• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.823-828
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• 2000

The complete nucleotide sequence of hepatitis B virus DNA isolated from Korean patient serum was determined and characterized, and its phylogenetic relation was then investigated. The viral genome was 3,215 base pairs long and included four well known open reading frames (i.e. surface antigens, core antigens, X protein and DNA polymerase). The sequence of the surface antigen showed that the HBV genome under investigation, designated HBV 315, was characteristic of subtype adr. A phylogenetic analysis using the total genome sequence revealed that HBV315 was grouped into genomic group C together with isolates from Japan, China, Thailand, Polynesia, and New Caledonia. The mean percent similarity between HBV315 and other HBV isolates in genomic group C was 97.25%, and that with other genomic groups ranged from 86.16% to 91.25%. The predicted amino acid sequences of HBV315 were compared with two closely related subtype adr isolates, M38636 and D12980. The results showed that the X gene product was identical in the three strains, while there were significant amino acid sequence differences between HBV315 and M38636 in the Pre-S1 and Pre-S2 regions.

• International Journal of Oral Biology
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• v.42 no.2
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• pp.63-70
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• 2017

Selecting an appropriate antigen with optimal immunogenicity and physicochemical properties is a pivotal factor to develop a protein based subunit vaccine. Despite rapid progress in modern molecular cloning and recombinant protein technology, there remains a huge challenge for purifying and using protein antigens rich in hydrophobic domains, such as membrane associated proteins. To overcome current limitations using hydrophobic proteins as vaccine antigens, we adopted in silico analyses which included bioinformatic prediction and sequence-based protein 3D structure modeling, to develop a novel periodontitis subunit vaccine against the outer membrane protein FomA of Fusobacterium nucleatum. To generate an optimal antigen candidate, we predicted hydrophilicity and B cell epitope parameter by querying to web-based databases, and designed a truncated FomA (tFomA) candidate with better solubility and preserved B cell epitopes. The truncated recombinant protein was engineered to expose epitopes on the surface through simulating amino acid sequence-based 3D folding in aqueous environment. The recombinant tFomA was further expressed and purified, and its immunological properties were evaluated. In the mice intranasal vaccination study, tFomA significantly induced antigen-specific IgG and sIgA responses in both systemic and oral-mucosal compartments, respectively. Our results testify that intelligent in silico designing of antigens provide amenable vaccine epitopes from hard-to-manufacture hydrophobic domain rich microbial antigens.

• Korean Journal of Veterinary Research
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• v.42 no.2
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• pp.209-217
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• 2002

This study was performed to produce monoclonal antibodies (mAb) specifically reacting with chicken leukocyte surface antigens. Popliteal lymph node cells of BALB/c mice previously immunized through foot-pad with peripheral blood mononuclear cells (PBMC) of chickens separated by Ficoll-Histopaque method. They were fused with P3X63Ag14 mouse myeloma cells. A total of 34 hybridomas secreted antibodies specifically binding to the PBMC. According to the reactivity patterns with PBMC, the mAbs were divided into 4 groups. Group 1 mAbs (IIB3, IIB10, IIE10) specifically reacted with non-adherent lymphocytes but not with adherent cells which were mainly composed of thrombocytes and monocytes in PBMC culture. These mAbs were reactive with 25-59% of thymus cells and 42-64% of spleen cells of chickens. They did not show any significant reactivity with cells in the bursa of Fabricius, T-cell (MDCC-MSB1) and B-cell (LSCC-1104B1) lines. These results indicate that Group I mAbs specifically reacted with T-lymphocyte subpopulation. Monoclonal antibodies in Group II (IC6, IG2-2 and IID9) showed specific reactivity with monocytes but not with thrombocytes or non-adherent cells in PBMC culture. These mAbs, though not reacted with the chicken macrophage cell line, HD11, also bound to macrophages of the spleen and lung in immunohistochemical staining. Five mAbs in Group III showed characteristics of binding to lymphocytes and monocytes, but not to thrombocytes. Twenty-three mAbs in Group IV showed specific reactivity to lymphocytes, monocytes, and thrombocytes. Two mAbs (IC3 and IE9) in Group IV reacted with most of PBMC.

