Warrington R J, Rutherford W J, Wong S K, Cook J M, Rector E S
Department of Medicine, University of Manitoba, Winnipeg, Canada.
J Immunol. 1989 Oct 15;143(8):2546-52.
The EBV-transformed B cell line JR-2 proliferates in response to partially purified preparations of low m.w. B cell growth factor (LMW-BCGF). Two clones of JR-2 were generated that retained this LMW-BCGF responsiveness, exhibiting similar dose/response characteristics but differing phenotypically. The B10 clone grows as single, discrete, small round cells, whereas D3 grows in aggregates. The clones also differ in the expression of cell surface Ag, D3 being weakly DR+ and strongly CD23+, whereas B10 lacks these Ag. The CD23 on D3 cells binds IgE. Both clones are T9+, 4F2+, B1-, B2- and CALLA-. D3 expresses surface IgG and differentiates in the presence of LMW-BCGF, to secrete IgG. B10 lacks surface and cytoplasmic Ig and fails to differentiate in response to LMW-BCGF. CD23 cannot be induced on B10 by incubation with either LMW-BCGF or IL-4. B10 does not shed CD23 and shed CD23 is not a growth factor for either cloned line. Expression of CD23 on D3 cells is not affected by preincubation with LMW-BCGF. Neither B10 or D3 cells respond to rIL-1, rIL-2, rIL-4, rIL-6, rTNF-alpha/beta, rIFN-gamma, or to high m.w. BCGF (Namalwa), alone or in combination. Both clones absorb BCGF activity and crossover absorptions indicate that the clones remove growth factors required by each other. D3 and B10 both appear therefore to respond selectively to LMW-BCGF. These data suggest that the loss of CD23 from a cloned derivative of the cell line JR-2, although accompanied by considerable phenotypic change, is not associated with the disappearance of LMW-BCGF responsiveness, indicating that CD23 is not the essential receptor for LMW-BCGF.
EB病毒转化的B细胞系JR-2可对低分子量B细胞生长因子（LMW-BCGF）的部分纯化制剂产生增殖反应。产生了两个保留这种LMW-BCGF反应性的JR-2克隆，它们表现出相似的剂量/反应特征，但表型不同。B10克隆以单个、离散的小圆形细胞形式生长，而D3则聚集成团生长。这些克隆在细胞表面抗原的表达上也有所不同，D3弱表达DR且强表达CD23，而B10则缺乏这些抗原。D3细胞上的CD23可结合IgE。两个克隆均为T9+、4F2+、B1-、B2-和CALLA-。D3表达表面IgG，并在LMW-BCGF存在的情况下分化，以分泌IgG。B10缺乏表面和细胞质Ig，且对LMW-BCGF无反应而无法分化。用LMW-BCGF或IL-4孵育均不能在B10上诱导出CD23。B10不释放CD23，且释放的CD23对任一克隆系都不是生长因子。用LMW-BCGF预孵育不影响D3细胞上CD23的表达。B10或D3细胞对rIL-1、rIL-2、rIL-4、rIL-6、rTNF-α/β、rIFN-γ或高分子量BCGF（Namalwa）单独或联合使用均无反应。两个克隆均能吸收BCGF活性，交叉吸收表明这些克隆去除了彼此所需的生长因子。因此，D3和B10似乎都对LMW-BCGF有选择性反应。这些数据表明，细胞系JR-2的一个克隆衍生物中CD23的缺失，尽管伴随着相当大的表型变化，但与LMW-BCGF反应性的消失无关，这表明CD23不是LMW-BCGF的必需受体。
