• 미생물학회지
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• 제16권1호
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• pp.30-40
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• 1978

Detergent soluble fractions were obtained from T. ferrooxidans ATCC 13598 and the T. thiooxidans ATCC 8085 which were treated with 3% of Tween 20. The detergent soluble antigen(crude antigen) fractions of the T.ferrooxidans and the T.thiooxidans were subjected to hydroxyapatite. In the case of T.thiooxidans, further purification was carried out on the DEAE-cellulose column chromatography. The antigen fractions, such as the hydroxyapatite peak-1(Tf, HA-1) and peak-2 from T.ferrooxidans(Tf. HA-2) and hydroxyapatite peak-1(Tt, HA-1), DEAE-cellulose peak-1(Tt, DP-1) and peak-2(Tt, DP-2) from T. thiooxidans wre compared each other with the homologous and the heterologous and the heterologous antisera against to the Thiobacillus species. The hydroxyapatite peak-2 fraction from the T.ferrooxidans(Tf, HA-2) and DEAE-cellulose peak-2 fraction from the T.thiooxidans(Tt, DP-2) were represented the type-specific immuno-reactivities between the T.ferrooxidans and the T.thiooxidans on the several sets of double gel diffusioin analysis. The type-specific antigen fractions from both of the baceteria were mainly composed of protein with entierly different electrophoretic mobility on the SDS-polyacrylamide gel electrophoresis. However, the PAS positive banding patterns on the electrophorogram showed wide range of common antigenic properties in the T. ferrooxidans and the T.thiooxidans, respectively.

• Biomolecules & Therapeutics
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• 제21권1호
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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.

• BMB Reports
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• 제30권6호
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• pp.415-420
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• 1997

Although $CD4^+$ T cell responses to protein-derived antigen have well been understood, the epitopes recognized by hapten-specific $CD4^+$ T cells have not been fully defined. In this study, we characterized the response of a T cell hybridoma (5Di0.1B8) which is specific for a hapten. N-hydroxysuccinimidyl-4-azidobenzoate (HSAB) restricted by MHC class II $I-A^d$. Using three different antigen presenting cells (APCs) expressing $I-A^d$, the role of class II MHC proteins in haptenic antigen presentation and subsequent activation of 5D10.1B8 has been examined. Activation of 5D10.1B8 T cells by HSAB analogs was also performed. Our results show that each APC activated T cells differentially and that interleukin-2 (IL-2) augmented antigen-presenting ability of all the APCs, suggesting that increased expression of class II MHC protein by IL-2 played an important role in HSAB presentation and T cell activation. Finally, early T cell receptor-dependent signals induced by HSAB or its analogs were examined by phosphotyrosine immunoblot analysis, and showed that tyrosine phosphorylation level of a 18-20 kD protein increased upon stimulation.

• 대한수의학회지
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• 제39권1호
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• pp.159-168
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• 1999

Swine whipworm(Trichuris suis) is cosmopolitan nematode which can cause serious pathology in immature stage(larva2~larva5) of infected pigs, such as anorexia, diarrhea, anemia, and death in heavy infections. In this larval stages, it is very difficult to diagnose the infection of whipworm and to differentiate from other common swine gastrointestinal disorders such as 21 day scours which are associated with TGE virus, rota virus, coccidium, and the stress of weaning. In this experiment, the isolated antigens of Trichuris spp. were carried out to examine the structure and specificity of antigens and to select the reasonable antigens which would be used in serological diagnosis by electrophoresis, Western blotting, ELISA. The results of this experiment were as follows; 1. The common fractions of each Trichuris suis antigen were identified 28,32,45, 80kDa by SDS-PAGE with silver stain and four major fractions could be detected in positive swine sera by Western blot analysis. 2. The OD(optical density) values of somatic and excretory-secretory antigens which were reacted against positive(negative) sera from pigs infected with Trichuris suis by ELISA reader were; 1) OD values($mean{\pm}SD$) of adult somatic antigen against positive(negative) sera were $0.30{\pm}0.12(0.09{\pm}0.006)$ and third-stage larva of somatic antigen were $0.28{\pm}0.038(0.10{\pm}0.005)$. And OD values of excretory-secretory antigens of adult and third-stage larva were $0.24{\pm}0.031(0.11{\pm}0.005)$ and $0.08{\pm}0.013(0.10{\pm}0.003)$, respectively. 2) OD values of adult somatic, larval somatic antigen and adult excretory-secretory antigen response to positive sera were significantly (p<0.01) associated with negative swine sera. And the Cut-off OD values(minimum positive value) were determined to be mean negative value plus 3 SD that would minimized the risk of false positives. 3. The OD values of somatic antigens of T suis and T vulpis against swine positive(negative) sera were $0.30{\pm}0.120(0.09{\pm}0.006)$ and $0.25{\pm}0.141(0.09{\pm}0.003)$. These data mean that the somatic antigens of T suis and T vulpis were able to diagnose T vulpis infection in dogs as well as T suis infection in pigs. These results suggest that somatic antigen of third-stage larva and excretory-secretory antigen of adult T suis could be used the diagnostic antigen by serological test(ELISA) in immature Trichuris spp. infection.

