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The Study of MHC class I Restricted CD8+ T Cell Mediated Immune Responses against Mycobacterium tuberculosis Infection: Evidence of M. tuberculosis S pecific CD8+ T Cells in TB Patients and PPD+ Healthy Individuals (MHC class I 분자들에 의해 제시되는 Epitope을 인지하는 CD8+ T 림프구의 결핵균 감염에 대한 면역반응의 연구: 결핵 환자와 PPD+ 건강개체에 존재하는 결핵균 항원에 특정한 CD8+ T세포)

  • Cho, Jang-Eun;Lee, Kyung Wha;Park, Seung Kyu;Cheon, Seon-Hee;Cho, Sang-Nae;Cho, Sungae
    • IMMUNE NETWORK
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    • v.3 no.3
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    • pp.235-241
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    • 2003

  • Background: The protective immunity against tuberculosis (TB) involves both CD4+ T cells and CD8+ T cells. In our previous study, we defined four Mycobacterium tuberculosis derived peptide epitopes specific for HLA-$A^*0201$ restricted CD8+ T cells ($ThyA_{30-38}$, $RpoB_{127-135}$, $85B_{15-23}$, $PstA1_{75-83}$). In this study, we investigated the immune responses induced by these peptide specific CD8+ T cells in latently and chronically infected people with TB. Methods: We characterized these peptide specific CD8+ T cell population present in PBMC of both TB patients and PPD+healthy people using IFN-${\gamma}$elispot assay, intracellular staining and HLA-A2 dimer staining. Results: The frequency of peptide specific CD8+ T cell was in the range of 1 to 25 in $1.7{\times}10^5$ PBMC based on ex vivo IFN-${\gamma}$ elispot assay, demonstrating that these peptide specific CD8+ T cell responses are induced in both TB patients and PPD+ people. Short term cell lines (STCL) specific for these peptides proliferated in vitro and secreted IFN-${\gamma}$ upon antigenic stimulation in PPD+ donors. Lastly, HLA-$A^*0201$ dimer assays indicated that $PstA1_{75-83}$ specific CD8+ T cell population in PPD+ healthy donors is heterogeneous since approximately 25~33% of $PstA1_{75-83}$ specific CD8+ T cell population in PPD+ healthy donors produced IFN-${\gamma}$ upon peptide stimulation. Conclusion: Our results suggest that MHC class I restricted CD8+ T cell mediated immune responses to M. tuberculosis infection are induced in both TB patients and PPD + people; however, the CD8+ T cell population is functionally heterogeneous.

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Effects of Non-Uniform Traffic Distribution on the Capacity of Reverse Link CDMA System

  • Cho, Choon-Geun;Ann, Jong-Hoon;Tchah, Kyun-Hyon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.12A
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    • pp.1828-1835
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    • 2000

  • In this paper, we analyzed the other-cell interference characteristics for various non-uniform traffic distributions and their effects on the capacity of multi-cell CDMA system. We consider three different traffic distributions, i.e., linear, exponential and Gaussian traffic distribution with distribution parameters. Changing the distribution parameter, we can obtain the center-focused distributions or uniform distributions for each model. From the results of other-cell interference calculation we can see that the other-cell interference decreases, as the user concentrates on the base station. Also using frequency reuse efficiency indicating the capacity reduction of a multi-cell system when compared to a single cell system, we evaluate the effect of traffic distribution on the reverse link CDMA capacity. For linear case, the capacity of multi-cell system is reduced to 0.637∼0.867 times that of single cell system. On the other hand, for both exponential and Gaussian cases, the capacity under a multi-cell environment is equal to 70∼100% of that under a single cell. Therefore, we conclude that the average capacity of multi-cell CDMA system are increased when users are likely to be at near the cell base station due to reduced total other-cell interference and decreased when users exist at near the cell edge regardless of traffic distribution models.

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Cell-cell Adhesion of Jurkat T Cells Induced by CD29 and CD98 Activation and its Application (CD29 및 CD98 활성 매개에 의한 Jurkat T 세포의 유착과 그 활용)

  • Kim, Byung-Hun;Cho, Jae-Youl
    • YAKHAK HOEJI
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    • v.53 no.3
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    • pp.119-124
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    • 2009

  • Cell-cell adhesion managed by various adhesion molecules plays an important role in regulating functional activation of cells. This event mediates attachment of inflammatory cells to endothelial cells, interaction of antigen-presenting cells with T cells and metastatic adherence of cancer cells to epithelial tissue cells. Therefore, this cellular response is considered as one of therapeutic target to treat various cancers and inflammatory diseases. To develop proper model for evaluation of functional activation of adhesion molecules, the ability of U937 and Jurkat T cells responsive to various adhesion inducers such as phorbal-12-myristate-13-acetate (PMA), staurosporin and monoclonal antibodies to CD29, CD43 and CD98 was investigated using quantitative cell-cell adhesion assay. U937 cells made more cell-cell clusters by the treatment of antibodies to CD29 and CD43 than Jurkat T cells, while Jurkat T cells exhibited increased cell-cell adhesion ability in CD98 antibody treatment. In agreement, the surface levels of CD29 and CD98 were highly observed in U937 and Jurkat T cells, respectively. Therefore, our data suggest that Jurkat T and U937 cells can be used for model system to evaluate functional activation of adhesion molecules such as CD29 and CD98.

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