Enhancement of a hepatitis B DNA vaccine potency using aluminum phosphate in mice / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To study antibody response to a hepatitis B DNA vaccine by formulation with aluminum phosphate in mice.</p><p><b>METHODS</b>An eukaryotic expression plasmid inserted HBsAg gene (pcDNA3.1-S) was constructed by cloning technique and the accuracy of the construct was confirmed by restriction enzyme digestion and DNA sequencing, then hepatitis B DNA vaccine formulations were prepared by mixing pcDNA3.1-S with various concentration of aluminum phosphate in 0.9% NaCl. HBsAg expressions were assayed by ELISA in vivo five days after intramuscular injection of pcDNA3.1-S with or without aluminum phosphate. And serum samples were obtained from individual immunized or control mice 6 weeks post injection. Then anti-HBs were assayed in mice sera by ELISA.</p><p><b>RESULTS</b>Five days after intramuscular immunization, the levels of HBsAg expression of groups with aluminum phosphate showed no difference from those of control group in tibialis arterials muscles. In sera, HBsAg could not be detectable in all groups. Intramuscular immunization of BABL/C mice with pcDNA3.1-S mixed aluminum phosphate (0microg, 1microg, 10microg, 50microg, 100microg) 6 weeks later, the P/N values of anti-HBs in sera were 11.54+/-5.60, 11.00+/-6.62, 20.30+/-10.20, 49.18+/-24.40 and 48.68+/-27.78, respectively. It showed that pcDNA3.1-S mixing with aluminum phosphate could increase anti-HBs titers in mice.</p><p><b>CONCLUSION</b>No increase of HBsAg expression was observed by mixing plasmid pcDNA3.1-S with various concentration of aluminum phosphate in vivo. But Intramuscular immunization of BALB/C mice with pcDNA3.1-S mixing aluminum phosphate adjuvant can increase anti -HBs titers. It seemed that aluminum phosphate would be valuable for further investigation as a potential adjuvant of hepatitis B DNA vaccines.</p>

The role of dendritic cell and macrophage in hepatoma antigen-presenting / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To study the role of dendritic cells (DCs) and macrophages, differentiated from the same individual peripheral blood monocytes, in tumor antigen- presenting.</p><p><b>METHODS</b>DCs and macrophages were differentiated from human peripheral blood monocytes by adding both Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) or GM-CSF only. Then they were loaded with tumor antigen at different concentrations and cocultured with autologous T cells in 96-well flat-bottomed microtiter plates for five days at 37 degrees C, 5% CO(2). (3)H-thymine was added before the culture terminated, and twelve hours later, the cells were gathered to test the cpm value.</p><p><b>RESULTS</b>Both DCs and macrophages chased with tumor antigen could strongly stimulate the proliferation of autologous T cells, especially DCs. The stimulation effect with 20 microl/ml antigen was the most remarkable and the cmp values were 11,950.3 +/-1621.8, 8,708.5 +/-176.1, 402.5+/-43.1 in DCs group, Macrophages group, and lymphocytes group, respectively.</p><p><b>CONCLUSION</b>The antigen presenting role of DCs is stronger than that of macrophages from the same individual.</p>

Transient expression of fusion protein with a chimeric HBsAg-HSP70 construct in HepG2 cells / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate transient expression of fusion protein with a chimeric HBsAg-HSP70 construct in HepG2 cells.</p><p><b>METHODS</b>Enkaryotic expression plasmids inserted HBsAg gene or chimeric HBsAg-HSP70 gene were prepared and transfected into HepG2 cells by means of cationic liposome. mRNA were detected by RT-PCR and proteins expressed in the cells were detected by immunocytochemistry 48 hours later. HBsAg in cultured supernatants and cell lysates were assayed by ELISA.</p><p><b>RESULTS</b>Fusion protein (HBsAg-HSP70) transient expression in HepG2 cells were confirmed by RT-PCR, immunocytochemistry or ELISA, but fusion protein was not assayed in cell cultured supernatants by ELISA.</p><p><b>CONCLUSIONS</b>Transfection of HepG2 cells with a chimeric HBsAg-HSP70 construct leads to express fusion protein, but it does not secrete into cell cultured supernatants.</p>