• IMMUNE NETWORK
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• v.11 no.6
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• pp.412-415
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• 2011

Hypocrellin A has gained much attention in recent years due to its light-induced antitumor, antifungal and antiviral activities. Here we report that hypocrellin A exerts immunomodulatory effects on MHC-restricted presentation of antigen. Hypocrellin A inhibited class II-MHC restricted presentation of exogenous antigen, but not class I MHC-restricted presentation of exogenous antigen, in dendritic cells. Hypocrellin A also inhibited the cytosolic pathway of endogenous antigen presentation. However, hypocrellin A did not inhibit the expression of class I and class II MHC molecules on dendritic cells (DCs), the phagocytic activity of DCs, or the $H-2K^b$-restricted presentation of a synthetic peptide, SIINFEKL. These results show that hypocrellin A differentially modulates the MHC-restricted antigen presentation pathways.

• Parasites, Hosts and Diseases
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• v.36 no.1
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• pp.37-46
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• 1998

A Czonorchis sinensis-specific antigen in excretory-secretory product of C. sinensis (CsE) was assessed in human clonorchiasis by immunoblot. Thirty and 7 kDa antigens of CsE2, one of four different batches of CsEs reacted strongly with infection sera from clonorchiasis patients; however, the antigens reacted weakly with 6-month post- treatment sera from praziquantel-cured cases, but were still highly detected by the sera from praziquantel∼failed patients, indicating that the 30 and 7 kDa antigens can detect antibodies during an active infection. The 30 kDa antigen showed some cross reactions with sera from patients with Pcragonimus westemani and Metcfonimw vokogcujci, while the 7 kDa antigen did not, suggesting that the 7 kDa antigen has high specificity. The 30 kDa antigen reacted with some past clonorchiasis sera, whereas the 7 kDa antigen did not, supporting that antibodies to the 7 kDa antigen are not present in sera from past clonorchiasis patients. In an endemic area, 92% (23/25) of active clonorchiasis patients and 91% (10/11) of mixed infection patients with C. sinensis and M. Wokosawai had IgG antibodies to the 7 kDa antigen, while 40% (6/15) of past clonorchiasis individuals and 43% (3/7) of metagonimiasis patients cross-reacted to the antigen. These data suggest that the 7 kDa antigen in an excretory-secretory antigen may serve as a marker of an active clonorchiasis with reliable specificities in past clonorchiasis, paragonimiasis and metagonimiasis.

• BMB Reports
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• v.55 no.2
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• pp.57-64
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• 2022

Autoimmune disease is known to be caused by unregulated self-antigen-specific T cells, causing tissue damage. Although antigen specificity is an important mechanism of the adaptive immune system, antigen non-related T cells have been found in the inflamed tissues in various conditions. Bystander T cell activation refers to the activation of T cells without antigen recognition. During an immune response to a pathogen, bystander activation of self-reactive T cells via inflammatory mediators such as cytokines can trigger autoimmune diseases. Other antigen-specific T cells can also be bystander-activated to induce innate immune response resulting in autoimmune disease pathogenesis along with self-antigen-specific T cells. In this review, we summarize previous studies investigating bystander activation of various T cell types (NKT, γδ T cells, MAIT cells, conventional CD4⁺, and CD8⁺ T cells) and discuss the role of innate-like T cell response in autoimmune diseases. In addition, we also review previous findings of bystander T cell function in infection and cancer. A better understanding of bystander-activated T cells versus antigen-stimulated T cells provides a novel insight to control autoimmune disease pathogenesis.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2003.06a
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• pp.55-62
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• 2003

The mucosal immune system provides a first line of defense against invasion of infectious agents via inhalation, ingestion and sexual contact. For the induction of protective immunity at these invasion sites, one must consider the use of the CMIS, which interconnects inductive tissues, including PP and NALT, and effector tissues of the intestinal, respiratory and genitourinary tracts. In order for the CMIS to induce maximal protective mucosal immunity, co-administration of mucosal adjuvant or use of mucosal antigen delivery vehicle has been shown to be essential. When vaccine antigen is administered via oral or nasal route, antigen-specific Th 1 and Th2 cells, cytotoxic T lymphocytes(CTLs) and IgA B cell responses are effectively induced by the CMIS. In the early stages of induction of mucosal immune response, the uptake of orally or nasally administered antigens is achieved through a unique set of antigen-sampling cells, M cells located in follicle-associated epithelium(FAE) of inductive sites. After successful uptake, the antigens are immediately processed and presented by the underlying DCs for the generation of antigen-specific T cells and IgA committed B cells. These antigen-specific lymphocytes are then home to the distant mucosal effector tissues for the induction of antigen-specific humoral(e.g., IgA) and cell-mediated (e.g., CTL and Th1) immune responses in order to form the first line of defense. Elucidation of the molecular/cellular characteristics of the immunological sequence of mucosal immune response beginning from the antigen sampling and processing/presentation by M cells and mucosal DCs followed by the effector phase with antigen-specific lymphocytes will greatly facilitate the design of a new generation of effective mucosal antigen-specific lymphocytes will greatly facilitate the design of a new generation of a new generation of effective mucosal adjuvants and of a vaccine deliver vehicle that maximizes the use of the CMIS.

• 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.

