Zouk H, D'Hennezel E, Du X, Ounissi-Benkalha H, Piccirillo C A, Polychronakos C
Endocrine Genetics Laboratory, McGill University Health Center, Montreal Children's Hospital Research Institute, McGill University, QC, Montreal, Canada; Department of Human Genetics, McGill University, QC, Montreal, Canada.
Clin Exp Immunol. 2014 Mar;175(3):485-97. doi: 10.1111/cei.12240.
The type 1 diabetes-associated 16p13 locus contains the CLEC16A gene. Its preferential immune cell expression suggests involvement in autoimmunity. Given its elevated expression in dendritic and B cells - known professional antigen-presenting cells (APCs) - we hypothesize that C-type lectin domain family 16 member A (CLEC16A) may be involved in T cell co-stimulation and consequent activation and proliferation. We also sought to identify CLEC16A's subcellular localization. The effect of the CLEC16A knock-down (KD) on B cell co-stimulation and activation of T cells was tested in human lymphoblastoid cell lines (LCLs) by co-culture with CD4(+) T cells. T cell activation and proliferation were determined by flow-cytometric analysis of CD69 and CD25 expression and carboxyfluorescein succinimidyl ester (CFSE) dilution, respectively. CLEC16A subcellular localization in K562 cells was examined by immunofluorescence. We show that the CLEC16A KD did not affect the tested indices of lymphoblastoid cell line (LCL) APC capacity. Additionally, the percentage of activated T cells following LCL co-culture was not affected significantly by the CLEC16A KD. T cells co-cultured with KD or control LCLs also exhibited similar cell division profiles. CLEC16A co-localized with an endoplasmic reticulum (ER) marker, suggesting that it may be an ER protein. In conclusion, CLEC16A may not be involved in T cell co-stimulation. Additional studies on CLEC16A, accounting for its ER localization, are needed to uncover its biological role.
1型糖尿病相关的16p13基因座包含CLEC16A基因。其在免疫细胞中的优先表达提示其参与自身免疫。鉴于其在树突状细胞和B细胞（已知的专职抗原呈递细胞）中表达升高，我们推测C型凝集素结构域家族16成员A（CLEC16A）可能参与T细胞共刺激以及随后的激活和增殖。我们还试图确定CLEC16A的亚细胞定位。通过与CD4(+) T细胞共培养，在人淋巴母细胞系（LCLs）中测试了CLEC16A基因敲低（KD）对B细胞共刺激和T细胞激活的影响。分别通过流式细胞术分析CD69和CD25表达以及羧基荧光素琥珀酰亚胺酯（CFSE）稀释来确定T细胞的激活和增殖。通过免疫荧光检查K562细胞中CLEC16A的亚细胞定位。我们发现CLEC16A基因敲低并不影响淋巴母细胞系（LCL）抗原呈递细胞能力的测试指标。此外，CLEC16A基因敲低对LCL共培养后活化T细胞的百分比没有显著影响。与KD或对照LCL共培养的T细胞也表现出相似的细胞分裂模式。CLEC16A与内质网（ER）标志物共定位，提示它可能是一种内质网蛋白。总之，CLEC16A可能不参与T细胞共刺激。需要对CLEC16A进行更多研究，考虑到其内质网定位，以揭示其生物学作用。
