In vitro culture of human peripheral blood monocytes induces hyaluronan binding and up-regulates monocyte variant CD44 isoform expression.
In vitro culture of human peripheral blood monocytes induces hyaluronan binding and up-regulates monocyte variant CD44 isoform expression.
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DOI：
10.4049/jimmunol.156.4.1557
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发表时间：
1996-02
影响因子：
4.4
通讯作者：
M. Levesque;B. F. Haynes
中科院分区：
文献类型：
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作者：
M. Levesque;B. F. Haynes
CD44是一种细胞表面蛋白多糖，与软骨连接蛋白同源，作为透明质酸（HA）的受体。CD44异构体包括未剪接的80- 90 kda标准形式（CD44S）和9个CD44变异外显子（CD44V）的选择性剪接衍生的异构体。在单核细胞上连接CD44亚型可诱导IL-1和tnf - α的产生。此外，CD44单克隆抗体和HA抑制嗜单核细胞的HIV感染，但不抑制T细胞嗜T细胞的HIV感染。为了确定PB淋巴细胞和单核细胞结合HA的能力，并定义和比较PB单核细胞和淋巴细胞上存在的CD44亚型，我们使用CD44单抗、HA- fitc、流式细胞术和Western blot分析来研究PBMC。我们发现新鲜分离的PB单核细胞和淋巴细胞不结合可溶性HA。然而，PBMC体外培养8至16小时后，cd44依赖性HA-FITC与单核细胞结合，而不与淋巴细胞结合。CD44单抗的Western blot和流式细胞术分析显示，高分子量CD44V亚型在培养的单核细胞上选择性表达，而在淋巴细胞上不表达。最后，炎性病变患者的组织巨噬细胞和多核巨细胞在体内表达含有CD44V6-和cd44v9的CD44亚型，提示CD44V的表达与体内炎症部位单核细胞向组织巨噬细胞的分化有关。综上所述，我们的数据表明，PB单核细胞，而不是T淋巴细胞或B淋巴细胞，在体外培养后获得了结合HA和上调CD44V表达的能力。
CD44 is a cell surface proteoglycan homologous to cartilage link protein that serves as a receptor for hyaluronan (HA). CD44 isoforms include an unspliced 80- to 90-kDa standard form (CD44S) and isoforms derived from alternative splicing of nine CD44 variant exons (CD44V). Ligation of CD44 isoforms on monocytes induces the production of IL-1 and TNF-alpha. In addition, CD44 mAbs and HA inhibit HIV infection of monocytes by monocytotropic HIV, but do not inhibit T cell tropic HIV infectivity of T cells. To determine the ability of PB lymphocytes and monocytes to bind HA and to define and compare CD44 isoforms present on PB monocytes and lymphocytes, we studied PBMC using a panel of CD44 mAbs, HA-FITC, flow cytometry, and Western blot analysis. We found that freshly isolated PB monocytes and lymphocytes did not bind soluble HA. However, in vitro culture of PBMC for 8 to 16 h resulted in CD44-dependent HA-FITC binding to monocytes, but not to lymphocytes. Western blot and flow cytometry analyses using CD44 mAbs demonstrated selective expression of high m.w. CD44V isoforms on cultured monocytes, but not on lymphocytes. Finally, tissue macrophages and multinucleated giant cells from patients with inflammatory lesions expressed CD44V6- and CD44V9-containing CD44 isoforms in vivo, suggesting that CD44V expression is associated with differentiation of monocytes to tissue macrophages in vivo in inflammatory sites. Taken together, our data demonstrate that PB monocytes, but not T or B lymphocytes, acquire the ability to bind HA and up-regulate CD44V expression after in vitro culture.