular; D052118:Lysosomal-Associated Membrane Protein 1 / Q000276:immunology; D008392:Marmota / Q000276:immunology* / Q000821:virology; D008969:Molecular Sequence Data; D010455:Peptides / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D013997:Time Factors; D019562:Viral Load
D000956:Antigens, Viral; D052118:Lysosomal-Associated Membrane Protein 1; D010455:Peptides