Importance of CD2-LFA-3 interaction in differentiation and function of T and NK cells.

1. 我们克隆并测序了小鼠CD2 cDNA，发现其细胞质区在人和小鼠CD2.2之间具有高度保守的初级结构。我们通过筛选它们对转染小鼠CD2 cdna的大鼠成纤维细胞的反应性，建立了5种大鼠抗小鼠CD2单克隆抗体。通过FACS和Northern blot分析，我们发现大多数B细胞以及T和NK细胞在小鼠中表达CD2，这与人类不同。小鼠B细胞在B前期出现CD2。我们证明了小鼠CD2的粘附功能和我们的单克隆抗体对它的抑制作用。通过用亲和纯化的小鼠CD2分子免疫，我们建立了与大鼠单抗识别的表位不同的仓鼠单抗。大鼠和仓鼠单抗的某些组合诱导小鼠T细胞激活和增殖，表明小鼠CD2与人类CD2.6一样，是T细胞激活的另一条途径。转染CD2后，CD2^- T细胞杂交瘤对低浓度Ag有40 ~ 10倍的反应。在引入缺乏大部分细胞质区域的突变CD2后，没有观察到这种Ag反应的增强，这表明CD2介导的信号转导在调节T细胞Ag反应中的重要性。将CD2引入CD2^- NK细胞系诱导对某些靶细胞的结合和细胞毒性。相比之下，细胞质缺失突变体导致了类似的结合，但细胞毒性大大降低，这表明CD2在调节NK细胞结合和细胞毒性方面发挥了重要作用。CD2在小鼠胎儿胸腺发育过程中很早就出现在胸腺细胞上。然而，到目前为止，还没有观察到将抗cd2单克隆抗体添加到胎儿胸腺器官培养物中对T细胞发育的影响。

1. We cloned and sequenced the murine CD2 cDNA and noted a highly conserved primary structure of its cytoplasmic region between human and mouse CD2.2. We established five rat anti-mouse CD2 mAbs by screening their reactivities to rat fibroblasts transfected with the mouse CD2 cDNA.3. By FACS and Northern blot analyses, we revealed that most B cells as well as T and NK cells express CD2 in mice unlike in humans. CD2 appeared on murine B cells at the pre-B stage.4. We demonstrated the adhesion function of mouse CD2 and inhibitory effects of our mAbs on it.5. We established additional hamster mabs reactive with distinct epitopes from those recognized by rat mabs by immunizing with affinity-purified mouse CD2 molecules. Certain combinations of the rat and hamster mabs induced mouse T cell activation and proliferation, indicating that mouse CD2 constitutes an alternative pathway of T cell activation like human CD2.6. A CD2^- T cell hybridoma could respond to 40 to 10-fold lower concentrations of the Ag after CD2 introduction by cDNA transfection. Such an augmentation of Ag response was not observed after introduction of a mutant CD2 lacking most of cytoplasmic region, indicating an importance of the CD2-mediated signal transduction in regulating T cell Ag response.7. Introduction of CD2 into a CD2^- NK cell line induced binding and cytotoxicity against certain target cells. In contrast, that of cytoplasmic deletion mutant led to a comparable binding but a greatly reduced cytotoxicity, demonstrating an important role of CD2 in regulating NK cell binding and cytotoxicity.8. CD2 appeared on murine thymocytes very early during fetal thymus ontogeny. However, so far no effect of anti-CD2 mAbs on T cell development has been observed when added into fetal thymus organ cultures.