Iho S, Takahashi T, Kura F, Sugiyama H, Hoshino T
J Immunol. 1986 Jun 15;136(12):4427-31.
1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) dose-dependently suppressed immunoglobulin (Ig) production of human B cells, as evaluated by IgG-plaque-forming cells (IgG-PFC) in the culture of pokeweed mitogen (PWM)-activated B cells. Similar suppressive effect of 1,25(OH)2D3 on Ig production of B cells was observed in the Staphylococcus aureus Cowan I(SAC)-induced Ig-producing system. The mean percentage of inhibitions at a concentration of 10(-9) M were 60.0 +/- 8.2% (mean +/- SE, n = 6) and 65.1 +/- 4.7% (n = 10) in PWM- and SAC-stimulated cultures, respectively. The suppression was strongly exhibited only when 1,25(OH)2D3 was added at the start of the 6-day culture, accompanied by a decrease in DNA synthesis of B cells in both culture systems. On the other hand, the addition of 1,25(OH)2D3 on day 4, when DNA synthesis reached at plateau and IgG-PFC began to be detectable, had no noticeable affect on either the number of PFC or DNA synthesis of B cells. Furthermore, 1,25(OH)2D3 suppressed Ig production even when B cells were exposed to the agent for 4 hr after the activation with PWM or SAC, but not before the activation. These results indicate that 1,25(OH)2D3 inhibits B cell proliferation before differentiation to Ig-secreting cells, consequently reducing Ig production; and that its action appears to be mediated by the cytosol receptors expressed on activated B cells. Thus, the agent may serve as an immunoregulating hormone in vivo, as well as in vitro.
1,25 - 二羟基维生素D3（1,25(OH)2D3）呈剂量依赖性地抑制人B细胞免疫球蛋白（Ig）的产生，这是通过在商陆有丝分裂原（PWM）激活的B细胞培养中IgG斑形成细胞（IgG - PFC）来评估的。在金黄色葡萄球菌考恩I（SAC）诱导的Ig产生系统中也观察到了1,25(OH)2D3对B细胞Ig产生的类似抑制作用。在PWM和SAC刺激的培养物中，浓度为10(-9) M时的平均抑制百分比分别为60.0 +/- 8.2%（平均值 +/- 标准误，n = 6）和65.1 +/- 4.7%（n = 10）。仅在6天培养开始时添加1,25(OH)2D3时才强烈表现出这种抑制作用，同时两个培养系统中B细胞的DNA合成均减少。另一方面，在第4天DNA合成达到平台期且开始检测到IgG - PFC时添加1,25(OH)2D3，对PFC数量或B细胞的DNA合成均无明显影响。此外，即使B细胞在用PWM或SAC激活后暴露于该试剂4小时，1,25(OH)2D3也会抑制Ig产生，但在激活前暴露则不会。这些结果表明，1,25(OH)2D3在B细胞分化为Ig分泌细胞之前抑制其增殖，从而减少Ig产生；并且其作用似乎是由激活的B细胞上表达的胞质受体介导的。因此，该试剂可能在体内和体外均作为一种免疫调节激素发挥作用。
