Characterization of the HTLV-I receptor

人类T细胞白血病病毒I型(HTLV-I)和人类免疫缺陷病毒I型(HIV-1)对靶细胞类型有相似的趋向性，尤其是对CD4+T细胞。虽然CD4是一种HIV-1受体，但HTLV-I的细胞受体尚不清楚。HTLV-I作为一种无细胞病毒并不能有效地感染细胞，但需要HTLV-I感染细胞和靶细胞之间的细胞对细胞接触。最初，我们使用合胞体形成系统来检测HTLV-I感染。这一系统为我们提供了HTLV-I和HIV-1受体完全独立存在于人T细胞表面的证据。此外，HTLV-I受体似乎与CD4分子无关。我们试图利用该系统制备针对HTLV-I受体的单抗，但尚未获得阻断HTLV-I诱导的合胞体形成的抗体。除了这种细胞间系统，我们还建立了一个实验系统来检测HTLV-I的吸附，因为细胞间更多地受到细胞表面与病毒受体无关的黏附分子的影响。将HTLV-I颗粒浓缩后与靶细胞孵育，用流式细胞仪分析病毒在细胞表面的吸附情况。HTLV-I可以与多种人类细胞系结合，但有几个例外。人抗HTLV-I血清抑制HTLV-I的吸附，提示这些血清含有中和HTLV-I结合的抗体。目前正在使用这些系统努力获得针对HTLV-I受体的单抗。

Human T-cell leukemia virus type-I (HTLV-I) and human immunodeficiency virus type-1 (HIV-1) have a similar tropism for target cell types, especially for CD4+ T cells. Although CD4 is an HIV-1 receptor, the cellular receptor for HTLV-I is not yet known. HTLV-I does not effectively infect cells as a cell free virus, but require a cell-to-cell contact between HTLV-I infected cells and target cells. Initially, we used a syncytium formation system to detect HTLV-I infection. This system provided us an evidence that the receptors for HTLV-I and HIV-1 are totally independently present on the cell surface of human T cells. Furthermore, HTLV-I receptor seemed not to be involved in the CD4 molecule. We tried to make monoclonal antibodies for the HTLV-I receptor by using this system, but an antibody blocking HTLV-I-induced syncytium formation was not obtained yet. Besides such cell-to-cell system, we established an experimental system to detect HTLV-I adsorption, since the cell-to-cell would be more affected by adhesion molecules on the cell surface unrelated to virus receptors. HTLV-I particles were concentrated and incubated with the target cells' and viral adsorption to the cell surface was quatnitated by FACS analysis. HTLV-I could bind a wide range of human cell lines with a few exceptions. Human anti-HTLV-I sera inhibited the HTLV-I adsorption, suggesting that these sera contain antibodies neutralizing HTLV-I binding. Efforts to obtain monoclonal antibodies to the HTLV-I receptor are currently being made using these systems.