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

生成了三种单克隆抗体，分别为IVR7、AI58和THS123，并证明它们与人cxcr -4转染的COS-7细胞特异性反应。THSl23能从CXCR-4^+细胞中免疫沉淀出表观摩尔重量为47 kD的组分。流式细胞术分析显示，大部分造血细胞系和部分非造血细胞系表达CXCR-4。一部分正常外周血单核细胞表达CXCR-4，但中性粒细胞表达阴性。两种颜色分析显示，大部分但不是全部的T细胞、几乎所有的B细胞和所有的单核细胞都表达CXCR-4，而NK细胞几乎检测不到。在分化的辅助T细胞中，Th2表达CXCR-4，而Th1不表达。同时发现IL-4可以诱导Th1上功能性CXCR-4的表达。因此，在造血细胞中，CXCR-4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和一种相关趋化因子受体的相互作用启动的。虽然推测gp120的V3区参与了与趋化因子受体的相互作用，但目前尚不清楚V3区是否可以直接与趋化因子受体结合。通过合成t向、m向和双向HIV-1的gp120 V3区对应的V3肽，我们发现t向和双向株的V3肽可以直接与CXCR-4结合，而m向株的V3区不能直接与CXCR-4结合，这表明gp120的V3区可以独立与相关趋化因子受体结合，而不需要gp120的CD4或其他结构域。

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.