First Department of Pediatrics, Semmelweis University, Budapest, Hungary.
Biol Blood Marrow Transplant. 2012 Oct;18(10):1608-13. doi: 10.1016/j.bbmt.2012.05.008. Epub 2012 May 18.
Umbilical cord blood (UCB) is a promising alternative for the treatment of hematological malignancies. The lower immune reactivity of UCB lymphocytes is a well-known phenomenon; however, immune tolerance mechanisms are not fully elucidated. Galectin-1 has strong immunosuppressive properties and plays a key role in the regulation of immune reactivity. We aimed to determine the properties of intracellular galectin-1 (Gal-1)-producing cells within CD3, CD4, CD8, regulatory T (Treg), and natural killer (NK) cells in UCB compared to adult peripheral blood (APB). We took peripheral blood samples from 22 healthy adults and cord blood samples from 19 healthy, term neonates. Intracellular Gal-1 expression was determined by flow cytometry in the above subsets. Furthermore, we assessed the prevalence of naive and memory T cells that play a role in the regulation of immune reactivity. We also performed functional analyses to assess the effect of exogenous Gal-1 on the rate of proliferation of T lymphocytes isolated from APB and UCB. The prevalence of intracellular Gal-1-expressing CD3, CD4, CD8, Treg and NK lymphocytes was lower in UCB than in APB. However, their capability to produce Gal-1 reaches the level seen in adults. The prevalence of naive cells was higher, whereas that of central and effector memory T cells was lower in UCB compared with APB. Lower Gal-1-producing cell proportion might be due to the naivety of neonatal lymphocytes, as indicated by the positive correlation detected between the number of CD3 lymphocytes expressing intracellular Gal-1 and the prevalence of memory T cells. The intracellular expression of Gal-1 may be down-regulated in neonatal lymphocytes due to the already reduced immune reactivity of UCB. In contrast with previous findings, our results indicate that the administration of exogenous Gal-1 failed to decrease the rate of proliferation in T lymphocytes isolated from either APB or UCB. This suggests that Gal-1-expressing lymphocytes are unlikely to play a major role in mitigating the immune reactivity of UCB.
脐带血（UCB）是治疗血液系统恶性肿瘤的一种有前途的替代方法。UCB 淋巴细胞的免疫反应较低是一个众所周知的现象；然而，免疫耐受机制尚未完全阐明。半乳糖凝集素-1 具有很强的免疫抑制特性，在调节免疫反应中发挥关键作用。我们旨在确定 UCB 中 CD3、CD4、CD8、调节性 T（Treg）和自然杀伤（NK）细胞内细胞内半乳糖凝集素-1（Gal-1）产生细胞的特性，与成人外周血（APB）相比。我们从 22 名健康成年人和 19 名健康足月新生儿中采集外周血样本。通过流式细胞术在上述亚群中测定细胞内 Gal-1 的表达。此外，我们评估了在调节免疫反应中发挥作用的幼稚和记忆 T 细胞的流行率。我们还进行了功能分析，以评估外源性 Gal-1 对从 APB 和 UCB 分离的 T 淋巴细胞增殖率的影响。UCB 中表达细胞内 Gal-1 的 CD3、CD4、CD8、Treg 和 NK 淋巴细胞的流行率低于 APB。然而，它们产生 Gal-1 的能力达到了成人水平。与 APB 相比，UCB 中幼稚细胞的流行率更高，而中央和效应记忆 T 细胞的流行率更低。UCB 中 Gal-1 产生细胞比例较低可能是由于新生儿淋巴细胞的幼稚性所致，这是由于检测到细胞内表达 Gal-1 的 CD3 淋巴细胞数量与记忆 T 细胞的流行率之间存在正相关关系。UCB 中 Gal-1 表达可能由于 UCB 中免疫反应性降低而受到下调。与先前的发现相反，我们的结果表明，外源性 Gal-1 的给药未能降低从 APB 或 UCB 分离的 T 淋巴细胞的增殖率。这表明表达 Gal-1 的淋巴细胞不太可能在减轻 UCB 的免疫反应中发挥主要作用。
