Stimulation of Dectin-1 and Dectin-2 during Parenteral Immunization, but Not Mincle, Induces Secretory IgA in Intestinal Mucosa

Hindawi Journal of Immunology Research Volume 2018, Article ID 3835720, 13 pages https://doi.org/10.1155/2018/3835720 Research Article Stimulation of Dectin-1 and Dectin-2 during Parenteral Immunization, but Not Mincle, Induces Secretory IgA in Intestinal Mucosa Alina S. Dzharullaeva, Amir I. Tukhvatulin , Alina S. Erokhova , Alina S. Bandelyuk , Nikita B. Polyakov , Andrey I. Solovyev , Natalia A. Nikitenko , Dmitry V. Shcheblyakov , Boris S. Naroditsky , Denis Y. Logunov , and Alexander L. Gintsburg N. F. Gamaleya National Research Center for Epidemiology and Microbiology, Gamaleya str.18, Moscow 123098, Russia Correspondence should be addressed to Denis Y. Logunov; Received 23 October 2017; Accepted 27 December 2017; Published 14 March 2018 Academic Editor: Manoj K. Mishra Copyright © 2018 Alina S. Dzharullaeva et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Induction of a robust and long-lived mucosal immune response during vaccination is critical to achieve protection against numerous pathogens. However, traditional injected vaccines are generally poor inducers of mucosal immunity. One of the effective strategies to improve vaccine efficacy is incorporation of adjuvant molecules that enhance and polarize adaptive immune reactions. Effects of Syk-coupled lectin receptor agonists as adjuvants to induce mucosal immune reactions during parenteral immunization are not fully studied. We now report that the agonists trehalose-6,6-dibehenate (TDB), curdlan, and furfurman, which stimulate Dectin-1, Dectin-2, and Mincle, respectively, activate transcription factors (NF-κB, NFAT, and AP-1) to various extents in murine RAW 264.7 macrophages, even though similar pathways are activated. The agonists also elicit differential expression of maturation markers in bone marrow-derived dendritic cells, as well as differential cytokine secretion from these cells and from splenic mononuclear cells. In vivo assays also show that agonists of Dectin-1 and Dectin-2, but not Mincle, induce heavy IgA secretion in intestinal mucosa even when delivered parenterally. Strikingly, this effect appears to be formulation-independent. Collectively, the data suggest that adjuvants based on Dectin-1 and Dectin-2 agonists may significantly improve the efficacy of parenteral vaccines by inducing robust local immune reactions in intestinal mucosa. 1. Introduction Vaccination has greatly reduced the burden of infectious diseases, preventing around 2-3 million annual deaths worldwide [1]. However, existing vaccines prevent only approximately 10% of all life-threatening infections. Thus, new vaccines, as well as novel approaches to effectively induce protective immunity, are urgently needed. Most pathogens use epithelial barriers in the respiratory (Mycobacterium tuberculosis [2], adenovirus [3], and coronavirus [4]), gastrointestinal (Salmonella [5], Helicobacter pylori [6], and Escherichia coli [7]), and urogenital tract (Chlamydia [8], human papillomavirus [9], and human immunodeficiency virus [10]) as ports of entry. Accordingly, elements of mucosal immunity, including antigen-specific secretory IgA, T cells, cytokines, and antimicrobial peptides, promote protection against these infections [2, 11]. However, traditional injected vaccines are generally poor inducers of mucosal immunity and are therefore less effective against mucosal infections than mucosal vaccines [12]. Hence, it is important to investigate the induction and maintenance of mucosal immunity in order to generate effective vaccines against multiple pathogens. It is known that pattern recognition receptors (PRRs) play essential role in the formation of immune defense on mucosal surfaces [13]. While the beneficial effect of PRR signaling for mucosal protective immunity has been established, the ability of PRR agonist-based adjuvants to promote local mucosal immune reactions during parenteral vaccination has not been 2 Journal of Immunology Research extensively investigated. Thus, subcutaneous priming followed by airway booster immunization with CAF01, a clinically approved adjuvant, loaded with the C-type lectin (CLR) agonist trehalose-6,6-dibehenate (TDB), was recently demonstrated to induce strong immune reactions in the airway mucosa, including enhanced formation of Th17 cells and abundant IgA secretion [14, 15]. However, mucosal adjuvants based on other CLR agonists remain largely uncharacterized. Hence, we investigated the ability of TDB, curdlan, and furfurman, which stimulate Mincle, Dectin-1, and Dectin-2, respectively, to elicit both mucosal and systemic immune reactions via several transcription factors (NF-κB, NFAT, and AP-1) and cellular pathways (cytokine secretion and maturation of dendritic cells). Head-to-head comparison using reporter cell lines showed that the agonists activate transcription factors to varying extents. In vitro studies showed that TDB and curdlan elicit production of mixed Th1/Th17 cytokines (IFNγ, TNFα, IL-12, IL-6, and IL-23), whereas furfurman predominantly induces production of Th17 cytokines (IL-6, IL-17A, and IL-23). Finally, we demonstrate for the first time that subcutaneous prime-boost immunization with curdlan and furfurman, but not with TDB, boosts IgA production in intestinal mucosa after parenteral immunization. Collectively, these results highlight Dectin-1 and Dectin-2 agonists as potential adjuvants to induce local mucosal immunity during parenteral immunization. with 10% fetal bovine serum (FBS, Thermo Fisher Scientific, USA), 50 U/mL penicillin, 50 μg/mL streptomycin, 2 mM glutamine, and 0.1 M NaHCO3 (all PanEco, Russia) at 37°C with 5% CO2. We used the protocol described in our previous work [16]; namely, experiment cells were seeded at 1 × 105 cells/well in 96-well plates (100 μL/well). The next day, C-type lectin receptor agonists were added to the wells to a final concentration of 20 μg/mL, 4 μg/mL, and 1 μg/mL. Eight hours later, to detect luciferase activity, 100 μL of Bright-Glo Luciferase Assay Buffer containing luciferin substrate (Promega, USA) was added to each well. Luminescence was measured in relative units using a Synergy H4 Hybrid Reader (BioTek, Germany). 2. Materials and Methods 2.5. Dendritic Cell Culture. Bone marrow-derived dendritic cells (BMDCs) from C57BL/6 mice were differentiated from proliferating mouse bone marrow progenitors through induction with 20 ng/mL granulocyte macrophage colonystimulating factor (GM-CSF) (R&D Systems, USA) over 8 days as described [17]. Briefly, mice were euthanized by CO2 overdose. Femurs and tibias were collected in phosphate buffered saline (PBS) solution (Sigma-Aldrich, USA). The muscles were removed with a scalpel. Then, epiphyses were cut off with scissors. The bone marrow was flushed out with 2-3 mL of RPMI medium in a syringe with a 25G needle and resuspended. All bone mar (...truncated)