美国PeproTech公司是全球最大的重组细胞因子和蛋白生产商之一，始终致力于为生命科学研究开发重组蛋白及相关产品，如今已成为能提供多种高质量细胞因子和重组蛋白，相应的单克隆、多克隆和生物素标记抗体，以及ELISA试剂盒的世界领导者。PeproTech.的产品涵盖免疫调节蛋白、白介素、集落刺激因子、生长因子、无动物成分的重组蛋白、化学趋化因子、干扰素、脂联素、成纤维生长因子、转化生长因子、肿瘤坏死因子、神经营养素和防御素等诸多生命科学研究领域中重要的生物活性分子。PeproTech公司的产品种类、规格齐全，更新速度快，且价格适中，已广为中国的科研工作者所使用。

为跟踪当今科研发展、满足日益增长的需求，PeproTech公司追求不断创新和与时俱进。PeproTech公司2016年5月推出6种新产品，分别是：

1. 重组人Mesothelin
产品描述：Originally identified as a differentiation antigen of mesotheliomas, ovarian cystadenocarcinomas, and pancreatic adenocarcinomas, mesothelin is a glycosylphosphatidylinositol (GPI)-anchored, cell-surface glycoprotein predominantly secreted by cells of the mesothelium. Although mesothelin is expressed at restricted levels by normal mesothelial cells of the pleural, pericardial, and peritoneal membranes, aberrant expression has been documented in the aforementioned cancers, as well as in endometrioid uterine adenocarcinomas and squamous cell carcinomas of the esophagus, stomach, lung, and cervix. Proteolytic cleavage of mesothelin yields a soluble, polypeptide fragment-designated megakaryocyte-potentiating factor (MPF) based on its ability to stimulate megakaryocyte colony-forming activity of murine IL-3 in murine bone marrow cell cultures. Originally isolated from the HPC-Y5 pancreatic cell line, MPF has been suggested to play a role in the proliferation and differentiation of megakaryoctyes, and the regulation of resultant platelet production. While the biological functions of both mesothelin and MPF remain speculative, high levels of expression in cancerous tissues, compared to limited distribution in normal tissues, strongly suggests their involvement in tumorigenesis. Both have been demonstrated to promote tumor cell proliferation, migration, anchorage-independent growth, and tumor progression, demonstrating their involvement in heterotypic cell adhesion and the metastatic spread of cancer. PeproTech’s CHO cell-derived Recombinant Human Mesothelin is a glycoprotein containing 327 amino acid residues, and has a calculated molecular weight of approximately 36.4 kDa. As a result of glycosylation, Recombinant Human Mesothelin migrates with an apparent molecular mass of approximately 40-45 kDa by SDS-PAGE gel, under reducing and non-reducing conditions.

2. 重组人sIL-4 Receptor α

产品描述：IL-4 can signal through type I and type II receptor complexes, which share a common gamma chain (γc). The type I receptor contains, in addition to the γc, an IL-4Rα subunit, whereas the type II receptor contains the IL-13Rα. The secreted extracellular domain of IL-4Rα, called sIL-4Rα, binds IL-4 and antagonizes its activity. It plays an important role in regulating the differentiation of naïve CD4+ T cells and class switching to IgG1 and IgE. PeproTech'sCHO cell-derived Recombinant Human sIL-4 Receptor α is a 23.9 kDa glycoprotein corresponding to 209 amino acid residues of the extracellular domain of IL-4Rα. As a result of glycosylation, Recombinant Human sIL-4 Receptor α migrates with an apparent molecular mass of approximately 50-65 kDa by SDS-PAGE gel, under reducing conditions.

3. 重组人sIL-6 Receptor α

产品描述：IL-6 mediates its biological effects through the type I IL-6 receptor system that consists of two chains, IL-6Rα and gp130. While the IL-6Rα chain is the binding component specific to IL-6, the gp130 chain only transmits signals of IL-6 when bound to IL-6Rα. The gp130 can also transmit signals from LIF, OSM, CNTF, IL-11 and CT-1 in conjunction with other receptor subunits. The low-affinity binding site for IL-6 is composed of IL-6Rα alone. IL-6Rα is expressed in a wide range of cells, including T cells, fibroblasts and macrophages. Soluble IL-6Rα, which consists of only the extracellular domain of the IL-6Rα chain, acts as an agonist of IL-6 activity at low concentrations. PeproTech's CHO cell-derived Recombinant Human sIL-6 Receptor α is a 37.9 kDa glycoprotein corresponding to 339 amino acid residues of the extracellular domain of IL-6Rα. As a result of glycosylation, Recombinant Human sIL-6 Receptor α migrates with an apparent molecular mass of approximately 57-70 kDa by SDS-PAGE gel, under reducing conditions.

