More than 170 million people worldwide are chronic HCV (Hepatitis C virus) carriers, and about 30% of them will develop progressive liver disease, such as cirrhosis and hepatocellular carcinoma. A combination of pegylated interferon-α with ribavirin, the standard treatment for HCV infection, has been effective in fewer than 50% of patients infected with HCV genotype 1. A strong T cell response against the nonstructural protein 3 (NS3) is important for recovery from acute HCV infection, and an early multi-specific CD4+ helper and CD8+ cytotoxic T cell response is critical for HCV clearance. In the present study, we successfully constructed a genetically modified Bifidobacterium longum (B. longum) displaying recombinant HCV-NS3 peptides containing some CD4 and CD8 epitopes located in the HCV-NS3 region as an oral vaccine against chronic HCV infection. The oral administration of this vaccine could induce NS3-specific immune responses in mice through intestinal mucosal immunity. Our findings suggest that this novel oral vaccine has great potential as a novel oral vaccine against chronic HCV infection.
The use of low-multiplicity infection of 293 cells in static culture with regular medium replacement was investigated for efficient large-scale production of adenovirus vectors for gene therapy applications. An adenovirus vector carrying the enhanced green fluorescent protein gene (Ad EGFP) was used to infect 293-F cells at a low multiplicity of infection (MOI) of 0.00001-0.1 transductional unit (TU) cell -1 . The cells, which have the ability to grow in suspension, were incubated in T-flasks and the serum-free culture medium was replaced with fresh medium via centrifugation every 2 days. Because only a small proportion of cells were initially infected at low MOIs (\1 TU cell -1 ), uninfected cells continued to grow until they were infected by progeny adenoviruses released from previously infected cells. When 293-F cells at a relatively low density of 1 9 10 5 cells cm -3 were infected with Ad EGFP at a low MOI of 0.001 TU cell -1 , the vector yield was 2.7-fold higher than the maximum yield obtained with high-multiplicity infection (MOI = 10 TU cell -1 ) in batch culture. These results indicate that efficient adenovirus vector production using low MOIs is achieved by minimization of either nutrient depletion and/or accumulation of inhibitory metabolites in the culture medium.
E6 and E7 oncogenes of HPV16 were down-regulated by E6 and/or E7 targeting siRNAs, respectively. The expression of p53 and pRb proteins in both the E6 siRNA group and E7 siRNA group was up-regulated compared with those of control groups. The cellular proliferation and apoptosis indexes of E6 and/or E7 siRNA groups were higher than those of controls. In vivo studies showed significant inhibitory effect of E6 and/or E7 siRNA compared with those of control groups, which was consistent with in vitro studies.
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