Han S B, Yoon Y D, Ahn H J, Lee H S, Lee C W, Yoon W K, Park S K, Kim H M
Biopotency Evaluation Laboratory, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 52 Oundong, Yusong, Taejon 305-333, South Korea.
Int Immunopharmacol. 2003 Sep;3(9):1301-12. doi: 10.1016/S1567-5769(03)00118-8.
We investigated the mechanism of the immunomodulatory action of polysaccharide (ASP) isolated from a cell culture of Acanthopanax senticosus. ASP was found to directly increase the proliferation and differentiation of B cells, and the cytokine production of macrophage, but not the proliferation and cytokine production of T cells. Since ASP cannot penetrate the cell membrane due to its large molecular mass, such cellular activation may be caused by the surface binding of ASP to receptors expressed on B cells and macrophages. The possibility that TLRs, which are known to be involved in immune-related responses, may be the receptor(s) of ASP was investigated. The immunomodulating activities of ASP on the B cells and macrophages of C3H/HeJ mice, expressing a defective toll-like receptor (TLR)-4, were decreased versus the corresponding cells from C3H/HeN mice. In addition, the activities of ASP on B cells and macrophages were significantly reduced by treating the cells with antibodies to TLR4 and TLR2 prior to ASP, suggesting that both of them are the possible receptors of ASP. The ligation of TLRs induced by ASP was able to activate mitogen-activated protein kinases (MAPKs), such as Erk1/2, p38 and JNK, and the transcription factor NF-kappaB. Although ASP was shown to activate the TLR signaling cascades in the same manner as lipopolysaccharide (LPS), these two could be differentiated by the finding that polymyxin B (PMB), a specific inhibitor of LPS, did not significantly affect the activities of ASP on B cells and macrophages. Taken together, our results demonstrate that ASP, isolated from a cell culture of A. senticosus, activates B cells and macrophages by interacting with TLRs and leading to the subsequent activation of mitogen-activated protein kinases and NF-kappaB.
我们研究了从刺五加细胞培养物中分离出的多糖（ASP）的免疫调节作用机制。发现ASP可直接促进B细胞的增殖和分化，以及巨噬细胞的细胞因子产生，但对T细胞的增殖和细胞因子产生没有影响。由于ASP分子量较大无法穿透细胞膜，这种细胞激活可能是由ASP与B细胞和巨噬细胞表面表达的受体结合所致。我们研究了已知参与免疫相关反应的Toll样受体（TLR）可能是ASP受体的可能性。与C3H/HeN小鼠的相应细胞相比，表达缺陷型Toll样受体4（TLR-4）的C3H/HeJ小鼠的B细胞和巨噬细胞上，ASP的免疫调节活性降低。此外，在加入ASP之前用抗TLR4和TLR2抗体处理细胞，可显著降低ASP对B细胞和巨噬细胞的活性，表明它们两者都可能是ASP的受体。ASP诱导的TLR连接能够激活丝裂原活化蛋白激酶（MAPK），如Erk1/2、p38和JNK，以及转录因子NF-κB。尽管ASP与脂多糖（LPS）一样能激活TLR信号级联反应，但这两者可通过以下发现加以区分：LPS的特异性抑制剂多粘菌素B（PMB）对ASP对B细胞和巨噬细胞的活性没有显著影响。综上所述，我们的结果表明，从刺五加细胞培养物中分离出的ASP通过与TLR相互作用，进而激活丝裂原活化蛋白激酶和NF-κB，从而激活B细胞和巨噬细胞。
