Rybski J A, Lause D B, Reese A C
Department of Cell and Molecular Biology, Medical College of Georgia, Augusta 30912.
J Leukoc Biol. 1989 Jan;45(1):35-45. doi: 10.1002/jlb.45.1.35.
Macrophages are important positive and negative regulators of both primary and secondary antibody responses, and their activity may, in turn, be controlled by soluble mediators secreted by other cells. Fibronectin is a 440,000 dalton normal constituent of plasma and extracellular membranes that acts through macrophages to inhibit mitogen- and alloantigen-stimulated lymphoproliferation. We examined the effect of Fn on the antigen-stimulated lymphoproliferative and antibody responses in cells from trinitrophenol-derivitized keyhole limpet hemocyanin (TNP-KHL) primed rats. Fn in concentrations equivalent to normal plasma levels inhibited TNP-KLH-stimulated lymphoproliferation by unseparated lymph node leukocytes. When the experiment was repeated using purified lymph node T cells and added thioglycollate-induced peritoneal exudate macrophages or splenic adherent macrophages, Fn alone and TNP-KLH alone stimulated lymphoproliferation, but in combination they were strongly inhibitory. The effect was not due to decreased lymphocyte viability in the presence of both TNP-KLH and Fn. Nor was it due to complexes between TNP-KLH and Fn or to a simple alteration in the kinetics of lymphoproliferation. Fn had to be present with the TNP-KLH within the 1st hour of incubation. If macrophages were coincubated with TNP-KLH and Fn for 24 h, washed, and added to enriched T cells, inhibition was equivalent to that seen with continuous coculture. Similarly, coculture of TNP-KLH and Fn inhibited both total immunoglobulin and TNP-KLH-specific antibody synthesis at optimal concentrations of splenic adherent cells. However, at suboptimal levels of splenic macrophages, the combination was synergistic, stimulating more total immunoglobulin synthesis than either TNP-KLH or Fn alone. These data suggest that the inhibitory effect was dependent upon the concentration and phenotype of macrophages present in culture.
巨噬细胞是初次和再次抗体应答的重要正性和负性调节因子，反过来，其活性可能受其他细胞分泌的可溶性介质控制。纤连蛋白是血浆和细胞外膜的一种440,000道尔顿的正常成分，它通过巨噬细胞发挥作用，抑制有丝分裂原和同种抗原刺激的淋巴细胞增殖。我们研究了纤连蛋白对三硝基苯酚衍生的钥孔戚血蓝蛋白（TNP-KHL）致敏大鼠细胞中抗原刺激的淋巴细胞增殖和抗体应答的影响。与正常血浆水平相当浓度的纤连蛋白抑制未分离的淋巴结白细胞受TNP-KLH刺激的淋巴细胞增殖。当使用纯化的淋巴结T细胞以及添加巯基乙酸盐诱导的腹腔渗出巨噬细胞或脾黏附巨噬细胞重复该实验时，单独的纤连蛋白和单独的TNP-KLH均可刺激淋巴细胞增殖，但二者共同作用时则具有强烈的抑制作用。该效应并非由于同时存在TNP-KLH和纤连蛋白时淋巴细胞活力降低所致。也不是由于TNP-KLH与纤连蛋白之间形成复合物或淋巴细胞增殖动力学的简单改变。纤连蛋白必须在孵育的第1小时内与TNP-KLH同时存在。如果巨噬细胞与TNP-KLH和纤连蛋白共孵育24小时，洗涤后加入富集的T细胞，抑制作用与持续共培养时相当。同样，在脾黏附细胞的最佳浓度下，TNP-KLH和纤连蛋白的共培养抑制总免疫球蛋白和TNP-KLH特异性抗体的合成。然而，在脾巨噬细胞亚最佳水平时，二者组合具有协同作用，刺激产生的总免疫球蛋白合成比单独的TNP-KLH或纤连蛋白更多。这些数据表明，抑制作用取决于培养中存在的巨噬细胞的浓度和表型。
