Knuppe Molecular Urology Laboratory, Department of Urology, School of Medicine, University of California , San Francisco, California 94143 – 0738, USA.
Cytotherapy. 2012 Nov;14(10):1159-63. doi: 10.3109/14653249.2012.729817.
The prevailing school of thought is that mesenchymal stromal cells (MSC) do not express CD34, and this sets MSC apart from hematopoietic stem cells (HSC), which do express CD34. However, the evidence for MSC being CD34(-) is largely based on cultured MSC, not tissue-resident MSC, and the existence of CD34(-) HSC is in fact well documented. Furthermore, the Stro-1 antibody, which has been used extensively for the identification/isolation of MSC, was generated by using CD34(+) bone marrow cells as immunogen. Thus, neither MSC being CD34(-) nor HSC being CD34(+) is entirely correct. In particular, two studies that analyzed CD34 expression in uncultured human bone marrow nucleated cells found that MSC (BMSC) existed in the CD34(+) fraction. Several studies have also found that freshly isolated adipose-derived MSC (ADSC) express CD34. In addition, all of these ADSC studies and several other MSC studies have observed a disappearance of CD34 expression when the cells are propagated in culture. Thus the available evidence points to CD34 being expressed in tissue-resident MSC, and its negative finding being a consequence of cell culturing.
主流观点认为间充质基质细胞（MSC）不表达 CD34，这使得 MSC 有别于表达 CD34 的造血干细胞（HSC）。然而，MSC 是 CD34(-)的证据主要基于培养的 MSC，而不是组织驻留的 MSC，而 CD34(-)HSC 的存在实际上有充分的记录。此外，广泛用于 MSC 鉴定/分离的 Stro-1 抗体是通过使用 CD34(+)骨髓细胞作为免疫原产生的。因此，MSC 是 CD34(-)，HSC 是 CD34(+)都不完全正确。特别是两项分析未培养的人骨髓有核细胞中 CD34 表达的研究发现，MSC（BMSC）存在于 CD34(+) 部分。几项研究还发现，新鲜分离的脂肪来源的 MSC（ADSC）表达 CD34。此外，所有这些 ADSC 研究和其他几项 MSC 研究都观察到细胞在培养中增殖时 CD34 表达消失。因此，现有证据表明 CD34 表达于组织驻留的 MSC，其阴性结果是细胞培养的结果。
