GEORGE J. M. WEBSTER, STEPHANIE REIGNAT, MALA K. MAINI, SIMON A. WHALLEY, GRAHAM S. OGG, ABIGAIL KING, DAVID BROWN, PETER L. AMLOT, ROGER WILLIAMS, DIEGO VERGANI, GEOFFREY M. DUSHEIKO,1 AND ANTONIO BERTOLETTI.
Incubation Phase of Acute Hepatitis B in Man: Dynamic of Cellular Immune Mechanisms。
HEPATOLOGY 2000;32:1117-1124
After hepatitis B virus (HBV) infection, liver injury andviral control have een thought to result from lysis of in-fectedhepatocytes by virus-specific cytotoxic T cells. Pa-tientsare usually studied only after developing significantliver injury, and so the viral and immune events during theincubation phase of disease have not been defined. During asingle-source outbreak of HBV infection, we identified pa-tientsbefore the onset of symptomatic hepatitis. The dy-namicsof HBV replication, liver injury, and HBV-specificCD81 and CD41 cell responses were investigated fromincubation to recovery. Although a rise in alanine transam-inase(ALT) levels was present at the time of the initial fall inHBV-DNA levels, maximal reduction in virus level occurredbefore significant liver injury. Direct ex vivo quantificationof HBV-specific CD41 and CD81 cells, by using humanleukocyte antigen (HLA) class I tetramers and intracellularcytokine staining, showed that adaptive immune mecha-nismsare present during the incubation phase, at least 4weeks before symptoms. The results suggest that the pat-ternof reduction in HBV replication is not directly propor-tionalto tissue injury during acute hepatitis B in humans.Furthermore, because virus-specific immune responses and significant reductions in viral replication are seen during theincubation phase, it is likely that the immune events central to viral control occur before symptomatic disease.
Lohr HF, Krug S, Herr W, Weyer S, Schlaak J, Wolfel T, Gerken G, Meyer zum Buschenfelde KH.
Quantitative and functional analysis of core-specific T-helper cell and CTL activities in acute and chronic hepatitis B.
Liver 1998 Dec;18(6):405-13
AIMS/BACKGROUND: CD4+ T-helper cell (Th) responses to hepatitis B virus (HBV) core antigen (HBc) are increased during exacerbations in acute and chronic hepatitis B (AHB, CHB) and might influence the induction of CD8+ cytotoxic T lymphocytes (CTL) that are important for viral clearance.
METHODS: HBc-specific proliferative responses and cytokine release of blood mononuclear cells (PBMC) were studied in patients with AHB or CHB, as well as responders and non-responders to interferon-alpha treatment (IFN-R, IFN-NR), by [3H]-thymidine-uptake, enzyme-linked immunosorbent assay (ELISA) and Elispot assay and were compared to peptide HBc18 27-specific CTL precursor frequencies among CD8+ T cells derived from HLA-A2+ patients.
RESULTS: HBc-specific proliferative PBMC responses and Th frequencies were significantly increased in AHB patients compared with untreated CHB patients. PBMC derived from IFN-R showed stronger cellular responses than IFN-NR. Stimulated PBMC from all patient groups secreted significantly more IFN-gamma than IL-4 indicating Th1/Th0 cell responses. Furthermore, in AHB and IFN-R patients, high peptide HBc18-27-specific CTL precursor frequencies closely correlated with strong HBc-specific Th responses, whereas in untreated CHB and IFN-NR patients lower CTL frequencies were observed without correlation to Th activities.
CONCLUSIONS: HBV core-specific Th-cell responses appeared to support efficient CTL induction in patients with viral clearance, whereas in chronic HBV carriers quantitatively insufficient Th and CTL responses were observed. This observation could be important for future therapeutic strategies.
Maini MK, Boni C, Ogg GS, King AS, Reignat S, Lee CK, Larrubia JR, Webster GJ, McMichael AJ, Ferrari C, Williams R, Vergani D, Bertoletti A.
Direct ex vivo analysis of hepatitis B virus-specific CD8(+) T cells associated with the control of infection.
Gastroenterology 1999 Dec;117(6):1386-96
BACKGROUND & AIMS: Cytotoxic T cells have been suggested to be responsible for lysis of hepatitis B virus (HBV)-infected hepatocytes and control of virus infection. The frequency, kinetics, phenotype, and capacity for clonal expansion of circulating HBV-specific CD8 cells were analyzed directly in patients with acute HBV infection to clarify their pathogenetic role.
