Van Tol M J, Zijlstra J, Heijnen C J, Kuis W, Zegers B J, Ballieux R E
Eur J Immunol. 1983 May;13(5):390-7. doi: 10.1002/eji.1830130508.
Mononuclear cells isolated from human cord blood (CBL) of full-term neonates were stimulated in vitro with a dose range of T cell-dependent antigens, i.e. ovalbumin or sheep erythrocytes, and tested for the capacity to mount an antigen-specific plaque-forming cell (PFC) response. Both of the antigens used induced in CBL a PFC response with the same kinetics of PFC formation and of the same magnitude as found in cultures of adult peripheral blood lymphocytes (PBL). However, optimal PFC responses in CBL were obtained at a hundredfold lower concentration of the antigens compared with the optimal antigen doses for the induction of a PFC response in adult PBL. This phenomenon was further investigated with respect to the antigen dose dependency of the activation of neonatal B cells and neonatal regulatory T cells. The induction of a PFC response in CBL at antigen concentrations that were suboptimal for adult PBL showed a correlation with the particular antigen dose requirements for the activation of B cells and T helper cells in neonates. Furthermore, the findings suggest that the decrease of the PFC response in CBL stimulated with supraoptimal doses of antigen was not caused by the induction of unresponsiveness at the B cell level or by interference of pregnancy-associated substances with the PFC response, but was rather the result of the activation of antigen-specific T suppressor cells. Neonatal T suppressor cells were activated at antigen concentrations that generated T helper activity in the adult. Thus, although neonatal B cells possess the intrinsic capacity to mature into antigen-specific PFC, the conditions for effective activation of neonatal T cells regulating the B cell response differ from those for the activation of adult regulatory T cells.
从足月新生儿的人脐带血（CBL）中分离出的单核细胞，在体外使用一系列剂量的T细胞依赖性抗原（即卵清蛋白或绵羊红细胞）进行刺激，并检测其产生抗原特异性空斑形成细胞（PFC）反应的能力。所使用的两种抗原在CBL中均诱导出PFC反应，其PFC形成动力学与在成人外周血淋巴细胞（PBL）培养物中发现的相同，且反应强度相同。然而，与诱导成人PBL产生PFC反应的最佳抗原剂量相比，CBL中获得最佳PFC反应所需的抗原浓度要低一百倍。针对新生儿B细胞和新生儿调节性T细胞激活的抗原剂量依赖性，对这一现象进行了进一步研究。在对成人PBL而言次优的抗原浓度下，CBL中PFC反应的诱导与新生儿B细胞和T辅助细胞激活所需的特定抗原剂量要求相关。此外，研究结果表明，用超最佳剂量抗原刺激的CBL中PFC反应的降低，不是由B细胞水平上无反应性的诱导或妊娠相关物质对PFC反应的干扰引起的，而是抗原特异性T抑制细胞激活的结果。新生儿T抑制细胞在能在成人中产生T辅助活性的抗原浓度下被激活。因此，尽管新生儿B细胞具有成熟为抗原特异性PFC的内在能力，但调节B细胞反应的新生儿T细胞有效激活的条件与成人调节性T细胞激活的条件不同。