• Molecules and Cells
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• v.44 no.5
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• pp.310-317
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• 2021

Cluster of differentiation 1 (CD1) is a family of cell-surface glycoproteins that present lipid antigens to T cells. Humans have five CD1 isoforms. CD1a is distinguished by the small volume of its antigen-binding groove and its stunted A' pocket, its high and exclusive expression on Langerhans cells, and its localization in the early endosomal and recycling intracellular trafficking compartments. Its ligands originate from self or foreign sources. There are three modes by which the T-cell receptors of CD1a-restricted T cells interact with the CD1a:lipid complex: they bind to both the CD1a surface and the antigen or to only CD1a itself, which activates the T cell, or they are unable to bind because of bulky motifs protruding from the antigen-binding groove, which might inhibit autoreactive T-cell activation. Recently, several studies have shown that by producing T_H2 or T_H17 cytokines, CD1a-restricted T cells contribute to inflammatory skin disorders, including atopic dermatitis, psoriasis, allergic contact dermatitis, and wasp/bee venom allergy. They may also participate in other diseases, including pulmonary disorders and cancer, because CD1a-expressing dendritic cells are also located in non-skin tissues. In this mini-review, we discuss the current knowledge regarding the biology of CD1a-reactive T cells and their potential roles in disease.

• Parasites, Hosts and Diseases
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• v.39 no.2
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• pp.171-176
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• 2001

Western blot analysis was performed to diagnose vivax malaria using stage-specific recombinant antigens. Genomic DNA from the whole blood of a malaria patient was used as templates to amplify the coding regions for the antigenic domains of circumsporozoite protein (CSP-1), meroxoite surface protein (MSP-1), apical merozoite antigen (AMA- 1), serine repeat antigen (SERA), and exported antigen (EXP- 1) of Plasmodium vivax. Each amplified DNA fragment was inserted into a pGEX-4T plasmid to induce the expression of GST fusion protein in Escherichia coli by IPTG. The bacterial cell extracts were separated on 10% SDS-PAGE followed by western blot analysis with patient sera which was confirmed by blood smear examination. When applied with patient sera, 147 (91.9%) out of 160 vivax malaria, 12 (92.3%) out of 13 falciparum malaria, and all 9 vivax/falciparum mixed malaria reacted with at least one antigen, while no reactions occurred with 20 normal uninfected sera. In the case of vivax malaria, CSP-1 reacted with 128 (80.0%) sera, MSP-1 with 102 (63.8%), AMA-1 with 128 (80.0%), SERA with 115 (71.9%), and EXP-1 with 89 (55.6%), respectively. We obtained higher detection rates when using S antigens (91.9%) rather than using each antigen solely (55.6 - 80%), a combination of 2 (76.3 - 87.5%), 3 (85.6 - 90.6%), or 4 antigens (89.4 - 91.3%). This method can be applied to serological diagnosis, mass screening in endemic regions, or safety test in transfusion of prevalent vivax malaria.

• Journal of Pharmaceutical Investigation
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• v.41 no.3
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• pp.185-190
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• 2011

The purpose of this study was to evaluate the phagocytic uptake of surface modified PLGA microspheres containing ovalbumin (OVA) into dendritic cell. In order to find the most suitable formulation for targeted delivery to antigen presenting cells (APC), OVA was encapsulated by a double emulsion solvent evaporation method with three PLGA microspheres (PLGA 50:50, PLGA 75:25 and PLGA 85:15) and two surface modified microspheres by chitosan and sodium dodecyl sulfate (SDS). Physicochemical properties were evaluated in terms of size, zeta potential, encapsulation efficiency, different scanning calorimeter (DSC), x-ray diffraction, morphology, and OVA release test from microspheres. Phagocytic activity was estimated using dendritic cells and analyzed by fluorescence activated cell sorter (FACS). The result showed that zeta potential of PLGA particles was changed to positive by the chitosan modification. The release profile of chitosan modified PLGA microspheres exhibited sustained release after initial burst. The chitosan modified microspheres had higher phagocytic uptake than the other microspheres. Such physicochemical properties and phagocytic uptake studies lead us to conclude that chitosan modified microspheres is more suitable formulation for the targeted delivery of antigens to APC compared with the other microspheres.

