摘要
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.
A human B cell line (3D5) that responds specifically to B cell growth factor (BCGF) has been 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 positive cells.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 T3 and Mo 1 were negative:2) 3D5 is an activated B cell line:both Tac and 4F2 markers of activated (but not of resting) B cells were 100% positive:3) 3D5 expresses high molecular weight BCGF (HMW-BCGF) receptor-associated epitope BA5.3D5 cells proliferated in response to cpBCGF stimulation in a dose-dependent manner.HMW-BCGF also induced 3D5 cells to proliferate.Interestingly.no proliferation could be detected in the presence of rIL-2,rIL-4,or rIFN-r.The data show that 3D5 cells are specifically BCGF-responsive B cells.Using 3D5 cells as target,BCGF activity was detected in crude BCGF preparation sedimented by 85% (NH_4)_2SO_4 and chromatographed in a DEAE-Sephadex A-25 column from PHA-T-Sup.T24 cell supernatant with B cell differentiation factor (BCDF) activity could not induce 3D5 cells to differentiate into immunoglobulin-secreting cells.
