• Plant Biotechnology Reports
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• v.2 no.1
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• pp.1-6
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• 2008

Cotyledonary leaves of tomato cv. Megha were transformed with the hepatitis B virus 's' gene, which encodes surface antigen. Six plant expression cassettes (pHBS, pHER, pEFEHBS, pEFEHER, pSHER and pEFESHER) were used to assay the possible expression levels by agroinfiltration. The maximum transient expression level of 489.5 ng/g D.W. was noted in pEFEHER-infiltrated cotyledonary leaves. Transgenic tomato plants with pEFEHBS and pEFEHER expression cassettes were regenerated and characterized by molecular analysis. The expression of the antigen in the fruits was confirmed by RT-PCR and ELISA analysis. This is the first report on the expression of hepatitis B surface antigen in tomato.

• Journal of Veterinary Clinics
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• v.8 no.1
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• pp.1-10
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• 1991

The B-lymphocyte differentiation from committed B-cell progenitors to antibody-secreting cells was discussed. B-cell progenitors derived from hematopoietic stem cells undergo the rearrangement of immunoglobulin(Ig) gene. The earliest cells as B-cell precursors have cytoplasmic Is(${\mu}$ chain). The entire Is molecule is expressed on the surface after synthesis of L chain. The resting B cells(Go stage) stimulated by binding antigen via Ig-receptors are activated(G$_1$ stage) and followed by proliferation(S stage), coupled with further selection(affinity maturation. class switch). The production of antibody against a particular antigen depends on the activation of B cells with surface Is capable of reacting with that antigen. This process does not occur in isolation but is controlled by helper and suppressor T cells and antigen presenting cells(APC). The mechanism of T cell-dependent B-cell response for production of antibody is largely explained by the cell to cell cooperation and soluble helper factors of T cells. 1) The antigen specific B cells and helper T cells are linked by Is-receptors, leading to the delivery of helper signals to the B cells. 2) Helper T cells recognize the processed antigen-derived peptides with the MHC class II molecules(la antigen) and is stimulated to secrete B-cell proliferation and differentiation factors which activate B cells of different antigenic specificity. The two models are shown currently 1) At low antigen concentration, only the antigen-specific B cell binds antigen and presents antigen-derived peptides with la molecules to helper T cells, which are stimulated to secrete cytokines(IL-4, IL-5, etc.) and 2) At high antigen concentration, antigen-derived peptides are presented by specific B cells, by B cells that endocytose the antigens, as well as by APC Cytokines secreted from helper T cells also lead to the activation of B cells and even bystander B cells in the on- vironmment and differentiate them into antibody-secreting plasma cells.

• Korean Journal of Veterinary Research
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• v.27 no.2
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• pp.259-267
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• 1987

Enterotoxigenic E. coli (ETEC) cause an acute diarrhea (white scour) in both animals and humans. The disease process initially involves the adherence and colonization of the mucosal surface of the small intestine, followed by the elaboration of a heat-labile enterotoxin (LT) and/or heat-stable enterotoxin (ST). Intestinal adherence or colonization by ETEC is generally mediated by a specific surface-associated pilus (fimbrial) antigen that endows the bacteria with the capacity to adhere to epitherial cell surface. Fourteen monoclonal antibodies (MAbs) directed against pili antigens of ETEC were obtained by cell fusion/hybridoma technique. They were characterized by indirect immunofluorescence assay (IFA), and divided into four groups: specific to K99 antigen (group 1), cross-reactive with K99 and F41 antigens (group 2), specific to K88 antigen (group 3) and specific to 987P and K88 antigens (group 4), respectively. These MAbs demonstrated the distinct pili (K) antigens on the surface of ETEC by IFA, and could be utilized as diagnostic reagent for the identification of ETEC. When eighty-seven field isolates of E. coli from piglet with diarrhea were tested by group 3 MAb, fourty-two strains (48.3%) has K88 pilus antigen suggesting that this is one of the major pilus antigen of ETEC present in fifeld.

• Journal of Microbiology and Biotechnology
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• v.9 no.3
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• pp.346-351
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• 1999

Tumor cells may alter the expression of proteins involved in antigen processing and presentation, allowing them to avoid recognition and elimination by cytotoxic T cells. In order to investigate whether the major histocompatibility complex (MHC) class I-mediated antigen processing machinery is preserved in human lung cancer cell lines, we examined the expression of multiple components of the MHC class I antigen processing pathway, including transporter associated with antigen processing (TAP), $\beta_2$-microglobulin, MHC class I molecules, and chaperones which have not been previously examined in this context. Row cytometry analysis showed that the cell surface expression of MHC class I molecules was downregulated in all of the cell lines. While some cell lines showed no detectable expression of MHC class I molecules, pulse-chase experiments showed that MHC class I molecules were synthesized in the other cell lines but not transported from the endoplasmic reticulum to the cell surface. Low or nondetectable levels of TAP1 and/or TAP2 expression were demonstrated by Western blot analysis in all of the cell lines, representing a variety of lung tissue types. In some cases, this was accompanied by loss of tapasin expression. Our findings suggest that downregulation of antigen processing may be one of the strategies used by tumors to escape immune surveillance. This study provides further information for designing the potential therapeutic applications such as immunotherapy and gene therapy against cancers.

