Low hepatitis B virus-specific T-cell response in males correlates with high regulatory T-cell numbers in murine models.

Hepatitis B virus (HBV) infection shows significant gender-related differences in pathogenesis, disease progression, and development of hepatocellular carcinoma. The gender-associated differences in HBV replication and viral protein levels may be associated with distinct HBV-specific immune responses in the host. In the present study, we examined the impact of gender on HBV-specific immune responses in two different mouse models representing transient and persistent hepadnaviral infection; hydrodynamic injection with the HBV genome mimicked acute HBV infection, whereas the efficacy of therapeutic vaccination was studied in the woodchuck hepatitis virus transgenic mouse model. Consistent with previous reports, significantly higher HBV DNA and protein levels were detected in male compared to female mice. Although hydrodynamic injection with the HBV genome resulted in similar numbers of intrahepatic HBV-specific cluster of differentiation 8-positive (CD8+ ) T cells, their functionality was significantly reduced in males and correlated with higher numbers of intrahepatic regulatory T cells (Tregs). Similar effects were observed in woodchuck hepatitis virus transgenic mice immunized with a DNA prime-recombinant adenovirus boost vaccination protocol. Male mice showed functionally suppressed woodchuck hepatitis virus-specific CD8+ T-cell responses in the liver and significantly higher numbers of intrahepatic Tregs compared to females. Blockade of Treg responses in male mice led to augmented effector functions of specific CD8+ T cells and subsequently improved virus control in both models of transient and persistent hepadnaviral infection. CONCLUSION: The functionality of virus-specific CD8+ T cells in male mice was suppressed by intrahepatic Tregs and inversely correlated with levels of hepadnaviral DNA and viral protein; the induction of intrahepatic Tregs by viral replication and/or protein levels may explain the gender-related differences in the outcomes of HBV infection and limit the success of immunotherapeutic strategies in male patients. (Hepatology 2017;66:69-83).

Enhancement of HCV polytope DNA vaccine efficacy by fusion to an N-terminal fragment of heat shock protein gp96.

Induction of a strong hepatitis C virus (HCV)-specific immune response plays a key role in control and clearance of the virus. A polytope (PT) DNA vaccine containing B- and T-cell epitopes could be a promising vaccination strategy against HCV, but its efficacy needs to be improved. The N-terminal domain of heat shock protein gp96 (NT(gp96)) has been shown to be a potent adjuvant for enhancing immunity. We constructed a PT DNA vaccine encoding four HCV immunodominant cytotoxic T lymphocyte epitopes (two HLA-A2- and two H2-D(d)-specific motifs) from the Core, E2, NS3 and NS5B antigens in addition to a T-helper CD4+ epitope from NS3 and a B-cell epitope from E2. The NT(gp96) was fused to the C- or N-terminal end of the PT DNA (PT-NT(gp96) or NT(gp96)-PT), and their potency was compared. Cellular and humoral immune responses against the expressed peptides were evaluated in CB6F1 mice. Our results showed that immunization of mice with PT DNA vaccine fused to NT(gp96) induced significantly stronger T-cell and antibody responses than PT DNA alone. Furthermore, the adjuvant activity of NT(gp96) was more efficient in the induction of immune responses when fused to the C-terminal end of the HCV DNA polytope. In conclusion, the NT(gp96) improved the efficacy of the DNA vaccine, and this immunomodulatory effect was dependent on the position of the fusion.

Immunogenicity of Multi-Epitope DNA and Peptide Vaccine Candidates Based on Core, E2, NS3 and NS5B HCV Epitopes in BALB/c Mice.

BACKGROUND: Hypervariability of HCV proteins is an important obstacle to design an efficient vaccine for HCV infection. Multi-epitope vaccines containing conserved epitopes of the virus could be a promising approach for protection against HCV. OBJECTIVES: Cellular and humoral immune responses against multi-epitope DNA and peptide vaccines were evaluated in BALB/c mice. MATERIALS AND METHODS: In this experimental study, multi-epitope DNA- and peptide-based vaccines for HCV infection harboring immunodominant CD8+ T cell epitopes (HLA-A2 and H2-Dd) from Core (132-142), NS3 (1073-1081) and NS5B (2727-2735), a Th CD4+ epitope from NS3 (1248-1262) and a B-cell epitope from E2 (412-426) were designed. Multi-epitope DNA and peptide vaccines were tested in two regimens as heterologous DNA/peptide (group 1) and homologous peptide/peptide (group 2) prime/boost vaccine in BALB/c mice model. Electroporation was used for delivery of the DNA vaccine. Peptide vaccine was formulated with Montanide ISA 720 (M720) as adjuvant. Cytokine assay and antibody detection were performed to analyze the immune responses. RESULTS: Mice immunized with multi-epitope peptide formulated with M720 developed higher HCV-specific levels of total IgG, IgG1 and IgG2a than those immunized with multi-epitope DNA vaccine. IFN-γ levels in group 2 were significantly higher than group 1 (i.e. 3 weeks after the last immunization; 37.61 ± 2.39 vs. 14.43 ± 0.43, P < 0.05). Moreover, group 2 had a higher IFN-γ/IL-4 ratio compared to group 1, suggesting a shift toward Th1 response. In addition, in the present study, induced immune responses were long lasting and stable after 9 weeks of the last immunization. CONCLUSIONS: Evaluation of multi-epitope DNA and peptide-vaccines confirmed their specific immunogenicity in BALB/c mice. However, lower Th1 immune responses in mice immunized with DNA vaccine suggests further investigations to improve the immunogenicity of the multi-epitope DNA vaccine through immune enhancers.

No detection of 'high-risk' human papillomaviruses in a group of Iranian women with breast cancer.

The presence of viral DNA in breast cancer cells is controversial. However, some studies have revealed a possible role for the human papillomavirus in the pathogenesis of breast cancer. The aim of the present study was to investigate the presence of HPV-DNA in breast tissue in a group of Iranian women with and without breast cancer and identification of the detected HPV types. Paraffin-embedded specimens from 65 malignant breast cancer cases and 65 cases with benign breast lesions were investigated for presence of HPV-DNA by nested polymerase chain reaction. We found HPV-DNA in 22 (33.8%) of the breast cancer specimens. All non-cancerous specimens were negative. Low and high-risk HPV types, including HPV-6 (26.2%), HPV-16 (1.5%), HPV-35 (1.5%), HPV-52 (1.5%), and HPV-11 (1.5%) were detected in our study. HPV-6 was the most prevalent type in the breast cancer specimens. Although high-risk HPV types have been shown to have a major role in cervix cancer, there have been no data that support the same relevance for other types of malignancies. Furthermore, presence of low-risk HPV types in malignancies still is a matter of debate. The data presented in this study indicates a strong need for epidemiological studies correlating different HPV types in human breast cancer.