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Objective:To investigate the ability of the anti-PD-1(scFv)/hIL-15 fusion protein(PD-15) to specifically bind to PD-1 in vitro and the effect of the combination of PD-15 with GF-hIL-15Ra-K562(G15Ra-K562) feeder cells to expand NK/T cells. Methods:Overlap PCR was used to construct G15Ra expression vector. pMXs-G15Ra-IP was transfected into K562 by electroporation. G15Ra-K562 feeder cell lines were obtained by limiting dilution method. pUC57-PD-15 was constructed by digestion and ligation. Lipofectamine? 2000 was used to transiently transfect pUC57-PD-15 into HEK293T cells and the conditioned medium containing PD-15 fusion protein was obtained. Density gradient centrifugation was used to obtain human peripheral blood mononuclear lymphocytes(PBMC), and CFSE staining was used to mark active proliferating cells. Flow cytometry was used to detect the ability of PD-15 to specifically bind to PD-1 and its effect on the proliferation of human PBMC and the proportion of different subpopulations of lymphocytes.Results:The feeder cells G15Ra-K562 with high expression of fusion protein G15Ra was successfully constructed. The addition of hIL-15 can increase the ability of G15Ra-K562 to expand human PBMC by more than 5 times( P<0.05). PD-15 fusion protein has PD-1 specific binding ability( P<0.001), combined with G15Ra-K562 can efficiently expand human peripheral blood-derived NK/T cells in vitro( P<0.05). The cells expanded by PD-15 and G15Ra-K562 are mainly natural killing cell, CD8 + T and CD4 + T cells. Conclusions:The PD-15 fusion protein can specifically target the PD-1 molecule and has a strong human peripheral blood-derived NK/T cell expansion ability when combined with G15Ra-K562 feeder cells. These results shed light on selective expansion of PD-1 + lymphocytes in vitro.
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Objective To study plasmid-mediated transfer,plasmid replicon typing,and genetic environment of blaNDM-1 gene in Enterobacteraerogenes(E.aerogenes).Methods E.aerogenes HN-NDM0711 was used as the subject of this research,the transferable properties of plasmid were analyzed by conjugation testing,conjugant was performed stability testing,plasmid type was determined by PCR-based replicon typing (PBRT),downstream and upstream of blaNDM-1 were sequenced using chromosome walking method,genetic context was analyzed by BLASTN and BALSTP,as well as annotated using Vector NTI 11.5.1 software,sequence pipeline graph was made,the sequence was submitted to Genbank through software Banklt.Results The conjugation testing of E.aerogenes pHN-NDM0711 was positive,after positive conjugant was conducted 4-day passage,minimal inhibitory concentrations (MICs) of imipenem and meropenem to all the cloned strains didn't change,blaNDM-1 were all positive.The replicon type was IncA/C;blaNDM-1 gene was localized between ISAba14 and IS91,at upstream of the blaNDM-1,class 1 integron and Tn3 transposon were identified,class 1 integron contained a new mosaic structure of a drug-resistant resistance gene cassette.Conclusion E.aerogenes pHN-NDM071 1,bearing blaNDM-1 gene in IncA/C plasmid,derived from gene recombination under different antimicrobial selection pressure.Antimicrobial use in clinical,industrial and agricultural area should be strictly controlled,so as to reduce the emergence of such bacteria.