Characterization of human fibroleukin, a fibrinogen-like protein secreted by T lymphocytes.
Characterization of human fibroleukin, a fibrinogen-like protein secreted by T lymphocytes.
复制标题
DOI：
10.4049/jimmunol.161.1.138
复制
发表时间：
1998-07
影响因子：
4.4
通讯作者：
S. Marazzi;S. Blum;R. Hartmann;D. Gundersen;M. Schreyer;S. Argraves;V. Fliedner;R. Pytela;
中科院分区：
文献类型：
--
作者：
S. Marazzi;S. Blum;R. Hartmann;D. Gundersen;M. Schreyer;S. Argraves;V. Fliedner;R. Pytela;
我们最近克隆了鼠pT 49 cDNA（hpT 49 h）的人类同源物，该cDNA是编码与纤维蛋白原的β-和γ-链同源的蛋白质的转录物。在这里，我们报告的hpT 49 h基因产物的识别使用单克隆抗体产生的肽对应于推导的蛋白质和重组蛋白片段在大肠杆菌中表达的羧基末端。在用全长hpT 49 h cDNA瞬时转染的293 T细胞和新鲜分离的PBMC的培养上清液中，mAb 23 A6、7 B12和3F 4在还原SDS-PAGE中特异性识别70 kDa的蛋白。在非还原条件下，材料迁移的分子量为250至300 kDa，表明70 kDa蛋白质形成二硫键复合物。由于它与纤维蛋白原同源，我们称这种蛋白质为纤维白细胞介素。纤维白细胞介素在体外由新鲜分离的CD 4+和CD 8 + T淋巴细胞自发分泌。RT-PCR分析显示记忆T淋巴细胞（CD 3 +/CD 45 R 0+）较初始T淋巴细胞（CD 3 +/CD 45 RA+）优先表达纤维白细胞介素mRNA。PBMC产生的纤维白细胞介素在培养中迅速丧失。生产可以部分维持在IFN-γ的存在下，而T淋巴细胞活化没有影响。为了证明体内纤维白细胞介素的产生，我们通过免疫组织学分析了结肠粘膜。纤维白细胞介素染色检测到的T淋巴细胞丰富的粘膜固有层上部的细胞外基质。虽然纤维白细胞介素的确切功能仍有待确定，但这些数据表明，纤维白细胞介素可能在粘膜部位的生理淋巴细胞功能中发挥作用。
We have recently cloned the human homologue of the murine pT49 cDNA (hpT49h), a transcript encoding a protein homologous to the beta- and gamma-chains of fibrinogen. Here, we report the identification of the hpT49h gene product using mAbs generated against a peptide corresponding to the carboxyl-terminal end of the deduced protein and a recombinant protein fragment expressed in Escherichia coli. mAbs 23A6, 7B12, and 3F4 specifically recognized a protein of 70 kDa in reducing SDS-PAGE in the culture supernatant of 293T cells transiently transfected with the full length hpT49h cDNA and freshly isolated PBMC. Under nonreducing conditions, the material migrated with a molecular mass of 250 to 300 kDa, indicating that the 70-kDa protein forms a disulfide bonded complex. Because of its homology with fibrinogen, we have termed this protein fibroleukin. Fibroleukin is spontaneously secreted in vitro by freshly isolated CD4+ and CD8+ T lymphocytes. RT-PCR analysis revealed preferential expression of fibroleukin mRNA in memory T lymphocytes (CD3+/CD45R0+) compared with naive T lymphocytes (CD3+/CD45RA+). Fibroleukin production by PBMC was rapidly lost in culture. Production could be partially maintained in the presence of IFN-gamma, while T lymphocyte activation had no effect. To demonstrate fibroleukin production in vivo, we analyzed colon mucosa by immunohistology. Fibroleukin staining was detected in the extracellular matrix of the T lymphocyte-rich upper portion of the lamina propria mucosa. While the exact function of fibroleukin remains to be defined, these data suggest that fibroleukin may play a role in physiologic lymphocyte functions at mucosal sites.