• Journal of Life Science
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• v.26 no.9
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• pp.1027-1032
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• 2016

Antigen is substance causing disease derived from pathogen. Living organism has the immune system in terms of defense mechanism against antigen. Antigen is processed through several pathways such as phagocytosis, antibody action, complement activation, and cytotoxins by NK or cytotoxic T lymphocyte via MHC molecule. Lymph node (LN) is comprised of the complicated 3 dimensional network and several stromal cells. Fibroblastic reticular cells (FRC) are distributed in T zone for interaction with T cells. FRC produces the extra cellular matrix (ECM) into LN for ECM reorganization against pathogen infections and secretes homing chemokines. However, it has not so much been known about the involvement of the antigen process of FRC. The present report is for the function of FRC on antigen process. For this, FRC was positioned with several infected situations such as co-culture with macrophage, T cell, lipopolysaccharide (LPS) and TNFα stimulation. When co-culture between FRC with macrophage and T cells was performed, morphological change of FRC was observed and empty space between FRCs was made by morphological change. The matrix metallo-proteinase (MMP) activity was up-regulated by Y27632 and T cells onto FRC. Furthermore, inflammatory cytokine, TNFα regulated the expression of adhesion molecules and MHC I antigen transporter in FRC by gene chip assay. NO production was elevated by FRC monolayer co-cultured with macrophage stimulated by LPS. GFP antigen was up-taken by macrophage co-cultured with FRC. Collectively, it suggests that FRC assists of the facilitation of antigen process and LN stroma is implicated into antigen process pathway.

• Parasites, Hosts and Diseases
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• v.47 no.1
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• pp.65-68
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• 2009

Excretory-secretory products of Toxocara canis larvae have been considered as a major functional antigen in immune responses against toxocariasis. We studied ultrastructural localization of T. canis second-stage larval antigen using a seropositive human serum under immunogold electron microscopy. High-density gold particles were observed in the secretory cells, excretory duct, intestinal epithelium, and cuticle of the larval worm sections. The distribution of the positive reactions in the larval worms suggests that the nature of the antigen is excretory-secretory antigen including waste metabolites and secretory enzymes.

• Animal cells and systems
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• v.11 no.1
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• pp.33-38
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• 2007

Liposome-entrapped atypical Aeromonas hydrophila antigen was prepared to investigate the potential protective efficacy for A. hydrophila infection. Carp (Cyprinus carpio) were immunized orally with liposome-entrapped A. hydrophila antigen. After immunization, significantly more antigen-specific antibodies were detected in serum, intestinal mucus and bile than non-immunized control group. The immunized carp were then challenged by immersion with $1{\times}10^{6}$ cfu/ml of A. hyrdophila for 60 min. Of the eight non-immunized carp, three carp died (62.5% survival), whereas five out of six (83.5%) of the immunized survived. Furthermore, development of skin ulcers was significantly inhibited in carp immunized with liposomes containing A. hydrophila antigen. These results suggest that liposomes containing A. hydrophila antigen have a potential for induction of protective immune responses against atypical A. hydrophila infection and also suggest the possibility of developing a vaccine that may ultimately be used for prevention of fish diseases.

• Korean Journal of Microbiology
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• v.28 no.1
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• pp.1-5
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• 1990

The coding sequence of hepatitis B viral core antigen (HBcAg) (subtype adr) contains two in-phase initiation codons, one for precore and the other for core antigen gene. To study the expression of core antigen and the role of precore region, the coding sequence of HBcAg with or without precore (pre-C) region were subcloned into yeast expression vector containing phosphoglycerate kinase (PGK) promoter. To study the role of upstream region in the expression of the core antigen, a series of 5' deletion mutants were also subcloned into the vector. After transformation into various host strains, the expression of HBcAg were analysed by radio-immunoassat. Under optimal condition of core antigen gene expression in yeast, the highest amount of antigen was detected in the cell line SHY4 containing pGKHBc plasmid composed of the yeast PGK gene promoter, terminator and C-gene. Regardless of the presence of precore region, core antigen was not detected in the medium but in cell extract. These results suggest that precore region cannot affect the secretion of core antigen in Saccharomyces cerevisiae.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.1
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• pp.141-146
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• 1997

Postmortem examination was conducted on 350 (three hundred and fifty) chickens. Related samples (Liver, heart, ovary, spleen, bone-marrow, and caecal junction) were collected. The appropriate materials from the samples were cultured into different media. A total 40(forty) isolates of salmonella pullorum and S. gallinarum were identified and preserved. Characterization of the isolates were done by cultural, morphological, biochemical, and serological tests. Salmonella pullorum antigen was prepared from the local isolate, standardized and tested. This antigen was used in the field for the detection of pullorum or fowl typhoid infection or carrier birds. The antigen consisted of suspension of Salmonella pullorum in 0.50 percent sodium chloride plus 1.5 percent sodium sulfate and inactivated with 1% formalin U.S.P. and standardized with McFarland scale iv or by pour plate method containing 800 million organisms per milliliter and stained by the addition of alcoholic crystal violet. Sterility, safety and potency were tested and found as good as other international antigens. The antigen was found to retain its quality for six months when preserved at room temperatures. The test was made by mixing one drop of the antigen with a drop of blood or a drop of serum, on a glass plate or white tile. The locally produced antigen was as good as antigens from Japan, Hungary, Holland and India. A serological study was conducted with the locally prepared antigen in different farms, and the incidence was 0-4% in government farms, 5-10% in commercial imported breeds and 0-3% in cross breed local farms respectively.