Localization of CD8+ cells specific for hepatitis B virus surface protein in the liver of immunized mice.
DNA plasmids are potent inducers of long-lasting antigen-specific CTL responses. Little is known about the distribution of antigen-specific CD8+ T cells in the lymphoid tissue and the non-lymphoid tissue after DNA immunization. HBsAg-specific CD8+ T cells in peripheral blood mononuclear cells, spleen, lymph nodes, and the liver of Balb/c mice have been quantified after injection with a DNA plasmid expressing the major S protein of hepatitis B virus (HBV). The kinetics of CD8+ T-cell responses in the circulation were measured after priming and boosting, showing that antigen-specific CD8+ T cells undergo first expansion and then decline to a sustainable level in the circulation, although the frequencies of HBsAg-specific CD8+ T cells in the circulation were lower than for the spleen. The greater frequencies of HBsAg-specific CD8+ T cells were found in the liver, whereas the largest numbers of antigen-specific CD8+ T cells were found in the spleen. By day 100 after priming, HBsAg-specific CD8+ T cells were still detected in the circulation, the spleen and the liver. After boosting with the same plasmid DNA immunogen, HBsAg-specific CD8+ T cells proliferated quickly and vigorously. By 150 days after boosting, HBsAg-specific memory CD8+ T cells were sustained at higher levels than those recorded after the first, primary injection, both in the spleen and the liver: anti-HBs antibody-secreting plasma cells persisted in the bone marrow and in the spleen, consistent with the detection of anti-HBs antibodies detected in the blood. These findings indicate that DNA immunization has considerable potential for inducing specific T cell responses in the liver and offers a strategy for the development of post-exposure immunotherapy against persistent hepatitis B infections.
D000818:Animals; D001769:Blood / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002452:Cell Count; D006509:Hepatitis B / Q000276:immunology*; D006514:Hepatitis B Surface Antigens / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000276:immunology; D006515:Hepatitis B virus / Q000276:immunology*; D007700:Kinetics; D008099:Liver / Q000166:cytology / Q000276:immunology*; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D013154:Spleen / Q000166:cytology / Q000276:immunology; D019444:Vaccines, DNA / Q000276:immunology
D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D019444:Vaccines, DNA