• Biomolecules & Therapeutics
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• v.19 no.1
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• pp.77-83
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• 2011

Sulforaphane is an isothiocyanate found in cruciferous vegetables that has been reported to be an effective cancer preventive agent inducing growth arrest and/or cell death in cancer cells of various organs. This paper reports that sulforaphane exerts immunomodulatory activity on the MHC-restricted antigen presenting function. Sulforaphane efficiently increased the class II-restricted presentation of an exogenous antigen, ovalbumin (OVA), in both dendritic cells (DCs) and peritoneal macrophages in vitro. The class II-restricted OVA presentation-enhancing activity of sulforaphane was also confirmed using mice that had been injected with sulforaphane followed by soluble OVA. On the other hand, sulforaphane did not affect the class I-restricted presentation of exogenous OVA at concentrations that increase the class II-restricted antigen presentation. At a high concentration ($20\;{\mu}M$), sulforaphane inhibited the class I-restricted presentation of exogenous OVA. Sulforaphane did not affect the phagocytic activity of the DCs, and the cell surface expression of total H-$2K^b$, B7-1, B7-2 and CD54 molecules, even though it increased the expression of I-$A^b$ molecules to a barely discernable level. These results show that sulforaphane increases the class II-restricted antigen presenting function preferentially, and might provide a novel insight into the mechanisms of the anti-cancer effects of sulforaphane.

• IMMUNE NETWORK
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• v.6 no.2
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• pp.102-110
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• 2006

Background: Dendritic cells (DC) are professional antigen-presenting cells in the immune system and can induce T cell response against virus infections, microbial pathogens, and tumors. Therefore, immunization using DC loaded with tumor-associated antigens (TAAs) is a powerful method of inducing anti-tumor immunity. For induction of effective anti-tumor immunity, antigens should be efficiently introduced into DC and presented on MHC class I molecules at high levels to activate antigen-specific $CD8^+$ T cells. We have been exploring methods for loading exogenous antigens into APC with high efficiency of Ag presentation. In this study, we tested the effect of the cationic liposome (Lipofectin) for transferring and loading exogenous model antigen (OVA protein) into BM-DC. Methods: Bone marrow-derived DC (EM-DC) were incubated with OVA-Lipofectin complexes and then co-cultured with B3Z cells. B3Z activation, which is expressed as the amount of ${\beta}$-galactosidase induced by TCR stimulation, was determined by an enzymatic assay using ${\beta}$-gal assay system. C57BL/6 mice were immunized with OVA-pulsed DC to monitor the in vivo vaccination effect. After vaccination, mice were inoculated with EG7-OVA tumor cells. Results: BM-DC pulsed with OVA-Lipofectin complexes showed more efficient presentation of OVA-peptide on MHC class I molecules than soluble OVA-pulsed DC. OVA-Lipofectin complexes-pulsed DC pretreated with an inhibitor of MHC class I-mediated antigen presentation, brefeldin A, showed reduced ability in presenting OVA peptide on their surface MHC class I molecules. Finally, immunization of OVA-Lipofectin complexes-pulsed DC protected mice against subsequent tumor challenge. Conclusion: Our data provide evidence that antigen-loading into DC using Lipofectin can promote MHC class I- restricted antigen presentation. Therefore, antigen-loading into DC using Lipofectin can be one of several useful tools for achieving efficient induction of antigen-specific immunity in DC-based immunotherapy.

