• IMMUNE NETWORK
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• v.15 no.4
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• pp.199-205
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• 2015

T-bet is a critical transcription factor that regulates differentiation of Th1 cells from $CD4^+$ precursor cells. Since T-bet directly binds to the promoter of the IFN-${\gamma}$ gene and activates its transcription, T-bet deficiency impairs IFN-${\gamma}$ production in Th1 cells. Interestingly, T-bet-deficient Th cells also display substantially augmented the production of IL-2, a T cell growth factor. Exogenous expression of T-bet in T-bet deficient Th cells rescued the IFN-${\gamma}$ production and suppressed IL-2 expression. IFN-${\gamma}$ and IL-2 reciprocally regulate Th cell proliferation following TCR stimulation. Therefore, we examined the effect of T-bet on Th cell proliferation and found that T-bet deficiency significantly enhanced Th cell proliferation under non-skewing, Th1-skewing, and Th2-skewing conditions. By using IFN-${\gamma}$-null mice to eliminate the anti-proliferative effect of IFN-${\gamma}$, T-bet deficiency still enhanced Th cell proliferation under both Th1- and Th2-skewing conditions. Since the anti-proliferative activity of T-bet may be influenced by IL-2 suppression in Th cells, we examined whether T-bet modulates IL-2-independent cell proliferation in a non-T cell population. We demonstrated that T-bet expression induced by ecdysone treatment in human embryonic kidney (HEK) cells increased IFN-${\gamma}$ promoter activity in a dose dependent manner, and sustained T-bet expression considerably decreased cell proliferation in HEK cells. Although the molecular mechanisms underlying anti-proliferative activity of T-bet remain to be elucidated, T-bet may directly suppress cell proliferation in an IFN-${\gamma}$- or an IL-2-independent manner.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.4
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• pp.995-1000
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• 2004

This study was purposed to investigate the effect of Gamgung-tang(GGT) on immune responses induced by glucocorticoid in mice. GGT solution was treated by intraperitoneal injection for 7 days after glucocorticoid treatment(80㎎/㎏). And then B and T cell proliferation and cytolytic activity of natural killer(NK) cells were measured. There was 25% inhibition in B cell proliferation with treatment of glucocorticoid. However, B cell proliferation was not influenced by GGT treatment. T cell proliferation was also inhibited by 18.4% with treatment of glucocorticoid. On the other hand, T cell proliferation was increased dose-dependent manner in GGT treated group. Furthermore in purified T cell, the proliferation was furtherly increased than non-purified T cell. At concentration of 18㎎/mouse GGT, purified T cell proliferation was increase to above level of normal group. The cytotoxic activity of NK cell was decreased by 35.3% with treatment of glucocorticoid. In GGT treated group, the cytotoxic activity of NK cell was increased to the normal level. In purified NK cell, the cytolytic activity of NK cell was further increased than non-purifed NK cell. These results suggest that GGT may proliferate T cell that is suppressed by glucocorticoid, and activate NK cell activity.

• Parasites, Hosts and Diseases
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• v.54 no.2
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• pp.147-154
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• 2016

Toxoplasma gondii infection induces alteration of the host cell cycle and cell proliferation. These changes are not only seen in directly invaded host cells but also in neighboring cells. We tried to identify whether this alteration can be mediated by exosomes secreted by T. gondii-infected host cells. L6 cells, a rat myoblast cell line, and RH strain of T. gondii were selected for this study. L6 cells were infected with or without T. gondii to isolate exosomes. The cellular growth patterns were identified by cell counting with trypan blue under confocal microscopy, and cell cycle changes were investigated by flow cytometry. L6 cells infected with T. gondii showed decreased proliferation compared to uninfected L6 cells and revealed a tendency to stay at S or G2/M cell phase. The treatment of exosomes isolated from T. gondii-infected cells showed attenuation of cell proliferation and slight enhancement of S phase in L6 cells. The cell cycle alteration was not as obvious as reduction of the cell proliferation by the exosome treatment. These changes were transient and disappeared at 48 hr after the exosome treatment. Microarray analysis and web-based tools indicated that various exosomal miRNAs were crucial for the regulation of target genes related to cell proliferation. Collectively, our study demonstrated that the exosomes originating from T. gondii could change the host cell proliferation and alter the host cell cycle.