• Archives of Pharmacal Research
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• v.21 no.5
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• pp.543-548
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• 1998

We examined the immunological properties of the recombinant hepatitis B surface antigen (r-HBsAg) which was expressed in mammalian cell (C127). The cross-immunity of r-HBsAg and plasma-derived hepatitis B surface antigen (p-HBsAg) were tested using Western blotting and ELISA with guinea pig polyclonal antibody and naturally infected human-derived antibody and the both antigens show the same results in their response pattern and intensity, which indicate they have a good cross-immunity. from the measurement of $ED_{50}$ after formalin- or heat-inactivation, both r-HBsAg and p-HBsAg and p-HBsAg showed $ED_{50}$ of 0.2-0.3 in formalin-inactivaton, while r-HBsAg was 0.05-0.09 and p-HBsAg was 0.03-0.07 in heat-inactivation, which means heat-inactivation method is 3-4 times superior in immunogenicity. In the immunopersistency test performed in guinea pig for the period of 3 months with two different adjuvants, antibody titer was 34.2 with muramyl dipeptide adjuvant, which was 1.8 times greater than the antibody titer of 18.9 with $AIPO_{4}$ adjuvant. the mutagenicity of r-HBsAg has the same cross-immunity with p-HBsAg, and heat-inactivation method and muramyl dipeptide adjuvant allow development of r-HBsAg vaccine with excellent immunogenicity.

• The Korean Journal of Zoology
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• v.28 no.3
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• pp.166-178
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• 1985

In order to express hepatitis B surface antigen $(HB_sAg)$ containing pre-surface antigen region in mammalian calls, 2.7 kb DNA fragment containing pre-surface region-$HB_sAg$ gene poly(A) addition site of HBV genome was cloned into simian virus 40(SV 40) based chimeric vector pSVOB. 2.7 kb DNA fragment was derived from pHBVD 107 containing tandem copies of the HBV genome in a head-to-tail arrangement by Bgl II digestion. Construction of the vector pSVOE involved the incorporation of SV40 sequences spanning the viral origin of replication and 72 bp repeats (enhancer) into a pBR 322 derivative lacking sequences which inhibit replication in mammalian cells. Bam HI linker was inserted at the Pvu II site in the proximity of SV40 late promoter of pSVOE and named as pSVOB. To construct the recombinant plasmid pSVBS, pHBVD 107 was digested with Bgl II to isolate 2.7kb DNA fragment and the fragment was ligated into the Bam HI site of pSVOB by ligation. Preliminary result showed that the recombinant plasmid pSVBS produced $HB_sAg$ in the monkey cell producing large T antigen (COS cell).

• Journal of Convergence for Information Technology
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• v.10 no.6
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• pp.164-176
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• 2020

Efficient production of antigen specific cytotoxic T cells is critical for appropriate adoptive immune response. In vitro culture and expansion of human T lymphocyte clones are very sophisticated and subtle procedure in immune cell therapy and hard to control. Therefore, many groups devoted their efforts to manipulate artificial antigen presenting cells (aAPCs) that can induce T cell activation and clonal expansion. To mimicking of natural antigen-presenting cells, aAPCs encompass basic signal molecules required for T cell activation: MHC:antigen complexes, co-stimulatory molecules and soluble immune modulating molecules. Orchestrated organization of these molecules is important for efficient T cell activation. Here, we discuss how those molecules have been incorporated in several aAPC models, but also how physical properties od aAPC are important for interaction with T cells.

• Biomolecules & Therapeutics
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• v.27 no.1
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• pp.78-84
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• 2019

Cell therapeutic agents for treating degenerative brain diseases using neural stem cells are actively being developed. However, few systems have been developed to monitor in real time whether the transplanted neural stem cells are actually differentiated into neurons. Therefore, it is necessary to develop a technology capable of specifically monitoring neuronal differentiation in vivo. In this study, we established a system that expresses cell membrane-targeting red fluorescent protein under control of the Synapsin promoter in order to specifically monitor differentiation from neural stem cells into neurons. In order to overcome the weak expression level of the tissue-specific promoter system, the partial 5' UTR sequence of Creb was added for efficient expression of the cell surface-specific antigen. This system was able to track functional neuronal differentiation of neural stem cells transplanted in vivo, which will help improve stem cell therapies.

• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.110-117
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• 1995

This study was carried out to immunologically characterize Bacillus thuringiensis (B.t) antigens. Protein patterns of ultrasonicated- antigens of B. thuringiensis subspecies using SDS- PAGE revealed marked similarities among all the strains analyzed except for the difference between quantative variations of bands and some protein antigens. The comparison of the protein patterns showed that the protein antigen of 45 kilodalton (kd) was common in 11 strains and that the difference between B. thuringiensis subsp. canadensis and galleriae was noticed in quantative variations of bands despite of ambiguous serogrouping, suggesting a useful method for identification. All strains examined showed similar antigenic patterns in SDS-PAGE, while immunodominant bands differed in antigenic reactivity in western blot using polyclonal antibodies. Polyclonal antibody to B. thuringiensis subsp. thuringiensis and israelensis in indirect immunofluorescence assay reacted with flagella and cell surface antigens. The present study indicates that SDS-PAGE and western blot analysis may be used as tools for differentiation and identification of B. thuringiensis subspecies.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.23-28
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• 2004

Antigenic analysis of Herpes simplex type 2 virus was performed and its major antigen was localized using an immunoelectron microscopy. Antigens of 32, 43, 59 and 69 kDa were constantly expressed during the course of infection for 48 hr in the infected Vero cell. An antigen of 51 kDa was turned out to be the major one in inducing a immune response in Western-blot analysis. The 51 kDa antigen was localized on the surface of HSV-2 by immunoelectron microscopy using colloidal golds and anti-HSV 2 polyc1onal antibody. Immunofluorescence assay indicated that viral antigens were found throughout the infected cell and, especially, on the surface of the cell.