Thurn A L, Underhill C B
J Cell Physiol. 1986 Mar;126(3):352-8. doi: 10.1002/jcp.1041260305.
The effects of different carbohydrates on cell-to-cell adhesion were examined in an aggregation assay, which consisted of swirling a suspension of cells and monitoring the loss of single cells with a Coulter Counter. Of the carbohydrates tested, only heparin and dextran sulfate induced cell aggregation. This effect occurred in freshly isolated mouse splenocytes and in cultured cells of lymphoid origin (P388, YAA-CI) but not in cell lines of fibroblastic origins (3T3, SV-3T3, BHK, and PY-BHK). Using the YAA-CI cell line for further study, we found that aggregation could be induced by relatively small amounts of heparin (less than 10 micrograms/ml). Binding experiments with 3H-heparin showed that under normal physiological conditions each YAA-CI cell bound approximately 2 X 10(6) molecules of heparin at saturation with a Kd of 3.5 X 10(-7) M. This binding was blocked by both unlabelled heparin and dextran sulfate but not by other carbohydrates. When the pH of the medium was decreased, the heparin-induced aggregation was inhibited, and the Kd of the 3H-heparin binding was increased. In a similar fashion, when the ionic strength of the medium was increased, heparin-induced aggregation was inhibited and the Kd of the interaction was increased. These results suggest that the aggregation is inversely related to the Kd of the interaction and that the binding of heparin to the cell surface is primarily of an ionic nature.
在一项聚集试验中检测了不同碳水化合物对细胞间黏附的影响，该试验包括涡旋细胞悬液并用库尔特计数器监测单个细胞的损失。在所测试的碳水化合物中，只有肝素和硫酸葡聚糖能诱导细胞聚集。这种效应在新鲜分离的小鼠脾细胞和淋巴源性培养细胞（P388、YAA-CI）中出现，但在成纤维细胞源性细胞系（3T3、SV-3T3、BHK和PY-BHK）中未出现。使用YAA-CI细胞系进行进一步研究，我们发现相对少量的肝素（小于10微克/毫升）就能诱导聚集。用³H-肝素进行的结合实验表明，在正常生理条件下，每个YAA-CI细胞在饱和状态下结合约2×10⁶个肝素分子，解离常数为3.5×10⁻⁷M。这种结合被未标记的肝素和硫酸葡聚糖阻断，但不被其他碳水化合物阻断。当培养基的pH值降低时，肝素诱导的聚集受到抑制，³H-肝素结合的解离常数增加。同样，当培养基的离子强度增加时，肝素诱导的聚集受到抑制，相互作用的解离常数增加。这些结果表明，聚集与相互作用的解离常数呈负相关，并且肝素与细胞表面的结合主要是离子性质的。
