Suwannasom Nittiya, Smuda Kathrin, Kloypan Chiraphat, Kaewprayoon Waraporn, Baisaeng Nuttakorn, Boonla Chanchai, Georgieva Radostina, Bäumler Hans
Charité - Universitätsmedizin Berlin, Institute of Transfusion Medicine, Berlin, Germany.
Gen Physiol Biophys. 2019 Sep;38(5):369-378. doi: 10.4149/gpb_2019021. Epub 2019 Aug 14.
CD33 is a myeloid-associated marker and belongs to the sialic acid-binding immunoglobulin (Ig)-like lectin (Siglec) family. Such types of receptors are highly expressed in acute myeloid leukemia, which could be used in its treatment. CD33 shows high variability in its expression levels with still unknown reasons. Here, we investigated the CD33 expression of monocytes in human blood samples processed at different temperatures and in dependence on their phagocytic activity against opsonized Escherichia coli. The samples were stained by fluorescently labelled anti-human CD14 to specify the monocyte population, anti-human CD33 antibodies to evaluate CD33 expression and analyzed by flow cytometry and confocal laser scanning microscopy. In blood samples kept at 37°C or first pre-chilled at 0°C with subsequent warming up to 37°C, the percentage of CD33-positive monocytes as well as their relative fluorescence intensity was up-regulated compared to samples kept constantly at 0°C. After exposure to E. coli the CD33 relative fluorescence intensity of the monocytes activated at 37°C was 3 to 4 times higher than that of those cells kept inactive at 0°C. Microscopic analysis showed internalisation of CD33 due to its enhanced expression on the surface followed by engulfment of E. coli.
CD33是一种髓系相关标志物，属于唾液酸结合免疫球蛋白（Ig）样凝集素（Siglec）家族。这类受体在急性髓系白血病中高表达，可用于其治疗。CD33的表达水平高度可变，原因尚不清楚。在此，我们研究了在不同温度下处理的人类血液样本中单核细胞的CD33表达情况，以及其对调理素化大肠杆菌的吞噬活性的依赖性。样本用荧光标记的抗人CD14染色以确定单核细胞群体，用抗人CD33抗体评估CD33表达，并通过流式细胞术和共聚焦激光扫描显微镜进行分析。与始终保持在0°C的样本相比，在37°C保存的血液样本或先在0°C预冷随后升温至37°C的血液样本中，CD33阳性单核细胞的百分比及其相对荧光强度均上调。暴露于大肠杆菌后，在37°C激活的单核细胞的CD33相对荧光强度比在0°C保持未激活状态的细胞高3至4倍。显微镜分析显示，由于CD33在表面的表达增强，其发生内化，随后大肠杆菌被吞噬。
