Cloning and expression of Sj423 gene encoding the egg-shell precursor protein of Schistosoma japonicum / 中国人兽共患病学报

The gene fragment encoding the egg-shell precursor protein of Schistosoma japonicum was amplified with RT-PCR by using PCR primer designed according to the 423 bp cDNA fragment of the Philippine strain of S.japonicum, the corresponding mDNA fragment of Chinese strain as template and then the 5' and 3' ends of this gene cDNA were amplified with 5' RACE and 3' RACE by using a series of primers designed according to the result of sequencing. Result of sequence analysis showed that this fragment, named as Sj423, contained a complete open reading frame (ORF) of gene encoding the egg-shell precursor protein of S.japonicum.(Chinese strain). As demonstrated by sequencing analysis. No intron could be detected in this gene fragment. This gene was subsequently expressed in E.coli after cloning into the expression vector pET28c(+). The molecular mass of the expressed product of this gene was 20.9 kDa as revealed by SDS-PAGE analysis, and Western blot analysis showed that the recombinant protein expressed could react well with the rabbit antiserum against the worm antigen of S.japonicum;indicating the good antigenicity of this expressed product.

Observations on protective immunity in mice induced by recombinant Schistosoma japonicum Sj14FABP through several adjuvant formulations / 中国血吸虫病防治杂志

Objective To test the protective immunity in mice induced by recombinant Schistosoma japonicum Sj14FABP through several adjuvant formulations. Methods The recombinant Schistosoma japonicum Sj14FABP was prepared by expression in E. coli as a GST fusion protein (rSj14/GST) and used to vaccinate outbred Kunming mice by using complete Freund's adjuvant (FCA)/incomplete Freund's adjuvant (FIA), Bacillus Calmette-Guerin (BCG) and the immunostimulating complex (ISCOM) as adjuvant respectively. Results The purified recombinant protein rSj14/GST was immunogenic in mice, and 34.3% and 36.0% worm reduction rates were obtained in outbred Kunming mice immunized intradermally with BCG adjuvant and immunized subcutaneously with ISCOM adjuvant respectively, compared with non-vaccinated control group. However, intramuscularly vaccination with rSj14/GST in FCA/FIA was not protective, although the high level of IgG antibody was induced. Conclusion Both BCG and ISCOM are suitable adjuvants for rSj14/GST.

Construction of Phage Display cDNA Library from Adult Worms of Schistosoma japonicum / 中国寄生虫学与寄生虫病杂志

Objective To screen protective antigen genes and construct the T7 phage display library from adult worms of Schistosoma japonicum.Methods Total RNA was extracted from adult worms of S.japonicum by Trizol reagent and mRNA was isolated from the total RNA.The ds cDNA was synthesized by reverse transcription using random primer.Directional EcoRⅠ/HindⅢ linkers were ligated into the ends of ds cDNA and the ds cDNA was digested with EcoRⅠand HindⅢ,which resulted in ds cDNA with EcoRⅠand HindⅢ adhering ends.The digested ds cDNA fragments longer than 300 bp in length were fractionated and ligated into T7 Select 10-3b vector.After packaging in vitro,the T7 Select 10-3b vector was transformed into BLT5403 to construct the T7 phage display cDNA library.Plaque assay and PCR were used to evaluate the library.Seven known objective genes of S.japonicum were screened by PCR to detect the representation of the library.Result Primary library capacity was 4.98?106 pfu,and the titer of amplified library was 3.85?1011 pfu/mL.The PCR identification result of 96 clones picked at random showed that recombination rate was 93.8%,in which 95.6% inserted cDNA fragments were longer than 300 bp in length.All the seven known objective genes of S.japonicum were amplified from the library.Conclusion The T7 phage display library from adult worms of Schistosoma japonicum was constructed.

Construction of a T7 phage display cDNA library from lung of Microtus fortis / 中国血吸虫病防治杂志

Objective To construct a T7 phage display cDNA library from the lung of Microtus fortis for further screening the schistosomiasis-resistence-related genes of Microtus fortis. Methods mRNA was isolated from total RNA extracted from the lungs of Microtus fortis by TRIzol reagent, and was used to synthesize double strain cDNA by the reverse transcription. Then the double strain cDNA was given with EcoRⅠ and Hind Ⅲ adhering ends by ligation with the directional EcoRⅠ/Hind Ⅲ linkers and digestion with EcoRⅠ and Hind Ⅲ. The double strain cDNA fragments longer than 300 bp in length were fractionated by the Mini Column, and ligated into the T7 Select 10-3b vector with EcoRⅠ and Hind Ⅲ adhering ends. After packaging in vitro, the recombinant T7 Select 10-3b was transformed into BLT5403 to construct a T7 phage display cDNA library. Results The library constructed here contained 1.5?106 clones and the titer of the amplied library was 1.1?1012 pfu/ml. The PCR identification results of 100 clones picked at random showed that 91% clones were recombinant and 90% of recombinant clones contained cDNA fragments longer than 300 bp in length. Conclusion A T7 phage display cDNA library from the lung of Microtus fortis is successfully constructed.