分别以葡萄糖、乳糖为碳源制得干酪乳杆菌LC2W胞外多糖，并对分别分离纯化得到的中性多糖组分体外细胞培养试验结果表明，G1、G2（以葡萄糖为碳源经LC2W发酵分离纯化制备两种均一多糖）和L1、L2（以乳糖为碳源经LC2W发酵分离纯化制备两种均一多糖）均无细胞毒性，在5~80 μg/mL的浓度范围内，L1对B淋巴细胞增殖的抑制作用比G1强，具有明显的剂量效应，其抑制作用与浓度呈负相关；与此相反，在5~80 μg/mL的浓度范围内，G2对B淋巴细胞增殖抑制作用比L2强，表现为明显的剂量效应，其抑制作用与浓度呈正相关。碳源的改变会影响干酪乳杆菌LC2W胞外多糖的组成，并引起其生理活性产生差异。

EPS synthesized by L.casei LC2W from different carbon sources (glucose or lactose) were fractionated. The neutral polysaccharides G1 and G2 were two kinds neutral polysaccharides synthesized by L.casei LC2W using glucose as carbon source. Another two kinds of neutral polysaccharides synthesized by L.casei LC2W using lactose as carbon sources were named as L1 and L2. All the two kinds of polysachharides showed little cytotoxicity to lymphocytes cultured in vitro. On the contrary, all of the 4 EPS fractions demonstrated strong inhibitory activity for the proliferation of B-lymphocytes stimulated by bacterial liposaccharides in vitro. In the range of 5~80 μg/mL, the inhibitory activities of G1 and L1 to the proliferation of B-lymphocytes were negatively correlated to the concentration of EPS. And the inhibitory activities of G2 and L2 were positively correlated to the concentration of EPS. The carbon sources in the growth medium might be a decisive factor for the composition and even the bioactivity of the EPS synthesized by L. casei LC2W.

科技部“十二五”科技支撑计划（2012BAD28B07）；上海市科委科技开发项目（12DZ2281400）