Bergstedt-Lindqvist S, Moon H B, Persson U, Möller G, Heusser C, Severinson E
Department of Immunology, Stockholm University, Sweden.
Eur J Immunol. 1988 Jul;18(7):1073-7. doi: 10.1002/eji.1830180716.
Mouse interleukin 4 (IL 4) is a T cell-produced lymphokine with multiple effects on different cells types of the hematopoietic lineages. IL 4 has pronounced effects on B lymphocytes, where it induces high levels of IgG1 and IgE secretion in lipopolysaccharide-stimulated cultures that would otherwise secrete predominantly IgG3 and IgG2b (of the non-IgM isotypes). An important question is how IL 4 exerts its effect. Two main possibilities exist: (a) IL 4 instructs uncommitted B lymphocytes to IgG1 and IgE production; (b) IL 4 selects and expands an already precommitted B cell. In this study we show, by the use of limiting dilution analysis, that IL 4 dramatically increases the precursor frequency of IgG1 and IgE-secreting cells with no significant effect on the clone size, clearly suggesting that IL 4 instructs uncommitted B cells to switch to IgG1 and IgE. The fraction of total Ig precursors that can switch to the two isotypes is furthermore high. The high precursor frequency for IgE obtained in the presence of IL 4 further demonstrates that IL 4 is an important modulator of IgE responses.
小鼠白细胞介素4（IL-4）是一种由T细胞产生的淋巴因子，对造血谱系的不同细胞类型具有多种作用。IL-4对B淋巴细胞有显著影响，在脂多糖刺激的培养物中，它能诱导高水平的IgG1和IgE分泌，否则这些培养物主要分泌IgG3和IgG2b（非IgM同种型）。一个重要的问题是IL-4如何发挥其作用。存在两种主要可能性：（a）IL-4指导未定向的B淋巴细胞产生IgG1和IgE；（b）IL-4选择并扩增已经预先定向的B细胞。在本研究中，我们通过有限稀释分析表明，IL-4显著增加了分泌IgG1和IgE细胞的前体细胞频率，而对克隆大小没有显著影响，这清楚地表明IL-4指导未定向的B细胞转换为IgG1和IgE。此外，能够转换为这两种同种型的总Ig前体细胞比例很高。在IL-4存在的情况下获得的高IgE前体细胞频率进一步证明IL-4是IgE反应的重要调节因子。
