Adaptability and purification of dengue-III virus D9964 strain in KMB17 cells and proliferation kinetics of adapted strain / 病毒学报

To select the adaptive strain of Dengue-III virus D9964 strain (China strain) in KMB17 cells, elucidate the biological characteristics and proliferation kinetics of adapted strain,and to lay the foundation for the development dengue inactivated vaccine and attenuated live vaccine. Dengue-III virus D9964 strain was firstly identified by amplification of the type-specific gene segment of dengue virus by RT-PCR, and the titer was determined. The virus was then subcultured in KMB17 cells with 4.0 MOI till completely adaptive to multiply in cell S. After subculturing in KMB17 cells for 10 consecutive passages, the adapted strain was screened, and purified through plaque. Virus titer of each passage was measured by microtitrimetry, and the antigenicity was detected by IFA. The purified virus RNA extraction of 3-8 day cultured from KMB17 cells, was performed to detect the proliferation kinetics of adapted strain. The results showed that after continuous subculture, dengue-III virus D9964 (China) strain could stably proliferate in KMB17 cells, a highly puried virus adapted strain was obtained through plaque purification. Purified strain maintained the good antigenicity with a highest replicating activity during the 5th-6th day.

Expression and Purification of Human Parathyroid Hormone Peptide(1-34) in Escherichia coli / 中国生物工程杂志

Human parathyroid hormone peptide1-34(hPTH1-34) was highly expressed in Escherichia coli by inserting the synthesized hPTH1-34 cDNA into pThioHis, the prokaryotic expression vector. The expressed hPTH1-34 was purified by chelating sepharose immobilized metal ion affinity, reverse and filter chromatographic steps. Its purity was verified above 95% by HPLC. The quality was identified by N-terminal sequencing and MALDI-TOF-MS analysis. In vitro analysis showed the adenylate cyclase of ROS 17/2.8 cells was activated by hPTH1-34.

Site-specific PEGylation of Engineered Cysteine Analogues of Recombinant Human Interleukin-11 / 中国生物工程杂志

Human Interleukin-11(hIL-11)has no Cys residue in its natural form.By site-directed mutagenesis,a Cys residue can be introduced to replace the 1st residue Gly and the rhIL-11 was chemically modified by using 20 kDa mPEG-maleimide conjugated to this site.The mPEG-hIL-11 conjugate was purified and showed a single band on SDS-PAGE with an apparent molecular weight.The biological activity of purified mPEG-hIL-11 was determined using a dependent cell line 7TD1.The remaining biological activity of PEGylated-rhIL-11 was 30% of native rhIL-11,suggesting chemical modification of rhIL-11 by PEG is a promising approach for improving the pharmacological efficacy.