Kallikrein-related peptidases protein expression in lymphoid tissues suggests potential implications in immune response: KLK protein expression in lymphoid tissues

Panagiota S. Filippou, Annie H Ren, Antoninus Soosaipillai, Roaa Safar, Ioannis Prassas, Eleftherios P Diamandis, James R Conner

Research output: Contribution to journalArticle


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.

Original languageEnglish
Pages (from-to)41-47
Number of pages7
JournalClinical Biochemistry
Early online date2 Jan 2020
Publication statusPublished - 1 Mar 2020


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Copyright © 2020 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

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