Enhancement of Protein Productivity of Recombinant Hepatitis A Virus VP1 in Stably Transfected Drosophila melanogaster S2 Cells

The effect of DMSO and sodium butyrate on the production of recombinant hepatitis A virus (HAV) capsid protein VP1 was evaluated and optimized in the culture of stably transfected Drosophila melanogaster S2 cells using culture plates and spinner flasks. The effect of DMSO and sodium butyrate was also evaluated to improve the recombinant VP1 production in stably transfected Drosophila S2 cells. A production level of 0.88 mg of recombinant VP1/liter was obtained in the culture-plate culture of stably transfected S2 cells at 6 days after induction with 0.5 mM CuSO4. The supplements of 2% DMSO and 10 mM sodium butyrate at 4 days post-inoculation increased recombinant VP1 accumulation by 141 and 104%, respectively, resulting in 2.17 and 1.7 mg/liter of recombinant VP1 production. In spinner flasks, recombinant VP1 production reached maximum level at 9 days after induction with 0.5 mM CuSO4, with approximately 4.96 mg/liter of recombinant VP1 production level. When 2% DMSO or 10 mM sodium butyrate was added at 5 days post-inoculation, the recombinant VP1 production was increased to 8.35 and 5.85 mg/liter, respectively. However, the synergistic effects of DMSO and sodium butyrate were not observed. These results indicate that DMSO and/or sodium butyrate can be successfully used to improve the recombinant HAV VP1 production in culture plates and spinner flasks.

Study of Cryopreservation of Human Platelets / 中国输血杂志

Using the dimethylsulfoxide (DMSO)with final concentration of 4% as cryoproteclant, the human platelets were stored at - 30℃ and - 80℃ to provide cryopreserved platelets transfusion service. The results of in vivo and in vitro studies showed that DMSO could reversibly inhibit the platelet adhesion and its aggregation induced by the single aggregating agent. The platelet abhe-sion and aggregation could be recovered after washing and removing DMSO. The platelet aggregation caused by the combined aggregating agents wasn't influenced by DMSO. The adhesion, aggregation and resulting hypotonic shock reaction of cryopreserved platelets were used to be lower than those of fresh platelets, independent on the storage timed or 3 months). The quality of the platelets stored at - 80℃ was better than that at - 30℃. Being transfused with the platelets stored at - 80# could raise the platelet counts in patients, and effectively prevent and control the haemorrhage caused by thrombocytopenia.