Immunization with HBsAg-Fc fusion protein induces a predominant production of Th1 cytokines and reduces HBsAg level in transgenic mice / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The Fc receptor associated pathway might improve the immune responses against hepatitis B virus (HBV) as previously described by us. In addition, the Flt3 ligand (FL) has been reported to potentiate antigen presenting cells in vivo and may act as a potential adjuvant to boost antigen-specific immune responses. In this study, the immune efficacies of a set of fusion proteins of HBsAg and Fc and/or FL were evaluated in HBsAg transgenic mice.</p><p><b>METHODS</b>The fusion proteins composed of HBsAg and the Fc domain of murine IgG1 (HBsAg-Fc) and/or the Flt3 ligand, and yeast-derived recombinant HBsAg were used as immunogen to immunize HBsAg transgenic mice, respectively. Serum and liver HBsAg levels, serum anti-HBsAg and cytokine profile, and the activities of alanine aminotransferase (ALT)/AST were investigated after immunization.</p><p><b>RESULTS</b>After six injections, the most pronounced decrease in serum and liver HBsAg levels was observed in the HBsAg-Fc immunized group. In addition, serum Th1 cytokines and ALT/AST activities were highest in this group, indicating an effective induction of a favorable cellular immune response. Interestingly, the fusion protein containing HBsAg-Fc and the Flt3 ligand stimulated an alternative Th1-type immune response featured with high level productions of tumor necrosis factor α (TNF-α) and monocyte chemoabstractant protein 1 (MCP-1), causing a more severe cytotoxicity in hepatocytes while showed less effective in reducing serum HBsAg level.</p><p><b>CONCLUSION</b>HBsAg-Fc is effective in eliciting both the humoral and cellular immune responses against HBsAg in HBsAg transgenic mice, which makes it a potential immunogen for the immunotherapy of chronic hepatitis B.</p>

Analysis of the factors effecting the expression efficiency of the green fluorescent protein gene in mouse embryonic stem cells / 第二军医大学学报

Objective: To study the factors effecting the expression of the reporter green fluorescent protein (GFP) gene in the mouse embryo stem cell line R1. Methods: Three different kinds of GFP euko-expression vectors were constructed, and the expression efficiency was contrasted both at mRNA and protein levels after they were integrated into the chromosomes of host cells. Results: At protein level, the GFP expression level of the colonies transfected by the expression vector-pEF-GFP with the promoter of the peptide elongation factor (EF) were significantly higher than that of the colonies transfected by pCMV-GFP with CMV promoter and by pdCMV-GFP with double copies of CMV-GFP expression unit. There was no significant difference between the colonies transfected by pCMV-GFP and pdCMV-GFP. The detection results on mRNA level of GFP had the same tendency as that at protein level. Conclusion: (1) GFP gene expression efficiency controlled by EF promoter is distinctly higher than that by CMV promoter in NIH3T3 and R1 ES cell line.(2) A slight increase of the copy number of the foreign gene expression units in the host chromosome can not make obvious increase of its expression efficiency. (3) The vector express GFP in R1 ES cell line efficiently and stablely is obtained.

Analysis of the factors effecting the expression efficiency of the green fluorescent protein gene in mouse embryonic stem cells / 第二军医大学学报

Objective: To study the factors effecting the expression of the reporter green fluorescent protein (GFP) gene in the mouse embryo stem cell line R1. Methods: Three different kinds of GFP euko-expression vectors were constructed, and the expression efficiency was contrasted both at mRNA and protein levels after they were integrated into the chromosomes of host cells. Results: At protein level, the GFP expression level of the colonies transfected by the expression vector-pEF-GFP with the promoter of the peptide elongation factor (EF) were significantly higher than that of the colonies transfected by pCMV-GFP with CMV promoter and by pdCMV-GFP with double copies of CMV-GFP expression unit. There was no significant difference between the colonies transfected by pCMV-GFP and pdCMV-GFP. The detection results on mRNA level of GFP had the same tendency as that at protein level. Conclusion: (1) GFP gene expression efficiency controlled by EF promoter is distinctly higher than that by CMV promoter in NIH3T3 and R1 ES cell line.(2) A slight increase of the copy number of the foreign gene expression units in the host chromosome can not make obvious increase of its expression efficiency. (3) The vector express GFP in R1 ES cell line efficiently and stablely is obtained.