Hoffman R, Ferguson R, Simmons R L
J Immunol. 1977 Apr;118(4):1472-9.
Human peripheral blood mononuclear cells were exposed to various concentrations of concanavalin A (Con A) and cytochalasin B (CB). Low concentrations of CB (0.5 to 2.0 microng/ml) augmented, whereas high concentrations of CB (greater than 2.0 microng/ml) inhibited the mitogenic response to Con A when Con A and CB were added at the initiation of culture. Augmented responses could also be found by adding normally inhibitory high concentrations of CB after 72 to 96 hr incubation with Con A. Preincubation of the cells with CB 5 min to 4 hr before adding Con A also resulted in potentiation of the mitogenic response. CB did not increase spontaneous transformation and worked as well in various solvents (dimethyl sulfoxide, acetone, and ethanol). The effect was totally reversible by removing CB before adding Con A. CB had no effect on 3H-Con A binding to cells. The potentiating effect of CB was still evident after removal of CB, Con A, or both from cultrues that had been simultaneously exposed to Con A and CB for at least 2 days. CB augmented the response of human lymphocytes to Con A-adsorbed, x-rayed autologous lymphocytes. In the presence of optimal concentrations of CB, x-ray-damaged cells respond better to Con A; the response to suboptimal and supraoptimal concentrations of Con A is better, and the response with delayed addition of alpha-methyl-D-mannoside is better. CB also potentiates the response of human lymphocytes to pokeweed mitogen and phytohemagglutinin. Direct observation of cells in culture demonstrated the development of huge clusters of cells during mitogenic responses to Con A in the absence of CB. Circumstances which inhibited the mitogenic response to Con A totally prevented the development of cellular aggregates (prolonged incubation with high concentrations of CB). Each of the conditions which augmented the mitogenic response to Con A was accompanied by the formation of multiple small, relatively uniform cellular aggregates. These observations suggest that CB affects cell-cell interaction possibly by affecting distribution of Con A on the cell surface, by affecting cell sruface net negative charge, or by increasing the response to chemotactic stimuli. CB may be acting in some manner to enable certain nonresponsive cells to respond to a mitogenic stimulus, although an increase in the response of individual cells cannot be ruled out.
将人外周血单核细胞暴露于不同浓度的刀豆蛋白A（Con A）和细胞松弛素B（CB）中。当在培养开始时加入Con A和CB时，低浓度的CB（0.5至2.0微克/毫升）增强了对Con A的促有丝分裂反应，而高浓度的CB（大于2.0微克/毫升）则抑制了这种反应。在与Con A孵育72至96小时后加入通常具有抑制作用的高浓度CB，也能发现增强的反应。在加入Con A前5分钟至4小时用CB预孵育人外周血单核细胞，也会导致促有丝分裂反应增强。CB不会增加自发转化，并且在各种溶剂（二甲基亚砜、丙酮和乙醇）中均有同样效果。在加入Con A前去除CB，其作用完全可逆。CB对3H-Con A与细胞的结合没有影响。在同时暴露于Con A和CB至少2天的培养物中，去除CB、Con A或两者后，CB的增强作用仍然明显。CB增强了人淋巴细胞对Con A吸附的、经X射线照射的自体淋巴细胞的反应。在最佳浓度的CB存在下，经X射线损伤的细胞对Con A的反应更好；对次优和超优浓度的Con A的反应更好，并且在延迟添加α-甲基-D-甘露糖苷时的反应也更好。CB还增强了人淋巴细胞对商陆有丝分裂原和植物血凝素的反应。对培养细胞的直接观察表明，在没有CB的情况下，对Con A的促有丝分裂反应过程中会形成巨大的细胞簇。抑制对Con A的促有丝分裂反应的情况完全阻止了细胞聚集体的形成（用高浓度CB长时间孵育）。增强对Con A的促有丝分裂反应的每种条件都伴随着多个小的、相对均匀的细胞聚集体的形成。这些观察结果表明，CB可能通过影响Con A在细胞表面的分布、影响细胞表面净负电荷或增加对趋化刺激的反应来影响细胞间相互作用。CB可能以某种方式使某些无反应的细胞能够对促有丝分裂刺激产生反应，尽管不能排除单个细胞反应性增加的可能性。
