Makrigiannis A P, Etzler J, Winkler-Pickett R, Mason A, Ortaldo J R, Anderson S K
Laboratory of Experimental Immunology, Division of Basic Sciences, and lntramural Research Support Program, National Cancer Institute-FCRDC, Frederick, Maryland 21702-1201, USA.
J Leukoc Biol. 2000 Nov;68(5):765-71.
Previous studies have indicated that NK cells from different strains of inbred mice may express distinct Ly49 repertoires. Screening of NK cells from the CBA/J mouse for inhibitory and activating Ly49s revealed a novel DAP12-associated receptor that was immunoprecipitated with the Ly49G-specific mAb 4D11. Degenerate primers were designed to amplify and clone Ly49 cDNAs from CBA/J NK cells. A novel activating Ly49 cDNA was identified, which bears strong homology to the partially sequenced Ly49l gene found in C57BL/6 mice. Transfection of Ly49l into a DAP12+ cell line and subsequent immunoprecipitation experiments showed that Ly49L is likely the activating Ly49 detected by the 4DD11 antibody in CBA/J NK cells. Antibody-mediated cross-linking of Ly49L induced DAP12 phosphorylation, providing evidence that Ly49L is a functional activating receptor. Comparison of the extracellular domains of Ly49 family members indicates that all known activating members have an inhibitory counterpart with a highly related extracellular region.
先前的研究表明，来自不同近交系小鼠品系的自然杀伤（NK）细胞可能表达不同的Ly49受体库。对CBA/J小鼠的NK细胞进行抑制性和激活性Ly49筛选时，发现了一种新的与DAP12相关的受体，该受体可被Ly49G特异性单克隆抗体4D11免疫沉淀。设计简并引物以扩增和克隆CBA/J NK细胞中的Ly49 cDNA。鉴定出一种新的激活性Ly49 cDNA，它与在C57BL/6小鼠中发现的部分测序的Ly49l基因具有高度同源性。将Ly49l转染到DAP12阳性细胞系中并随后进行免疫沉淀实验表明，Ly49L可能是4DD11抗体在CBA/J NK细胞中检测到的激活性Ly49。抗体介导的Ly49L交联诱导DAP12磷酸化，这证明Ly49L是一种功能性激活性受体。Ly49家族成员细胞外结构域的比较表明，所有已知的激活性成员都有一个细胞外区域高度相关的抑制性对应物。
