Gudmundsson K O, Thorsteinsson L, Gudmundsson S, Haraldsson A
The Blood Bank, National University Hospital, Reykjavik, Iceland.
Scand J Immunol. 1999 Jul;50(1):21-4. doi: 10.1046/j.1365-3083.1999.00553.x.
The contribution of cord blood B lymphocytes to the immune response has been under considerable investigation. Cord blood B cells produce almost no antibodies except of the immunoglobulin (Ig)M isotype, indicating immaturity of the cells or the environment they reside in. The aim of this study was to investigate the number of circulating IgA-, IgM-, IgG-, and IgE-producing cells in cord blood in comparison to adult peripheral blood using the ELISPOT method. Moreover, we studied the effect of transformation with the Epstein-Barr virus (EBV) on the proportion of cells producing different isotypes with or without interleukin (IL)-4. Cord blood had IgM-producing cells circulating predominantly, but also some IgA- and IgG-producing cells, whereas adult peripheral blood contained high amounts of circulating IgA-producing cells and some IgM- and IgG-producing cells. No circulating IgE-producing cells were found in either group. Transformation by EBV caused significant expansion of IgA-, IgM-, and IgG-producing cells in adult peripheral blood, but almost only of IgM-producing cells in cord blood. A low but detectable expansion of IgA- and IgG-producing cells was found. Cells producing IgE were still not found, even after EBV transformation. However, EBV transformation in the presence of IL-4 increased the numbers of IgE-producing cells significantly both in cord blood and adult peripheral blood. These findings indicate that cord blood contains some circulating IgA- and IgG-producing cells that are expanded to some extent after EBV infection. They also indicate that cord blood B cells have a similar capacity for IgE production to adult peripheral blood B cells when appropriately stimulated.
脐带血B淋巴细胞对免疫反应的贡献一直受到广泛研究。脐带血B细胞除了产生免疫球蛋白（Ig）M同型外，几乎不产生抗体，这表明这些细胞或它们所处的环境不成熟。本研究的目的是使用ELISPOT方法，比较脐带血与成人外周血中循环产生IgA、IgM、IgG和IgE的细胞数量。此外，我们研究了用爱泼斯坦-巴尔病毒（EBV）转化对有或无白细胞介素（IL）-4时产生不同同型细胞比例的影响。脐带血中主要循环着产生IgM的细胞，但也有一些产生IgA和IgG的细胞，而成人外周血中含有大量循环产生IgA的细胞以及一些产生IgM和IgG的细胞。两组均未发现循环产生IgE的细胞。EBV转化导致成人外周血中产生IgA、IgM和IgG的细胞显著扩增，但脐带血中几乎仅产生IgM的细胞扩增。发现产生IgA和IgG的细胞有少量但可检测到的扩增。即使经过EBV转化，仍未发现产生IgE的细胞。然而，在IL-4存在的情况下进行EBV转化，显著增加了脐带血和成人外周血中产生IgE的细胞数量。这些发现表明，脐带血含有一些循环产生IgA和IgG的细胞，在EBV感染后会有一定程度的扩增。它们还表明，在适当刺激下，脐带血B细胞产生IgE的能力与成人外周血B细胞相似。