4. 重组人Leptin Receptor

产品描述：Encoded for, along with leptin, by the obese (ob)gene, leptin receptor is a single-transmembrane-domain protein of the Type I, or Class I, Cytokine Receptor Family. The full length isoform, OB-Rb, is highly expressed in hypothalamic neurons, T-cells, and the vascular endometrium, and is thought to be the only isoform capable of transducing intracellular signals. Isoform OB-Ra, which is widely distributed at varying levels of expression, demonstrates weak signal activity and has been implicated in the active transport of leptin across the blood-brain barrier. Through ligand-binding with leptin receptor and the subsequent JAK2/STAT3 signaling cascade, the adipose-derived cytokine leptin functions to suppress appetite and increase thermogenesis. Leptin and leptin receptor have also, more recently, been implicated in the regulation or immune function, reproduction, glucose homeostasis, bone metabolism, wound healing, hematopoiesis, and angiogenesis. Mutations of the ob gene, which can result in leptin resistance and the down-regulation of ligand and/or receptor expression, have been connected to obesity and hypothalamic pituitary function in various in vivo models, including human, mouse, and rat. PeproTech’s Recombinant Human Leptin Receptor is a single, glycosylated polypeptide chain of 818 amino acid residues, corresponding to the human OB-Re isoform, and has a calculated molecular weight of approximately 93.5 kDa. As a result of glycosylation, Recombinant Human Leptin Receptor migrates with an apparent molecular mass of approximately 130-150 kDa by SDS-PAGE gel, under reducing and non-reducing conditions.


5. 重组人CTLA-4 Fc

产品描述：CTLA-4 and CD28 are receptors of the immunoglobulin superfamily that are expressed, along with the transmembrane glycoproteins B7-1 and B7-2, by antigen-presenting cells, and with these ligands constitute crucial co-stimulatory pathways for T and B cell regulatory responses. It is through engagement with CD28 and CTLA-4 that the B7 family ligands B7-1 and B7-2 play principal roles in immunity by activating immune response and maintaining immune tolerance. Co-stimulatory signals generated by B7-1 and B7-2 interactions with CD28 serve to stimulate T cell activation and prevent anergy through the amplification of T cell receptor (TCR) signaling. In contrast, interactions of the ligands with CTLA-4 serves to maintain T cell homeostasis and self-tolerance through the disruption of stimulatory signaling from B7 isoform-bound CD28 complexes, and by inducing powerful inhibitory signals in T cells. CTLA-4, like B7-1, is only poorly expressed on resting dendritic cells; therefore, up-regulation of their interaction and resultant amplification and regulation of T cell activity at peripheral inflammation sites is considerably delayed upon immune activation. Conversely, B7-2 and CD28 are constitutively expressed by resting hematopoietic and T cells, respectively, and as a result are able to rapidly induce up-regulation upon immune activation, making them critical to the early co-stimulatory signaling of immune response. Unlike B7-1 and B7-2, the ligands PD-L1 (or B7-H1) and B7-H2, which also belong to the B7 family, have not been shown to influence immunity through interaction with CTLA-4. B7-H2 has been shown to have restricted interaction with CD28. The difference in expression of B7-1, B7-2 and B7-H2 may enable temporally and spatially-specific regulation of T cell response through non-competitive CD28 interaction. PeproTech’s CHO cell-derived Recombinant Human CTLA-4 Fc is a glycosylated, disulfide-linked homodimer of 714 amino acid residues whose monomer consists of the 124-amino-acid length extracellular portion of CTLA-4 fused to the 231-amino-acid length Fc portion of human IgG1 by two glycines. The calculated molecular weight of Recombinant Human CTLA-4 Fc dimer is 78.7 kDa; however, due to glycosylation, the monomer and dimer migrate at apparent molecular weights of approximately 45–50 kDa and 80–90 kDa by SDS-PAGE analysis under reducing conditions.

6. 重组人sCD28 Fc

产品描述：CTLA-4 and CD28 are receptors of the immunoglobulin superfamily that are expressed, along with the transmembrane glycoproteins B7-1 and B7-2, by antigen-presenting cells, and with these ligands constitute crucial co-stimulatory pathways for T and B cell regulatory responses. It is through engagement with CD28 and CTLA-4 that the B7 family ligands B7-1 and B7-2 play principal roles in immunity by activating immune response and maintaining immune tolerance. Co-stimulatory signals generated by B7-1 and B7-2 interactions with CD28 serve to stimulate T cell activation and prevent anergy through the amplification of T cell receptor (TCR) signaling. In contrast, interactions of the ligands with CTLA-4 serves to maintain T cell homeostasis and self-tolerance through the disruption of stimulatory signaling from B7 isoform-bound CD28 complexes, and by inducing powerful inhibitory signals in T cells. CTLA-4, like B7-1, is only poorly expressed on resting dendritic cells; therefore, up-regulation of their interaction and resultant amplification and regulation of T cell activity at peripheral inflammation sites is considerably delayed upon immune activation. Conversely, B7-2 and CD28 are constitutively expressed by resting hematopoietic and T cells, respectively, and as a result are able to rapidly induce up-regulation upon immune activation, making them critical to the early co-stimulatory signaling of immune response. Unlike B7-1 and B7-2, the ligands PD-L1 (or B7-H1) and B7-H2, which also belong to the B7 family, have not been shown to influence immunity through interaction with CTLA-4. B7-H2 has been shown to have restricted interaction with CD28. The difference in expression of B7-1, B7-2 and B7-H2 may enable temporally and spatially-specific regulation of T cell response through non-competitive CD28 interaction. PeproTech’s CHO cell-derived Recombinant Human sCD28 Fc is a glycosylated, disulfide-linked homodimer of 734 amino acid residues whose monomer consists of the 134-amino-acid length extracellular portion of CD28 fused to the 231-amino-acid length Fc portion of human IgG1 by two glycines. The calculated molecular weight of Recombinant Human sCD28 Fc dimer is 82.4 kDa; however, due to glycosylation, the monomer and dimer migrate at apparent molecular weights of approximately 60-70 kDa and 150–160 kDa by SDS-PAGE analysis under reducing conditions.