Charaterization of the Expression and Ligands of KIR3DS1

KIR3DS1被认为是一种NK细胞活化受体。该基因有许多（>40）个抑制等位基因，被称为KIR3DL1。各种KIR3DL1亚型已被证明与具有Bw4公共表位的hla - 1蛋白直接相互作用。尽管KIR3DS1与KIR3DL1很相似，并且在HIV疾病中也有明确的作用，但直到最近才发现KIR3DS1在NK细胞上表达，并且没有描述过配体。为了了解KIR3DS1配体的结合，我们开发了一个KIR3DS1结合的报告系统。该系统使用KIR3DS1融合到T细胞受体zeta信号链。此外，我们还建立了表达HLA Bw4 （B5701）的细胞系。这些细胞系被慢病毒载体感染，并与报告细胞系结合。到目前为止，慢病毒感染并没有导致KIR3DS1报告系统的激活。此外，我们在将这些Bw4表达细胞与报告细胞结合之前，对它们进行了应激诱导。我们还发现了KIR3DS1中不存在的关键残基。通过诱变，我们已经证明KIR3DS1的W138在KIR3DS1对HLA-Bw4的识别缺失中起关键作用。KIR3DL1中发现的W138向G的逆转赋予Bw4结合而不影响受体的表达或抗体识别。

KIR3DS1 is presumed to be an NK cell activation receptor. The gene has many (>40) inhibitory alleles, known as KIR3DL1. Various KIR3DL1 subtypes have been shown to interact directly with HLA-I proteins with the Bw4 public epitope. Regardless of its similarity to KIR3DL1, and its established role in HIV disease, KIR3DS1 has only recently been shown to be expressed on NK cells and no ligand has been described. Toward an understanding of KIR3DS1 ligand binding we developed a reporter system for the engagement of KIR3DS1. The system uses KIR3DS1 fused to the T cell receptor zeta signaling chain. In addition, we have established HLA Bw4 (B5701) expressing cell lines. These cell lines are infected with lentiviral vectors and combined with the reporter line. Thus far, lentiviral infection does not result in the activation of the KIR3DS1 reporter system. In addition, we have induced stress in these Bw4 expressing cells before combining them with the reporter cells. We also have identified key residues of KIR3DS1 that do not exist in KIR3DL1. Through mutagensis we have shown that W138 of KIR3DS1 is critically involved in the lack of recognition of HLA-Bw4 by KIR3DS1. Reversion of W138 to G found in KIR3DL1 confers Bw4 binding without affecting the expression or antibody recognition of the receptor.