Moretta A, Pantaleo G, Lopez-Botet M, Moretta L
J Exp Med. 1985 Sep 1;162(3):823-38. doi: 10.1084/jem.162.3.823.
Prior studies indicate that the 9.3 monoclonal antibody (mAb) which defines a 44 kD T lineage-specific glycoprotein (T44) enhances the proliferative response of peripheral blood T lymphocytes to phytohemagglutinin (PHA) or allogeneic cells. The T44 molecule was expressed in both resting and activated T lymphocytes and in a subset of thymocytes, as assessed by indirect immunofluorescence and flow cytofluorometry. In view of the potential importance of T44 in T cell activation, we investigated the ability of the 9.3 (anti-T44) antibody to stimulate peripheral blood T lymphocytes under culture conditions giving optimal proliferative responses to anti-T3 mAb. Like UCHT1 (anti-T3) mAb, the 9.3 (anti-T44 mAb) promoted strong proliferative responses of purified T cells, provided that adherent cells were added to the culture. Maximal proliferation in response to 9.3 antibody was consistently detected at day 5 (at day 3 with anti-T3 or PHA). Moreover, triggering of T lymphocytes with 9.3 antibody (in the presence of adherent cells) resulted in strong IL-2 production that peaked at 48 h. Analysis of the physical and functional relationship between the T44 molecule and other molecules involved in T cell activation, including the clonotypically restricted Ti and the monomorphic T3 or T11 molecules, was carried out on a mutagenized jurkat T leukemia cell line. This mutant, termed JA3 (surface phenotype: T11+, T3+, 3A1+, T4-, T8-, DR-, Tac-, 4F2+, T44+) produced large amounts of IL-2 upon stimulation with PHA, anti-T3, or anticlonotypic mAb in conjunction with phorbol myristate acetate (or adherent cells). The molecules precipitated by anti-T44 mAb from 125I-labeled JA3 cells appeared as a diffuse band of Mr 40-45,000 under reducing conditions; under nonreducing conditions, a prominent band of Mr 80-85,000 was observed, while the Mr 40-45,000 band was greatly reduced. Thus, T44 molecules in both reducing and nonreducing conditions had relative molecular weights similar to that of molecules carrying clonotypic (Ti) determinants. In addition, like anti-Ti or anti-T3 mAb, anti-T44 antibody induced JA3 cells to produce large amounts of IL-2 in the presence of phorbol myristate acetate. Other similarities between T44 and molecules carrying clonotypic structures included the susceptibility to antibody-induced modulation and the late reexpression (72 h) at the cell surface after modulation. Taken together, these experiments suggest that anti-T44 mAb might recognize a monomorphic determinant of the T cell receptor molecule or be physically or functionally linked to the T3-Ti complex.(ABSTRACT TRUNCATED AT 400 WORDS)
先前的研究表明，定义一种44kD T细胞系特异性糖蛋白（T44）的9.3单克隆抗体（mAb）可增强外周血T淋巴细胞对植物血凝素（PHA）或同种异体细胞的增殖反应。通过间接免疫荧光和流式细胞荧光测定法评估，T44分子在静息和活化的T淋巴细胞以及一部分胸腺细胞中均有表达。鉴于T44在T细胞活化中的潜在重要性，我们研究了9.3（抗T44）抗体在能使抗T3 mAb产生最佳增殖反应的培养条件下刺激外周血T淋巴细胞的能力。与UCHT1（抗T3）mAb一样，9.3（抗T44 mAb）能促进纯化T细胞的强烈增殖反应，前提是向培养物中添加贴壁细胞。在第5天始终能检测到对9.3抗体的最大增殖反应（抗T3或PHA则在第3天）。此外，用9.3抗体（在有贴壁细胞存在的情况下）触发T淋巴细胞会导致强烈的IL-2产生，在48小时达到峰值。在一个诱变的Jurkat T白血病细胞系上，对T44分子与参与T细胞活化的其他分子之间的物理和功能关系进行了分析，这些分子包括克隆型受限的Ti以及单态性的T3或T11分子。这个突变体称为JA3（表面表型：T11 +、T3 +、3A1 +、T4 -、T8 -、DR -、Tac -、4F2 +、T44 +），在用PHA、抗T3或抗克隆型mAb与佛波醇肉豆蔻酸酯乙酸酯（或贴壁细胞）共同刺激时会产生大量IL-2。在还原条件下，抗T44 mAb从125I标记的JA3细胞中沉淀出的分子呈现为一条Mr 40 - 45,000的弥散带；在非还原条件下，观察到一条突出的Mr 80 - 85,000的带，而Mr 40 - 45,000的带则大大减少。因此，在还原和非还原条件下，T44分子的相对分子量与携带克隆型（Ti）决定簇的分子相似。此外，与抗Ti或抗T3 mAb一样，抗T44抗体在佛波醇肉豆蔻酸酯乙酸酯存在的情况下能诱导JA3细胞产生大量IL-2。T44与携带克隆型结构的分子之间的其他相似之处包括对抗体诱导的调节的敏感性以及调节后在细胞表面的晚期重新表达（72小时）。综上所述，这些实验表明抗T44 mAb可能识别T细胞受体分子的一个单态性决定簇，或者在物理上或功能上与T3 - Ti复合物相关联。（摘要截短于400字）
