Immunohematologic studies on the SDF-1/CXCR-4 system with monoclonal antibod.

制备了三株单抗，分别命名为IVR7、AI58和THS123，并证明它们能与人CXCR-4转染人COS-7细胞发生特异性反应。THS123可从CXCR-4^+细胞免疫沉淀表观摩尔质量为47kD的组分。流式细胞仪分析显示，大多数造血系和部分非造血系均表达CXCR-4。部分正常外周血单核细胞表达CXCR-4，但中性粒细胞阴性。双色分析显示，大多数T细胞、几乎所有B细胞和所有单核细胞都表达CXCR-4，而NK细胞上几乎检测不到CXCR-4。在分化的辅助性T细胞中，Th2表达CXCR-4，而Th1表达CXCR-4。IL-4还能诱导Th1细胞表达功能性CXCR-4。因此，CXCR-4在造血细胞中的表达不是普遍存在的，而是细胞类型特异性的。HIV-1的进入是由包膜蛋白gp120与CD4和相关的趋化因子受体之一相互作用启动的。虽然推测gp120的V3区参与与趋化因子受体的相互作用，但V3区是否能直接与趋化因子受体结合仍不清楚。利用与HIV-1T、M和双嗜性毒株gp120的V3区相对应的人工合成的V3多肽，我们可以证明T和双嗜性毒株的V3多肽可以直接与CXCR-4结合，这表明gp120的V3区可以自己与相应的趋化因子受体结合，而不需要CD4或gp120的其他结构域。

Three mAbs, termed IVR7, AI58, and THS123, were generated and demonstrated to react specifically with human CXCR-4-transfected COS-7 cells. THSl23 could immunoprecipitate a component with an apparent mol wt of 47 kD from CXCR-4^+ cells. Flow cytometric analysis showed that most of the hematopoietic cell lines and some non-hematopoietic cell lines expressed CXCR-4. A fraction of normal peripheral blood mononulcear cells expressed CXCR-4 but neutrophils were negative. Two color analysis revealed that the majority of but not all T cells, virtually all B cells and all moncytes expressed CXCR-4 while it was hardly detectable on NK cells. As to differentiated helper T cells, Th2 but not Th1 expressed CXCR-4. It was also found that IL-4 could induce expression of functional CXCR-4 on Th1. Thus, expression of CXCR-4 is not ubiquitous but rather cell type-specific in hematopoietic cells.Entry of HIV-1 is initiated by interaction of the envelope protein gp120 with CD4 and one of the relevant chemokine receptors. Although the V3 region of gp120 is speculated to be involved in interaction with chemokine receptors, it is still unclear if the V3 region can directly bind to them. Using synthetic V3 peptides that correspond to the V3 regions of gp120 of T-tropic, M-tropic and dual tropic HIV-1, we could demonstrate that V3 peptides of T-tropic and dual tropic strains but not that of an M-tropic strain could directly bind to CXCR-4, which indicate that the V3 region of gp120 can bind to the relevant chemokine receptor by itself without CD4 or other domains of gp120.