Increased Response of Human T-Lymphocytes by Dendritic Cells Pulsed with HPV16E7 and Pleurotus sajor-caju-ß-glucan (PBG).

BACKGROUND: Infection with human papillomavirus type 16 (HPV-16) is known to cause cervical cancer, hence the several HPV therapeutic vaccines are developed in E7 oncoproteins and targeted on cell-mediated immunity. Human dendritic cells (HuDCs) are extensively employed in HPV therapeutic vaccines as the carrier or platform for inducing adaptive immune responses. However, the immunomodulators need to be further investigated for vaccine effects. Gray oyster mushroom (Pleurotus sajor-caju) containing ß-glucans is a potent immunomodulator with potential to be used in vaccines. OBJECTIVE: To study the effect of Pleurotus sajor-caju-ß-glucan Polysaccharides (PBG) on human T-lymphocytes by use of the HuDCs' antigen presentation platform for HPV16 vaccine. METHODS: The HPV16-E7 recombinant proteins were constructed in E. Coli. HuDCs pulsed with E7 peptide were cocultured with the T-lymphocytes treated with and without PBG. The number of T-lymphocytes(CD4; CD8) was detected by flowcytometry, and the viral response of T-lymphocytes was measured via IFN-γ release. RESULTS: The PBG treated group of T-lymphocytes cocultured with the HuDCs pulsed by the HPV16-E7 proteins showed significantly higher numbers of T-lymphocytes and IFN-γ release compared with T-lymphocytes without PBG in vitro. Moreover, a significant improvement in the level of specific IgG neutralizing antibodies to HPV was found in a murine model. Further observed was an increase in the expansion of helper and cytotoxic T-cells and IFN-γ releases in human system. CONCLUSION: PBG treatment of T-lymphocytes could be a useful option for prophylactic and therapeutic vaccines in cervical cancer.

Hepatitis C virus E2 protein encapsulation into poly d, l-lactic-co-glycolide microspheres could induce mice cytotoxic T-cell response.

Hepatitis C virus (HCV) is known to cause hepatitis and hepatocellular carcinoma. E2 envelope glycoprotein of HCV type (HCV-E2) has been reported to bind human host cells and is a major target for developing anti-HCV vaccines. However, the therapeutic vaccine for infected patients still needs further development. The vaccine aims to provide cytotoxic T-cells to eliminate infected cells and hepatocellular carcinoma. Currently, there is no effective HCV therapeutic vaccine because most chronically infected patients rarely generate cytotoxic T-cells, even though they have high levels of neutralizing antibodies. Therefore, the adjuvant must be applied to enhance the efficacy of the therapeutic vaccine. In this study, we constructed HCV1b-E2 recombinant protein, a truncated form of peptide, to combine with an effective vaccine adjuvant and delivery system by using poly d,l-lactic-co-glycolide (PLGA) microspheres. HCV1b-E2 protein was effectively encapsulated into PLGA microspheres (HCV1b-E2-PLGA) as a strategy to deliver an insoluble form of HCV1b-E2 protein. The size and shape of PLGA microspheres were generated properly to carry an insoluble form of viral peptide in vivo. The encapsulated viral protein was slowly and continuously released from PLGA microspheres, which indicated the property of the adjuvant. HCV1b-E2-PLGA can trigger a cell-mediated immune response by inducing an expression of mice CD8+ T-cells. Our results demonstrated that HCV1b-E2-PLGA-immunized mice have a significantly increased CD8+ T-cell number, whereas HCV1b-E2-immunized mice have a lower number of CD8+ T-cells. Moreover, HCV1b-E2-PLGA could induce a specific antibody to viral protein, and the immune cells could secrete IFN-γ, which is a significant cytokine for viral response. Thus, HCV1b-E2-PLGA is shown to have adjuvant property and efficacy in the murine model, which is a good strategy to develop HCV prophylactic and therapeutic vaccines.