• Korean Journal of Veterinary Research
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• v.34 no.4
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• pp.805-813
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• 1994

Immunohistochemical study on the intestinal tissues obtained from the 21 pigs of the 14 terms in Korea in which the clinical and epidemiological features had indicated the possible outbreaks of porcine epidemic diarrhea(PED) was performed using the indirect immunofluorescence test and/or the immunoperoxidase method in order to detect PED viral antigens in the infected cells of the intestines, and histopathological features were described as well. By immunohistochemical analysis, PED viral antigens were detected in the epithelial cells covering the small intestinal villi and recognized slightly in the cells lining the colonic surface epithelium as well. Occasional fluorescence was also seen in a few intestinal crypt epithelium. On light microscopy, the piglets with PED showed marked villous atrophy and fusion, and severe enterocyte degeneration and desquamation. On the other hand, the older pigs more than 4 week old age was mild villous atrophy and fusion, severe villous epithelial cell proliferation, and moderate mononuclear cell infiltration.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.2
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• pp.97-108
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• 2011

Cancer stem cells have stem cell-like features, such as the ability for self-renewal and differentiation but show unlimited growth because they have the lost normal regulation of cell growth. Cancer stem cells and normal stem cells have similar features. They show high motility, diversity of progeny, robust proliferative potential, association with blood vessels, immature expression profiles, nestin expression, epidermal growth factor (EGF)-receptor expression, phosphatase and tensin homolog (PTEN) expression, hedgehog pathway activity, telomerase activity, and Wnt pathway activity. On the other hand, with cancer cells, some of these signaling pathways are abnormally modified. In 1875, Cohnheim suggested the concept of cancer stem cells. Recently, evidence for the existence of cancer stem cells was identified. In 1994, the cancer stem cells' specific cell surface marker for leukemia was identified. Since then, other specific cell surface markers for cancer stem cells in solid tumors (e.g. breast and colon cancer) have been identified. In oral cancer, studies on cancer stem cells have been performed mainly with squamous cell carcinomas. Oral cancer specific cell surface markers, which are genes strongly expressed in oral cancer and cancer stem cell specific side populations, have been identified. Cancer stem cells are resistant to radiotherapy and chemotherapy. Therefore, to eliminate malignant tumors efficiently and reduce the recurrence rate, therapy targeting cancer stem cells needs to be performed. Currently, studies targeting the cancer stem cells' specific signaling pathways, telomerase and tumor vasculatures are being done.

• 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.

• Korean Journal of Veterinary Service
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• v.45 no.4
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• pp.269-275
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• 2022

Blood type in dogs is based on the antigen present on the red blood cell surface. Dog erythrocyte antigen 1 is a crucial red blood cell antigen in dogs, whereas the dog erythrocyte antigen 7 has been studied in limited dog breeds worldwide. To assess the prevalence of dog erythrocyte antigens 1 and 7 in 11 breeds in the Republic of Korea, 624 dog blood samples were examined for antigen detection. Overall, 520 dogs (83.3%) showed dog erythrocyte antigen 1 expression. The distribution varied from 50.0~100.0% according to the breed. Dog erythrocyte antigen 1-positive blood type was the highest in Chihuahua (100%), followed by Jindo dog (98.5%), and Sapsaree (95.3%). Dog erythrocyte antigen 7 was positive in 125 dogs (20.0%), and the positivity varied from 5.0~42.9% according to the breed. Dog erythrocyte antigen 7-positive blood type was the highest in Beagle (42.9%), followed by Chihuahua (37.5%), and Jindo dog (27.8%). The high prevalence of dog erythrocyte antigen 1 is because of the high proportion of Jindo dog and Sapsaree breeds that were mostly positive for the antigen. The high abundance of these breeds could be due to inbreeding and local breeding in the Republic of Korea. To our best knowledge, this study is the first to report on the prevalence of dog erythrocyte antigens 1 and 7 among various canine breeds in the Republic of Korea. The prevalence data obtained from this study may contribute to baseline information on veterinary transfusion medicine in small animal practice.