OBJECTIVES Kallikrein-related peptidases (KLKs) are a subgroup of 15 secreted chymotrypsin- and trypsin-like serine proteases that have been reported to possess novel functions in innate immunity and inflammation. Since the potential role of KLKs in immunity has not been studied in detail at the protein level, we examined the expression pattern of 12 members of the KLK family in immune-related tissues. DESIGN & METHODS Protein expression in tissue extracts was evaluated using immunoassays (ELISA). Immunohistochemistry (IHC) was performed on representative sections of tonsil and lymph nodes to determine the cellular localization of the KLK family members. RESULTS ELISA profiling of KLK3-KLK15 (except KLK12) revealed higher protein levels in the tonsil, compared to the lymph nodes and spleen. Relatively high protein levels in the tonsil were observed for KLK7, KLK9, KLK10 and KLK13. Expression of these KLKs was significantly lower in lymph nodes and spleen. IHC analysis in tonsil unveiled that KLK9 and KLK10 were differentially expressed in lymphoid cells. KLK9 was strongly expressed in the germinal center of lymphoid follicles where activated B-cells reside, whereas KLK10 was expressed in the follicular dendritic cells (FDCs) that are vital for maintaining the cycle of B cell maturation. CONCLUSION Overall, our study revealed the possible implications of KLK expression and regulation in the immune cells of lymphoid tissues.

中文翻译：

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淋巴组织中激肽释放酶相关的肽酶蛋白表达暗示了免疫反应的潜在意义。

目的激肽释放酶相关肽酶（KLKs）是15种分泌的胰凝乳蛋白酶和胰蛋白酶样丝氨酸蛋白酶的一个亚组，据报道它们在先天免疫和炎症中具有新功能。由于尚未在蛋白质水平上详细研究KLKs在免疫中的潜在作用，因此我们检查了KLK家族12个成员在免疫相关组织中的表达模式。设计与方法使用免疫测定（ELISA）评估组织提取物中的蛋白质表达。对扁桃体和淋巴结的代表性切片进行免疫组织化学（IHC），以确定KLK家族成员的细胞定位。结果与淋巴结和脾脏相比，KLK3-KLK15（除了KLK12）的ELISA分析显示扁桃体中的蛋白质水平更高。对于KLK7，KLK9，KLK10和KLK13，在扁桃体中观察到相对较高的蛋白质水平。这些KLK的表达在淋巴结和脾脏中显着降低。扁桃体中的IHC分析表明，KLK9和KLK10在淋巴样细胞中差异表达。KLK9在活化的B细胞所在的淋巴滤泡的生发中心强烈表达，而KLK10在维持B细胞成熟周期至关重要的滤泡树突状细胞（FDC）中表达。结论总的来说，我们的研究揭示了淋巴组织免疫细胞中KLK表达和调控的可能含义。扁桃体中的IHC分析表明，KLK9和KLK10在淋巴样细胞中差异表达。KLK9在活化的B细胞所在的淋巴滤泡的生发中心强烈表达，而KLK10在维持B细胞成熟周期至关重要的滤泡树突状细胞（FDC）中表达。结论总的来说，我们的研究揭示了淋巴组织免疫细胞中KLK表达和调控的可能含义。扁桃体中的IHC分析表明，KLK9和KLK10在淋巴样细胞中差异表达。KLK9在活化的B细胞所在的淋巴滤泡的生发中心强烈表达，而KLK10在维持B细胞成熟周期至关重要的滤泡树突状细胞（FDC）中表达。结论总的来说，我们的研究揭示了淋巴组织免疫细胞中KLK表达和调控的可能含义。