A human B cell line （3D5） that responds specifically to B cell growth factor （BCGF） hasbeen developed by a sequence of Staphylococcus aureus Cowen I activation,EB virus im-mortalization,and cloning.Proliferative r...A human B cell line （3D5） that responds specifically to B cell growth factor （BCGF） hasbeen developed by a sequence of Staphylococcus aureus Cowen I activation,EB virus im-mortalization,and cloning.Proliferative response to PHA-stimulated T cell supernatant（PHA-T-Sup） and nonresponsiveness to rIL-2 stimulation were factors used to screen positivecells.Phenotype analysis with a flow cytometer indicated that:1) 3D5 is a B cell line:100% of the cells were positive for B1 marker and 59% were positive for sIg,while T3and Mo 1 were negative:2) 3D5 is an activated B cell line:both Tac and 4F2 markersof activated （but not of resting） B cells were 100% positive:3) 3D5 expresses high molecularweight BCGF （HMW-BCGF） receptor-associated epitope BA5.3D5 cells proliferated inresponse to cpBCGF stimulation in a dose-dependent manner.HMW-BCGF also induced3D5 cells to proliferate.Interestingly.no proliferation could be detected in the presenceof rIL-2,rIL-4,or rIFN-r.The data show that 3D5 cells are specifically BCGF-responsiveB cells.Using 3D5 cells as target,BCGF activity was detected in crude BCGF preparationsedimented by 85% （NH<sub>4</sub>）<sub>2</sub>SO<sub>4</sub> and chromatographed in a DEAE-Sephadex A-25 column fromPHA-T-Sup.T24 cell supernatant with B cell differentiation factor （BCDF） activity couldnot induce 3D5 cells to differentiate into immunoglobulin-secreting cells.展开更多
In order to improve the catalytic performance of the nitrobenzene hydrogenation rearrangement to prepare p-aminophenol,a bimetallic Pt-Ni/C(PNC)catalyst was synthesized.Taking advantage of the synergistic effect of Ni...In order to improve the catalytic performance of the nitrobenzene hydrogenation rearrangement to prepare p-aminophenol,a bimetallic Pt-Ni/C(PNC)catalyst was synthesized.Taking advantage of the synergistic effect of Ni and Pt to enhance product selectivity and catalytic performance stability,the electrons in Ni are moved to Pt by the electron effect,which affects the catalyst’s ability to activate H_(2)as well as the amount of hydrogen activated.Furthermore,due to the strong Pt(5d)-Ni(3d)coupling effect,Ni can effectively maintain Pt stability in the acidic system and reduce Pt dissolution.The stability of the PNC can be found to be greatly enhanced compared to the Pt/C(PC)catalyst,and p-aminophenol selectivity is greatly enhanced,showing excellent catalytic performance.展开更多
文摘A human B cell line （3D5） that responds specifically to B cell growth factor （BCGF） hasbeen developed by a sequence of Staphylococcus aureus Cowen I activation,EB virus im-mortalization,and cloning.Proliferative response to PHA-stimulated T cell supernatant（PHA-T-Sup） and nonresponsiveness to rIL-2 stimulation were factors used to screen positivecells.Phenotype analysis with a flow cytometer indicated that:1) 3D5 is a B cell line:100% of the cells were positive for B1 marker and 59% were positive for sIg,while T3and Mo 1 were negative:2) 3D5 is an activated B cell line:both Tac and 4F2 markersof activated （but not of resting） B cells were 100% positive:3) 3D5 expresses high molecularweight BCGF （HMW-BCGF） receptor-associated epitope BA5.3D5 cells proliferated inresponse to cpBCGF stimulation in a dose-dependent manner.HMW-BCGF also induced3D5 cells to proliferate.Interestingly.no proliferation could be detected in the presenceof rIL-2,rIL-4,or rIFN-r.The data show that 3D5 cells are specifically BCGF-responsiveB cells.Using 3D5 cells as target,BCGF activity was detected in crude BCGF preparationsedimented by 85% （NH<sub>4</sub>）<sub>2</sub>SO<sub>4</sub> and chromatographed in a DEAE-Sephadex A-25 column fromPHA-T-Sup.T24 cell supernatant with B cell differentiation factor （BCDF） activity couldnot induce 3D5 cells to differentiate into immunoglobulin-secreting cells.
基金funded by the National Natural Science Foundation of China(U20A20119,22078292 and 22008212)。
文摘In order to improve the catalytic performance of the nitrobenzene hydrogenation rearrangement to prepare p-aminophenol,a bimetallic Pt-Ni/C(PNC)catalyst was synthesized.Taking advantage of the synergistic effect of Ni and Pt to enhance product selectivity and catalytic performance stability,the electrons in Ni are moved to Pt by the electron effect,which affects the catalyst’s ability to activate H_(2)as well as the amount of hydrogen activated.Furthermore,due to the strong Pt(5d)-Ni(3d)coupling effect,Ni can effectively maintain Pt stability in the acidic system and reduce Pt dissolution.The stability of the PNC can be found to be greatly enhanced compared to the Pt/C(PC)catalyst,and p-aminophenol selectivity is greatly enhanced,showing excellent catalytic performance.
