KILLER CELL SURFACE ANTIGENS--BIOCHEMISTRY AND FUNCTION

自然杀伤(NK)细胞、细胞毒性T淋巴细胞(CTL)和单核细胞 吞噬细胞代表三种主要的细胞介导的细胞毒作用系统 对抗肿瘤。为了剖析细胞表面的重要事件 杀伤细胞的细胞溶解机制，抗杀伤细胞的单抗 已经对表面进行了筛选，以确定是否有能力阻止细胞介导的 缺乏补体时的细胞毒性。一个特定的MAB(RH1-38) 阻断至少三种不同效应细胞介导的细胞毒作用， 包括NK细胞、CTL和单核细胞样细胞(肉豆蔻酸盐 醋酸盐刺激的HL-60)。抗体免疫沉淀来自于 经前刺激的HL-60双分子复合体(195,000和125,000道尔顿) 它在生化上类似于LFA-1抗原，如前所述 CTL上发现的细胞表面抗原。然而，RH1-38与以前不同 描述的抗LFA-1抗体，不抑制效应靶 有约束力的。此外，动力学研究和单细胞细胞毒性测定 已经证明RH1-38阻断了细胞溶解的后期步骤 机制。因此，RH1-38识别功能不同的表位 在LFA-1分子或另一种截然不同的功能重要的分子上 细胞表面分子。 使用已经开发的技术来确定分子量、亚基 结构和表面抗原密度，首席研究人员建议 来检验分子结构和/或 表面抗原密度与细胞毒活性有关。此外, 使用HL-60细胞系作为抗原源，分子识别 到RH1-38将进一步进行生化表征。各种其他的， 非细胞毒性免疫功能将根据以下方面进行检查 用该单抗抑制，以观察其对细胞的影响 免疫反应。在时间允许的情况下，进一步建议：1) 选择的淋巴细胞的分子结构和抗原密度检测 NK缺乏的疾病状态；2)开发将抗原插入 在非细胞毒细胞表面使用抗原重组成 磷脂酰胆碱囊泡；3)开发外源 编码相关抗原的信使核糖核酸的无细胞翻译。 该MAB和其他MAB以及功能重要细胞的特征 他们识别的表面分子可能会产生互补的 导致对细胞表面事件的剖析的信息在 细胞毒性反应。这将使我们更好地了解主机 防御传染病和恶性疾病。(CS)

Natural killer (NK) cells, cytotoxic T lymphocytes (CTLs) and mononuclear phagocytes represent three major systems of cell-mediated cytotoxicity against tumors. In order to dissect cell surface events important in the cytolytic mechanism, monoclonal antibodies (MABs) against killer cell surfaces have been screened for the ability to block cell-mediated cytotoxicity in the absence of complement. One MAB (RH1-38) specifically blocks cytotoxicity mediated by at least three different effector cells, including NK cells, CTLs, and a monocyte-like cell (phorbal myristate acetate-stimulated HL-60). The antibody immunoprecipitates from PMS-stimulated HL-60 a bimolecular complex (195,000 and 125,000 daltons) which is biochemically similar to the LFA-1 antigen, a previously described cell surface antigen found on CTLs. However, RH1-38, unlike previously described anti-LFA-1 antibodies, does not inhibit effector-target binding. In addition, kinetic studies and single cell cytotoxicity assays have demonstrated that RH1-38 blocks a late step in the cytolytic mechanism. Thus, RH1-38 recognizes either a functionally different epitope on the LFA-1 molecule or alternatively a distinct, functionally important cell surface molecule. Using already developed techniques to determine molecular weight, subunit structure, and surface antigen density, the principal investigator proposes to test the hypothesis that differences in molecular structure and/or surface antigen density are related to cytotoxic activity. In addition, using the HL-60 cell line as a source of antigen, the molecule recognized by RH1-38 will be further characterized biochemically. A variety of other, noncytotoxic immunologic functions will be examined with respect to inhibition by this monoclonal antibody, in order to survey its effect on the immune response. As time permits, it is further proposed to: 1) examine molecular structure and antigen density on lymphocytes from select NK-deficient disease states; 2) develop methods to insert the antigen into the surface on noncytotoxic cells using antigen reconstituted into phosphatidyl choline vesicles; and 3) develop methods for exogenous cell-free translation of the mRNA that encodes for the relevant antigen. Characterization of this and other MABs and the functionally important cell surface molecules they recognize is likely to yield complementary information leading to a dissection of cell surface events important in the cytotoxic response. This will lead to a better understanding of host defense against infectious and malignant disease. (CS)