• 대한수의학회지
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• 제44권2호
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• pp.269-277
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• 2004

Trichinella spiralis is one of the important zoonotic parasites with a wide variety of vertebrates hosts in nature. The purpose of this study were to analyze ESP(Excretory-Secretory Protein) antigen, to evaluate ELISA for the serological diagnosis of Trichinosis, and to survey T. spiralis infection in finishing pigs using the pepsin digestion method and ELISA in Korea. In the analysis of ESP antigen by SDS-PAGE and Western blot, 4 major bands (70, 55, 52.6, and 49 kDa) were revealed from the ESP antigen. Predilection sites of T. spiralis were the diaphragm, the tongue, masseter muscles, intercostal muscle, and hindlimb in orders in the experimentally infected rats. Sera from 581 swine were tested by ELISA with ESP antigen. The 54 (9.3%) sera were suspected as positive reactors, however, these 54 sera were determined as false positives by the use of Western blotting. This study demonstrated that the ELISA was not suitable for the examination of T. spiralis in pork. The diaphragm muscle samples of 251 finishing pigs were tested by the method of pepsin-digestion for the presence of Trichinella larvae, however, T. spiralis was not detected from the samples. We could not find out T. spiralis infection in pig in Korea pork.

• Archives of Pharmacal Research
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• 제25권2호
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• pp.208-213
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• 2002

The human polyomavirus JC virus is the etiologic agent of progressive multifocal leukoencephalopathy (PML). As the JC virus early promoter directs cell-specific expression of the viral replication factor large T antigen, transcriptional regulation constitutes a major mechanism of glial tropism in PML. It has been demonstrated that SV4O or JC virus large T antigen interacts with p53 protein and regulates many viral and cellular genes. In this study we founts that p53 represses the JC virus early promoter in both glial and nonglial cells To identify the cis-regulatory elements responsible for p53-mediated repression, deletional and site-directed mutational analyses were performed . Deletion of the enhancer region diminished p53-mediated transcriptional repression. However, point mutations of several transcription factor binding sites in the basal promoter region did not produce any significant changes. In support of this observation, when the enhancer was fused to a heterologous promoter, p53 red reduced the promoter activity about three fold. These results indicate that the enhancer region is important for tole repression of JC virus transcription by p53. Furthermore, coexpression of JC virus T antigen with a p53 protein abolished p53-mediated repression of the JC virus early promoter in non-glial cells, but not in glial cells. This finding suggests that T antigen interacts with p53 and regulates JC virus transcription in a cell-specific manner.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.78-79
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• 2003

T cell activation is initited by the interaction of T cells with antigen-presenting cells (APCs) in the context of peptide antigen. Initial conjugates are formed by binding between lymphocyte-associated antigen-l (LFA-l, also known as CD11a-CD18) and intercellular adhesion molecule-l (ICAM-1), or CD2 and LFA-3, or other pairs of interactive proteins. (omitted)

• Molecules and Cells
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• 제45권8호
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• pp.513-521
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• 2022

Cytotoxic T lymphocyte antigen-4 (CTLA-4) is an immune checkpoint molecule that is mainly expressed on activated T cells and regulatory T (Treg) cells that inhibits T-cell activation and regulates immune homeostasis. Due to the crucial functions of CTLA-4 in T-cell biology, CTLA-4-targeted immunotherapies have been developed for autoimmune disease as well as cancers. CTLA-4 is known to compete with CD28 to interact with B7, but some studies have revealed that its downstream signaling is independent of its ligand interaction. As a signaling domain of CTLA-4, the tyrosine motif plays a role in inhibiting T-cell activation. Recently, the lysine motif has been shown to be required for the function of Treg cells, emphasizing the importance of CTLA-4 signaling. In this review, we summarize the current understanding of CTLA-4 biology and molecular signaling events and discuss strategies to target CTLA-4 signaling for immune modulation and disease therapy.

• IMMUNE NETWORK
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• 제22권1호
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• pp.6.1-6.19
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• 2022

Chimeric antigen receptor (CAR) T cells, which express a synthetic receptor engineered to target specific antigens, have demonstrated remarkable potential to treat haematological malignancies. However, their transition beyond haematological malignancy has so far been unsatisfactory. Here, we discuss recent challenges and improvements for CAR T cell therapy against solid tumors: Antigen heterogeneity which provides an effective escape mechanism against conventional mono-antigen-specific CAR T cells; and the immunosuppressive tumor microenvironment which provides physical and molecular barriers that respectively prevent T cell infiltration and drive T cell dysfunction and hypoproliferation. Further, we discuss the application of CAR T cells in infectious disease and autoimmunity.

• Parasites, Hosts and Diseases
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• 제45권1호
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• pp.19-26
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• 2007

This study describes the isolation of a Toxocara canis species-specific excretory-secretory(ES) antigen and the development of an enzyme-linked immunosorbent assay(ELISA) based on this antigen. Analysis of the ES antigens of T. canis, Toxocara vitulorum, Ascaris lumbricoides and Necator americanus larval antigen was performed by SDS-PAGE followed by western blotting. A 57 kDa T. canis-specific antibody fraction(TcES-57) was identified by western blotting and labelling with anti-Toxocara antibodies(from experimental rabbits and human patients) and tracing with anti-human or anti-rabbit peroxidase conjugate. No protein fraction of 57 kDa was detected in ES or larval antigens collected from T. canis, T. vitulorum, A. lumbricoides and N. americanus. Using TcES-57, a specific anti-serum was produced in rabbits and a double sandwich ELISA was developed. This test was validated using known seropositive sera from toxocariasis patients, sera from A. lumbricoides or N. americanus patients, and 50 serum samples from cats. These tests revealed that TcES-57 antigen is specific to T. canis infection and does not cross react with sera of other related infections. Thus, ELISA based on TcES-57 antigen was proven to be an effective tool in the diagnosis of toxocariasis and studies on the role of T. canis in the epidemiology of human toxocariasis.