Transglutaminase 2 on the surface of dendritic cells is proposed to be involved in dendritic cell–T cell interaction

• Published in: Cellular immunology 2014-05, Vol.289 (1-2), p.55-62
• Main Authors: Kim, Jin-Hee, Jeong, Eui Man, Jeong, Young-Joo, Lee, Wang Jae, Kang, Jae Seung, Kim, In-Gyu, Hwang, Young-il
• Format: Article
• Language: English
• Subjects: Animals; Antibodies - immunology; Antigens, CD - biosynthesis; Antigens, Differentiation, T-Lymphocyte - biosynthesis; B7-1 Antigen - biosynthesis; B7-2 Antigen - biosynthesis; Bone Marrow Cells - cytology; Bone Marrow Cells - immunology; CD40 Antigens - biosynthesis; Cell Communication - immunology; Cell Proliferation; Cells, Cultured; Coculture Techniques; DC–T cell interaction; Dendritic cell; Dendritic Cells - enzymology; Dendritic Cells - immunology; GTP-Binding Proteins - genetics; GTP-Binding Proteins - metabolism; Histocompatibility Antigens Class II - biosynthesis; Interferon-gamma - secretion; Interleukin-10 - secretion; Interleukin-12 - secretion; Interleukin-2 Receptor alpha Subunit - biosynthesis; Lectins, C-Type - biosynthesis; Lymphocyte Activation - immunology; Lymphocyte Culture Test, Mixed; Male; Mice; Mice, Knockout; T cell activation; T-Lymphocytes - immunology; Transglutaminase 2; Transglutaminases - genetics; Transglutaminases - metabolism
• ISSN: 0008-8749; 1090-2163
• DOI: 10.1016/j.cellimm.2014.03.008

•TG2 expression on DCs was identified.•T cells co-cultured with TG2−/− DCs showed reduced frequency of activation marker expression.•TG2 was found at the DC–T cell interface.•These results suggest the possibility of the involvement of surface TG2 in DC–T cell interaction. Transglutaminase 2 (TG2) is a ubiquitous enzyme involved in diverse biological processes. Recently, its function in adaptive immune responses has begun to emerge. Its presence and functions in B cells and T cells, for example, have been reported. However, those in dendritic cells (DCs), the principal antigen-presenting cells, are as yet unexplored in murine system. In this study, we first investigated the expression of TG2 in murine bone marrow-derived DCs, and then compared the functioning of these cells in the presence or absence of this enzyme using wild-type (WT) and TG2−/− mice. We found that the WT DCs expressed TG2 both in the cytoplasm and on the cell surface, both of which were elevated after LPS stimulation. Unexpectedly, between WT and TG2−/− DCs, there were no remarkable differences in cytokine secretion, IL-10 and IL-12, and neither in the expression of surface molecules CD80, CD86, and MHC II, excepting a moderate decrease of CD40 expression on the TG2−/− DCs. However, when T cells were stimulated with TG2−/− DCs, they showed decreased levels of proliferation, CD69 and CD25 expression, and IFN-γ secretion. The addition of anti-TG2 antibody to the WT DC–T cell co-culture resulted in decreased T cell activation. By immunofluorescence staining, TG2 was observed at DC–T cell interface (contact point). Taken together, we propose that TG2 on the surface of DCs modulates the DC–T cell interaction.