• 제목/요약/키워드: cell surface antigen

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Transient and stable expression of hepatitis B surface antigen in tomato (Lycopersicon esculentum L.)

  • Srinivas, L.;Sunil Kumar, G.B.;Ganapathi, T.R.;Revathi, C.J.;Bapat, V.A.
    • Plant Biotechnology Reports
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    • 제2권1호
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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.

B 임파구의 분화 (B-cell Differentiation)

  • 양만표;이창우;권종국;장곡천독언
    • 한국임상수의학회지
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    • 제8권1호
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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.

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세포융합(細胞融合) 및 Hybridoma 세포작성(細胞作成)에 의한 항자돈백리(抗仔豚白痢) Monoclone항체(抗體)의 생산(生産) (Monoclonal Antibody Production against Piglet Diarrhea Agent (Enterotoxigenic E. coli) by Cell Fusion-Hybridoma Cell Technique)

  • 김우호;안수환;윤용덕
    • 대한수의학회지
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    • 제27권2호
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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.

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Analysis of the Major Histocompatibility Complex Class I Antigen Presentation Machinery in Human Lung Cancer

  • Kim, Hyun-Pyo;Jin, Mi-Rim;Kim, Ick-Young;Ahn, Byung-Yoon;Kang, Seong-Man;Choi, Eui-Ju;Kim, Joon;Kim, Ik-Hwan;Ahn, Kwang-Seog
    • Journal of Microbiology and Biotechnology
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    • 제9권3호
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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.

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Immunological Properties of Recombinant Hepatitis B Surface Antigen Expressed in Mammalian Cell(C127)

  • Lee, Young-Soo;Kim, Byong-Kak;Choi, Eung-Chil
    • Archives of Pharmacal Research
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    • 제21권5호
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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.

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Pre-surface antigen 지역과 poly(A) addition site가 포함된 B형 간염 표면항원 유전자의 재조합 (Cloning of the Hepatitis B Surface Antigen Containing Pre-surface Antigen Region and Poly(A) Addition Site)

  • Kim, Sang-Hae;Kim, Yong-Sok;Park, Mee-Young;Park, Hyune-Mo
    • 한국동물학회지
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    • 제28권3호
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    • pp.166-178
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    • 1985
  • 한국형 B형 간염바이러스(HBV) DNA의 표면항원 유전자를 포유동물 세포에서 발현시켜 항원의 검출과 유전자의 분자유전학적인 연구를 하기 위하여 pre-surface antigen 지역과 표면항원 유전자 그리고 poly(A) addition site가 포함된 DNA 조각을 simian virus 40(SV 40)의 DNA 복제 원점과 promoter가 포함된 유전자 운반체에 재조함 시켰다. 우선, HBV DNA가 들어있는 pHBV 107을 Bam HI으로 부분절단한뒤 self-ligation시켜 두 HBV DNA가 같은 방향으로 들어간 pHBVD 107을 만들었다. 이 plasmid를 Bgl II로 절단하였을때 pre-surface지역과 표면항원 유전자 그리고 poly(A) addition site가 함께 포함된 2.7 kb의 insert DNA 조각을 얻었다. 유전자 운반체로는 포유동물세포에서 복제할 수 있도록 하기 위하여 SV40의 DNA 복제 원점부위와 72 bp repeats(enhancer)가 포함된 pSVOE를 만든다음 이 vector의 Pvu II 절단자리에 Bam HI linker를 붙여 insert DNA가 vector의 SV40 late promoter지역 가까이에 들어갈 수 있도록 변형시킨 pSVOB를 만들었다. 이상과 같이 만들어진 pre-surface 지역-표면항원유전자-poly(A)-addition site가 포함된 2.7 kb DNA 절편을 pSVOB promoter 뒤의 Bam HI site에 삽입하여 재조합된 plasmid pSVBS를 얻었다. 예비실험으로 pSVBS를 T-antigen이 생산되는 COS cell에 이주시켰더니 $HB_sAg$가 발현됨을 보았다.

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인공 항원제시세포의 표면 분자의 특성 및 상호작용이 T 세포 활성화에 미치는 영향 (The effects of properties and interactions of surface molecules in antigen presenting cells on T cell activation)

  • 민영실;강윤중
    • 융합정보논문지
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    • 제10권6호
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    • pp.164-176
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    • 2020
  • 인체 적응 면역 반응을 일으키는데 중요한 항원 특이적 T 세포를 활용한 면역 세포 치료에서 T 세포를 체외에서 배양하고 클론 확장시키는 과정은 매우 섬세하고 복잡하여 조절하기가 쉽지 않아 T 세포의 활성화와 클론 확장을 유도하면서도 조절 및 취급이 용이한 인공 항원제시세포 개발의 필요성이 대두되고 있다. 인공 항원제시세포는 인체의 항원제시세포의 세포 표면 분자와 작용을 모방하게 되는데, 기본적인 신호 분자인 MHC-항원 복합체, 공동 자극 분자, 그리고 용해성 면역 조절 분자를 필수적으로 발현하여야 한다. 또한 T 세포가 항원과 접촉할 때, 이들 분자들이 잘 조직화되어 작용하는 것이 효과적인 T 세포 활성화에 중요하다. 본 논문에서는 여러 인공 항원제시세포 제작 방법과 세포 표면 분자들의 결합 방법과 물리적인 특성이 T 세포와의 상호작용에 중요함을 고찰하였으며, 효과적인 T 세포 활성화를 유도하며 면역세포치료에 적용 가능한 인공항원제세세포의 제작 방법을 살펴보았다.

Cell Surface Antigen Display for Neuronal Differentiation-Specific Tracking

  • Kim, Sang Chul;Lee, Eun-Hye;Yu, Ji Hea;Kim, Sang-Mi;Nam, Bae-Geun;Chung, Hee Yong;Kim, Yeon-Soo;Cho, Sung-Rae;Park, Chang-Hwan
    • Biomolecules & Therapeutics
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    • 제27권1호
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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.

Bacillus thuringiensis 항원들의 면역학적 분석 (Immunological Characterization of Bacillus thuringiensis Antigens)

  • 정재득;박정선;조영수;홍순복;이형환;조명환
    • 한국미생물·생명공학회지
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    • 제23권1호
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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.

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전자현미경 기법을 이용한 Herpes simplex 2형 바이러스 항원의 면역학적 분석 (Immunoelectron Microscopic Localization and Analysis of Herpes simplex Virus Type 2 Antigens)

  • 김천식;오명환
    • 미생물학회지
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    • 제40권1호
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    • pp.23-28
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    • 2004
  • 단순포진 바이러스 감염을 유발하는Herpes simplex2형 바이러스의 감염에 관여하는 항원들과 중화항체 생산을 유발하는 주요 항원들의 위치를 확인하였다. Vero cell에 감염하였을 때 48시간 동안 31, 43, 59, 69 kDa 바이러스 항원들이 지속적으로 발현되었으며, 감염된 쥐에서 생산한 항체와의 반응에서는 51 kDa 항원이 가장 강한 반응을 보였다. 면역전자현미경으로 위치를 확인한 결과 colloidal gold가 바이러스 표면에 발견되는 것으로 보아 이 항원이 바이러스 표면에 존재하고 있는 것으로 확인되었다. 형광현미경 분석은 이 항원들이 감염된 세포 내에서 전반적으로 발견되었고 특히 세포 표면에서 많이 발현되고 있었다.