METHODS: Three HLA-A2 peptide tetramers able to visualize HBV core, envelope, and polymerase epitope-specific cytotoxic T lymphocytes were synthesized and used for flow cytometric analysis of antigen-specific populations.
RESULTS: Tetramer-positive cells specific for the core 18-27 epitope were found at a higher frequency than those specific for polymerase 575-583 and envelope 335-343 epitopes in most patients with acute HBV. The number of HBV-specific CD8 cells was highest during the clinically acute stage of infection and decreased after recovery. These cells expressed an activated phenotype and had an impaired capacity to expand in vitro and to display cytolytic activity in response to peptide stimulation. Recovery of these functions was observed when the frequency of specific CD8 cells decreased, coincident with a progressive decrease in their expression of activation markers.
CONCLUSIONS: This study provides the first ex vivo evidence that the highest frequency of circulating HBV-specific CD8 cells coincides with the clinically acute phase of hepatitis B. These cells exhibit an activated phenotype with limited further proliferative capacity that is restored during recovery.
Boni C, Penna A, Ogg GS, Bertoletti A, Pilli M, Cavallo C, Cavalli A, Urbani S, Boehme R, Panebianco R, Fiaccadori F, Ferrari C.
Lamivudine treatment can overcome cytotoxic T-cell hyporesponsiveness in chronic hepatitis B: new perspectives for immune therapy.
Hepatology 2001 Apr;33(4):963-71
The hepatitis B virus (HBV) cytotoxic T lymphocyte (CTL) response in patients with chronic HBV infection is generally weak or totally undetectable. This inability to mount protective CTL responses is believed to be a crucial determinant of viral persistence, and its correction represents an important objective of immune therapies for chronic hepatitis B. However, amplification of CTL responses in vivo may be ineffective if HBV-specific CD8 cells are either absent or nonresponsive to exogenous stimulation. In this study, we asked whether antiviral treatments able to inhibit viral replication and to reduce viral and antigen load can successfully reconstitute CTL responses creating the appropriate conditions for their therapeutic stimulation. For this purpose, the HBV-specific CTL response before and during lamivudine therapy was studied longitudinally in 6 HLA-A2-positive patients with HBeAg+ chronic hepatitis B. Both HBV-specific cytotoxic T cell activity measured by chromium release assay on peptide stimulation in vitro and CD8+ T cell frequency measured ex vivo by HLA-A2/peptide tetramer staining were significantly augmented by lamivudine therapy. This enhancement followed the reconstitution of CD4 reactivity and the decline of viral load induced by therapy. Our study shows that lamivudine treatment in chronic hepatitis B can restore CTL reactivity, making CTL susceptible to exogenous stimulation. This effect may enhance the probability that T cell-based immune therapies delivered after lamivudine treatment can successfully reconstitute a protective CTL response able to cure chronic HBV infection.
3）HVB特异性与非特异性免疫不同组合模式决定HBV感染者不同的预后模式
A）HVB特异性免疫合适+非特异性免疫无/低------》健康人隐性HBV感染而自然康复
B）HVB特异性免疫亚合适+非特异性免疫有（TH0、TH1）------》急性肝炎、重症肝炎
C）HVB特异性免疫无+非特异性免疫无------》健康HBV携带者
D）HVB特异性免疫低/无+非特异性免疫有（TH2、TH3）------》慢性肝炎、肝硬化
E）HVB特异性免疫低/无+非特异性免疫低下（NK和NK-T均低下）------》肝癌
Bertoletti A, Maini MK.
Protection or damage: a dual role for the virus-specific cytotoxic T lymphocyte response in hepatitis B and C infection?
Curr Opin Microbiol 2000 Aug;3(4):387-92
During infection with hepatitis B or C viruses, cytotoxic T lymphocytes (CTLs) have been implicated as both the mediators of protection and the principal effectors of liver pathology. Recent studies have allowed an investigation of the relationship between virus-specific CTL responses, liver damage and viral replication. In the presence of an efficient virus-specific CTL response, a scenario is emerging where inhibition of viral replication can be independent of liver pathology. We discuss the possibility that an inadequate CTL response--unable to control viral replication--may contribute to liver pathology not only directly but also via the recruitment of non-virus-specific T cells.