• IMMUNE NETWORK
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• v.7 no.4
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• pp.197-202
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• 2007

Background: Immunomodulators enhancing MHC-restricted antigen presentation would affect many cellular immune reactions mediated by T cells or T cell products. However, modulation of MHC-restricted antigen presentation has received little attention as a target for therapeutic immunoregulation. Here, we report that lectins isolated from mushroom Fomitella fraxinea enhance MHC-restricted exogenous antigen presentation in professional antigen presenting cells (APCs). Methods: Lectins, termed FFrL, were isolated from the carpophores of Fomitella fraxinea, and its effects on the class I and class II MHC-restricted presentation of exogenous ovalbumin (OVA) were examined in mouse dendritic cells (DCs) and mouse peritoneal macrophages. The effects of FFrL on the expression of total MHC molecules and the phagocytic activity were also examined in mouse DCs. Results: DCs cultured in the presence of FFrL overnight exhibited enhanced capacity in presenting exogenous OVA in association with class I and class II MHC molecules. FFrL increased slightly the total expression levels of both class I (H-$2K^b$) and class II (I-$A^b$) MHC molecules and the phagocytic activity of DCs. Antigen presentation-enhancing activity of FFrL was also observed in macrophages isolated from mouse peritoneum. Conclusion: Lectins isolated from the carpophores of Fomitella fraxinea increase MHC-restricted exogenous antigen presentation by enhancing intracellular processing events of phagocytosed antigens.

• Biomolecules & Therapeutics
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• v.21 no.1
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• pp.35-41
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• 2013

Metformin is widely used for T2D therapy but its cellular mechanism of action is undefined. Recent studies on the mechanism of metformin in T2D have demonstrated involvement of the immune system. Current immunotherapies focus on the potential of immunomodulatory strategies for the treatment of T2D. In this study, we examined the effects of metformin on the antigen-presenting function of antigen-presenting cells (APCs). Metformin decreased both MHC class I and class II-restricted presentation of OVA and suppressed the expression of both MHC molecules and co-stimulatory factors such as CD54, CD80, and CD86 in DCs, but did not affect the phagocytic activity toward exogenous OVA. The class II-restricted OVA presentation-regulating activity of metformin was also confirmed using mice that had been injected with metformin followed by soluble OVA. These results provide an understanding of the mechanisms of the T cell response-regulating activity of metformin through the inhibition of MHC-restricted antigen presentation in relation to its actions on APCs.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.205.1-205.1
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• 2003

Bifidobacterium spp. is nonpathogenic. Gram-positive and anaerobic bacteria, which inhabit the intestinal tract of humans and animals. Bifidobacterium spp. plays important roles in human health. However. the influence of exogenous factors on species composition of fecal bifidobacteria is still unclear. In this study, we wished to determine whether presentation of exogenous OVA (10 $\mu\textrm{g}$/$m\ell$) could be enhanced by the culture supernatant of ten Bifidobacterium spp. (omitted)

• Natural Product Sciences
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• v.19 no.4
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• pp.347-354
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• 2013

Cordyceps militaris, a traditional medicinal mushroom, produces a component compound, cordycepin (3'-deoxyadenosine). Cordycepin has many pharmacological activities including immunological stimulating, anti-cancer, and anti-infection activities. However, the therapeutic mechanism has not yet been elucidated. In this study, we examined the effects of cordycepin on the antigen-presenting function of antigen-presenting cells (APCs). Dendritic cells (DCs) were cultured in the presence of cordycepin and then allowed to phagocytose microspheres containing ovalbumin (OVA). After washing and fixing, the efficacy of OVA peptide presentation by DCs was evaluated using CD8 and CD4 T cells. Also, we confirmed the protein levels of proinflammatory cytokines through RT-PCR and Western blot analysis. Cordycepin decreased both MHC class I and class II-restricted presentation of OVA and suppressed the expression of both MHC molecules and the phagocytic activity toward exogenous OVA. The class II-restricted OVA presentation-regulating activity of cordycepin was also confirmed using mice that had been injected with cordycepin followed by soluble OVA. Furthermore, cordycepin suppressed the mRNA and protein levels of iNOS, COX-2, pro-inflammatory cytokines in a concentration-dependent manner. These results provide an understanding of the mechanism of the T cell response-regulating activity of cordycepin through the inhibition of MHC-restricted antigen presentation in relation to its actions on APCs.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.136.2-136.2
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• 2003

