Xia X, Li L, Choi Y S
Alton Ochsner Medical Foundation Laboratory of Cellular Immunology, New Orleans, LA 70121.
J Immunol. 1992 Jan 15;148(2):491-7.
IL-3 is a well known hemopoietic cell growth and differentiation factor. However, its functional role in normal B cell differentiation has not been established. We have investigated the effect of IL-3 on the growth and differentiation of human B cells. IL-3 enhanced the proliferation of Staphylococcus aureus Cowan 1 strain-stimulated B cells. The optimal time of IL-3 to stimulate B cell growth was on day 2 to day 3, suggesting that IL-3 was a B cell growth factor acting in the late stage. IL-3 synergized with IL-2 to enhance B cell proliferation and differentiation. Pretreatment of B cells with IL-3 for more than 3 days increased the expression of IL-2R on B cells. However, pretreatment of B cells with IL-2 did not alter the subsequent response to IL-3, suggesting that the synergy between IL-2 and IL-3 may be attributed to the up-regulation of IL-2 response by IL-3. In addition, pretreatment of B cells with IL-4 decreased subsequent response of B cells to IL-3 as well as IL-2, suggesting that IL-3- and IL-2-responding cells passed a similar way during the early stage of B cell activation. It appears that IL-3 and IL-6 mediate normal B cell differentiation via separate mechanisms. IL-3-induced B cell differentiation was mainly mediated by increasing cell growth, whereas IL-6 induced B cell differentiation without affecting proliferation.
白细胞介素-3是一种众所周知的造血细胞生长和分化因子。然而，其在正常B细胞分化中的功能作用尚未明确。我们研究了白细胞介素-3对人B细胞生长和分化的影响。白细胞介素-3增强了金黄色葡萄球菌考恩1菌株刺激的B细胞的增殖。白细胞介素-3刺激B细胞生长的最佳时间是在第2天到第3天，这表明白细胞介素-3是一种在后期起作用的B细胞生长因子。白细胞介素-3与白细胞介素-2协同作用以增强B细胞的增殖和分化。用白细胞介素-3预处理B细胞超过3天会增加B细胞上白细胞介素-2受体的表达。然而，用白细胞介素-2预处理B细胞并不会改变其随后对白细胞介素-3的反应，这表明白细胞介素-2和白细胞介素-3之间的协同作用可能归因于白细胞介素-3对白细胞介素-2反应的上调。此外，用白细胞介素-4预处理B细胞会降低B细胞随后对白细胞介素-3以及白细胞介素-2的反应，这表明对白细胞介素-3和白细胞介素-2有反应的细胞在B细胞激活的早期阶段通过类似的途径。看来白细胞介素-3和白细胞介素-6通过不同的机制介导正常B细胞的分化。白细胞介素-3诱导的B细胞分化主要通过增加细胞生长来介导，而白细胞介素-6诱导B细胞分化但不影响增殖。
