Boldt S, Skinner A M, Kornfeld S
J Clin Invest. 1972 Dec;51(12):3225-34. doi: 10.1172/JCI107149.
We have identified two populations of human lymphocytes differing in responsiveness to the plant mitogen concanavalin A (Con-A). When peripheral blood lymphocytes are passed through a nylon column a population of lymphocytes highly responsive to Con-A adheres to the fibers while a second population of cells relatively unresponsive to Con-A emerges from the column. The untreated peripheral blood lymphocytes are termed "unfiltered" cells while the lymphocytes which pass through the column are termed "filtered" cells. Under standard assay conditions the Con-A-stimulated DNA synthesis is 6.5-fold greater, and the percentage blast formation is four-to fivefold greater in the unfiltered than in the filtered population. Mixing unfiltered with filtered cells fails to induce responsiveness in the latter indicating that a "helper" cell is not involved. The failure of filtered cells to respond to Con-A is specific for that mitogen since both populations respond nearly equally to erythroagglutinating phytohemagglutinin (E-PHA) and the poke weed mitogen (PWM). Binding studies with Con-A-(131)I demonstrate that the unfiltered population possesses approximately three times as many Con-A receptor sites per cell as the filtered cells, although both cell populations bind the mitogen with the same affinity (apparent association constant [K] of 1.67 x 10(6)m(-1)). The relationship between Con-A binding and lymphocyte activation was determined by measuring the effect on DNA synthesis of incubating the two lymphocyte populations with increasing amounts of Con-A. The concentration of Con-A required for half-maximal stimulation of DNA synthesis was 5-14 times greater for the filtered cells. However in the presence of very high Con-A concentrations the filtered cells achieved a maximal rate of DNA synthesis approaching that of the unfiltered population. These data implicate the decreased number of Con-A receptor sites on the filtered cells in their failure to respond to low concentrations of Con-A. A crucial event in the activation of lymphocytes by plant mitogens may be the binding of a critical number of the mitogen molecules to the cell surface.
我们已鉴定出两类对植物有丝分裂原刀豆球蛋白A（Con - A）反应性不同的人淋巴细胞。当外周血淋巴细胞通过尼龙柱时，一类对Con - A高度反应的淋巴细胞会黏附在纤维上，而另一类对Con - A反应相对较弱的细胞则从柱中流出。未经处理的外周血淋巴细胞被称为“未过滤”细胞，而通过柱子的淋巴细胞则被称为“过滤”细胞。在标准检测条件下，Con - A刺激的DNA合成在未过滤细胞中比过滤细胞中高6.5倍，且母细胞形成百分比高4至5倍。将未过滤细胞与过滤细胞混合并不能使后者产生反应性，这表明不涉及“辅助”细胞。过滤细胞对Con - A无反应是该有丝分裂原特有的，因为两类细胞对红细胞凝集植物血凝素（E - PHA）和商陆有丝分裂原（PWM）的反应几乎相同。用Con - A -（131）I进行的结合研究表明，未过滤细胞群体中每个细胞的Con - A受体位点数量约为过滤细胞的三倍，尽管两类细胞群体与该有丝分裂原的结合亲和力相同（表观缔合常数[K]为1.67×10（6）m（-1））。通过测量用不同量的Con - A孵育这两类淋巴细胞群体对DNA合成的影响，确定了Con - A结合与淋巴细胞激活之间的关系。过滤细胞达到DNA合成半最大刺激所需的Con - A浓度比未过滤细胞高5至14倍。然而，在非常高的Con - A浓度下，过滤细胞达到的最大DNA合成速率接近未过滤细胞群体的速率。这些数据表明，过滤细胞中Con - A受体位点数量减少导致其对低浓度Con - A无反应。植物有丝分裂原激活淋巴细胞的关键事件可能是一定数量的有丝分裂原分子与细胞表面的结合。