Previously, we showed that cyclosporin A and tacrolimus, but not rapamycin, inhibit MHC class I-restricted presentation of exogenous antigen in dendritic cells (DCs). We further characterized the effects of cyclosporin A and tacrolimus on the uptake, processing and cross-presentation of a model antigen, ovalbumin (OVA), in DCs. Treatment of DCs with cyclosporin A or tacrolimus did not inhibit phagocytic activity of DCs. Instead, treatment of DCs with cyclosporin A or tacrolimus inhibited the expression of $H-2K^b$/ molecules complexed with the OVA peptied, SIINFEKL, specifically. (omitted)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.306.2-306.2
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• 2002

The main targets for the immunosuppressive calcineurin inhibitors. tacrolimus (FK-506) and cyclosporine A (CsA). have been considered to be activated T cells. but not antigen presenting cells (APCs). In the present study. we examined the effects of these drugs on the MHC-restricted presentation of exogenously added antigen. ovalbumin (OVA). in dendritic cells (DCs). Particulate form of OVA was efficiently captured. processed and presented on class I MHC molecules (cross-presentation) as well as on class II MHC molecules. (omitted)

• IMMUNE NETWORK
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• v.10 no.4
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• pp.135-143
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• 2010

Background: Cordyceps militarys water extract (CME) has been reported to exert antitumor and immunomodulatory activities in vivo and in vitro. However, the therapeutic mechanism has not yet been elucidated. In this study, we examined the effects of CME on the antigen presenting function of antigen presenting cells (APCs). Methods: Dendritic cells (DCs) were cultured in the presence of CME, and then allowed to phagocytose microspheres containing ovalbumin (OVA). After washing and fixing the efficacy of OVA, peptide presentation by DCs were evaluated using CD8 and CD4 T cells. Also, we confirmed the protein levels of proinflammatory cytokines through western blot analysis. Results: CME enhanced both MHC class I and class II-restricted presentation of OVA in DCs. In addition, the expression of both MHC class I and II molecules was enhanced, but there was no changes in the phagocytic activity of exogenous OVA. Furthermore, CME induced the protein levels of iNOS, COX-2, proinflammatory cytokines, and nuclear p65 in a concentration-dependent manner, as determined by western blot. Conclusion: These results provide an understanding of the mechanism of the immuno-enhancing activity of CME on the induction of MHC-restricted antigen presentation in relation to their actions on APCs.

• Archives of Pharmacal Research
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• v.29 no.12
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• pp.1147-1153
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• 2006

Mizoribine (MZR) has been shown to possess immunosuppressive activity that selectively inhibits the proliferation of lymphocytes by interfering with inosine monophosphate dehydrogenase. The efficacy of MZR is not only in patients who have had renal transplantation, but also in patients with rheumatoid arthritis (RA), lupus nephritis, and primary nephritic syndrome. Because the exact mechanism of its immunosuppressive action is not clear, the object of this study was to examine the ability of MZR to regulate the antigen presenting cells (APCs), dendritic cells (DCs). In this work, we tested whether MZR ($1{\sim}10\;{\mu}g/mL$) could inhibit the cross-presentation of DCs. DC2.4 cells ($H-2K^{b}$) or bone marrow-derived DCs (BM-DCs) generated from BM cells of C57BL/6 mouse ($H-2K^{b}$) were cultured in the presence of MZR with OVA-microspheres, and the amount of OVA peptide-class I MHC complexes was measured by a T cell hybridoma, B3Z, that recognizes OVA (257-264 : SIINFEKL)-$H-2K^{b}$ complex and expresses-galactosidase. MZR profoundly inhibited the expression of SIINFEKL-$H-2K^{b}$ complexes. This inhibitory activity of MZR appeared to affect the phagocytic activity of DCs. MZR also decreased IL-2 production when we examined the effects of MZR on $CD4^{+}$ T cells. These results provide an understanding of the mechanism of immunosuppressive activity of MZR on the inhibition of MHC-restricted antigen presentation and phagocytic activity in relation to their actions on APCs.