Lahoud Mireille H, Proietto Anna I, Ahmet Fatma, Kitsoulis Susie, Eidsmo Liv, Wu Li, Sathe Priyanka, Pietersz Suzanne, Chang Hsuen-Wen, Walker Ian D, Maraskovsky Eugene, Braley Hal, Lew Andrew M, Wright Mark D, Heath William R, Shortman Ken, Caminschi Irina
The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
J Immunol. 2009 Jun 15;182(12):7587-94. doi: 10.4049/jimmunol.0900464.
We have cloned the mouse and human C-type lectin Clec12A, expressed both, and produced mAb recognizing both. Mouse Clec12A is highly expressed on splenic CD8(+) dendritic cells (DC) and plasmacytoid DC. A proportion of CD8(-)DC also expresses lower levels of Clec12A, as do monocytes, macrophages, and B cells. Human CLEC12A, like the mouse counterpart, is expressed on blood monocytes and DC, including pDC and BDCA-3(+)DC, the proposed equivalent of mouse CD8(+)DC. To determine whether Ag targeted to Clec12A could induce immune responses, mice were injected with a rat mAb recognizing Clec12A, or a control rat mAb, then production of anti-rat Ig was measured. Anti-Clec12A mAb alone produced only moderate responses, but these were amplified by coinjecting only small amounts of LPS as a DC activation agent. Furthermore, when OVA was conjugated to anti-Clec12A mAb, OVA-specific T cells were induced to proliferate. This Ag presentation to naive T cells was due to targeting conventional DC, because their ablation eliminated T cell activation. The potent Ab responses induced using microgram amounts of anti-Clec12A and minimal amounts of adjuvant demonstrate that this molecule can be used as an Ag-delivery target to enhance Ab responses to vaccines.
我们克隆了小鼠和人类的C型凝集素Clec12A，对二者进行了表达，并制备了能识别二者的单克隆抗体。小鼠Clec12A在脾脏CD8(+)树突状细胞（DC）和浆细胞样DC上高表达。一部分CD8(-)DC也表达较低水平的Clec12A，单核细胞、巨噬细胞和B细胞也如此。人类CLEC12A与小鼠对应物一样，在血液单核细胞和DC上表达，包括浆细胞样DC和BDCA-3(+)DC，后者被认为等同于小鼠CD8(+)DC。为了确定靶向Clec12A的抗原是否能诱导免疫反应，给小鼠注射识别Clec12A的大鼠单克隆抗体或对照大鼠单克隆抗体，然后检测抗大鼠Ig的产生。单独的抗Clec12A单克隆抗体仅产生适度反应，但通过仅共注射少量LPS作为DC激活剂可使其增强。此外，当OVA与抗Clec12A单克隆抗体偶联时，可诱导OVA特异性T细胞增殖。这种向幼稚T细胞的抗原呈递是由于靶向传统DC，因为去除它们会消除T细胞激活。使用微克量的抗Clec12A和极少量佐剂诱导的强效抗体反应表明，该分子可作为抗原递送靶点以增强对疫苗的抗体反应。