• Korean Journal of Pharmacognosy
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• v.35 no.4 s.139
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• pp.330-337
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• 2004

Based on the traditional application of Carthamus tinctorious L. (CF) as a component of Korean medicinal decoctions, in the present study, we investigated in vitro an immunomodulatory activity of water extract of CF(WECF). Water extract of CF significantly increased the in vitro proliferative responses of spleen cells (SPC). However, addition of WECF during anti-CD3 activation resulted in a significant decrease in SPC proliferation. Flow cytometric analysis showed that WECF addition chanced T and B cell frequencies in anti-CD3-activated spleen cell populations. Using purified cells, it was revealed that WECF is mitogenic to B cells but rather inhibitory to T cell Proliferation. Upon anti-CD3 stimulation, high concentration (1 mg/ml) of WECF significantly inhibited T cell proliferation until day 2 of stimulation. At day 3, anti-CD3-activated cells exposed to WECF recovered their proliferation to the level comparable to control. Although B cell proliferation was also inhibited in proliferation at day 1, it recovered sooner and then was rather augmented by WECF at day 3. These data indicate that WECF down-regulates lymphocyte proliferation at early phase of activation but T cells are more vulnerable than B cells to WECF, However, CD4+ and CD8+ T cells did not differ in WECF-mediated immunotoxicity. Data of propidium iodide (PI) staining showed that WECF accelerates activated T cell, but not B cell, apoptosis and WECF concurrently inhibited cytokine production of activated T cells. Taken together, WECF exhibits B cell mitogenic activity and differential toxicity more pronounced to T cells, suggesting a possible in vivo application of WECF for specific control of T cells without alteration of B cell activity.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.805-818
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• 1997

Immune responses of periodontal tissue may be regulated by products of sensory afferent nerve endings such as neuropeptides. Substance P(SP), a tachykinin neuropeptide, has been previously reported to stimulate the activities of T lymphocyte. Therefore, I examined the role of SP in IL-2 production and cell proliferation by using a homogeneous line of T lymphocytes(Jurkat and HuT78). Cell proliferation rate was determined by [$^3H$]-thymidine incorporation test, and IL-2 was quantitated by the growth rate of CD4+ IL-2-dependent T lymphocyte line CTLL-2. SP stimulated cell proliferation of T lymphocytes at the concentration of $10^{-12}$ and $10^{-8}$M in a biphasic bell-shape dose-dependent manner. However, SP alone did not induce IL-2 release at the concentration range of $10^{-6}$ to $10^{-14}$M. The upregulation of IL-2 release was observed when $10^{-12}$M SP was applied together with mitogens such as Con A or PHA+PMA on T cell lines, especially on Jurkat. Con A or PHA+PMA demonstrated to increase the rate of cell proliferation of Jurkat, which had shown to produce much amount of IL-2 indicating that mitogen-induced cell proliferation might be partially influenced by released IL-2. It was concluded that regulatory effects of SP on the immune/inflammatory response could be mediated through the costimulatory upregulation of IL-2 production and increase of cell proliferation of T lymphocyte.

• Journal of Nutrition and Health
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• v.36 no.7
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• pp.661-666
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• 2003

The study was designed to compare the anti-carcinogenic effect of conjugated linoleic acid (CLA) isomers on colon carcinogenesis in 1,2-dimethylhydrazine (DMH)-treated rats by determining the levels of apoptosis, cell proliferation, eicosanoids and 1,2-diacylglycerol (DAG) in colonic mucosa. Sixty male Sprague Dawley rats were randomly divided into 3 groups depending on the types of CLA isomers, i.e. BT group (no CLA contained), CLA-C group (cis-9, trans11 isomer contained), and CLA- T group (trans-10, cis-12 isomer contained). The experimental diet was composed of protein at 20%, carbohydrate at 56.2%, and fat at 14.5% including 0.8% CLA isomers by weight. The experimental diet was fed for 14 weeks with the initiation of intramuscular injection of DMH, which was injected twice a week for 6 weeks to give total dose of l80mg per kg body weight. Two CLA isomers (c9t11 and t10c12) significantly increased the relative percentage of apoptosis but reduced cell proliferation in mucosal cell and also the levels of PGE$_2$, TXB$_2$, and DAG in colonic mucosa. However, there was no significant differences in anti-carcinogenic effect between c9t11 isomer and t10c12 isomer. Overall, colon carcinogenesis could be significantly inhibited by CLA isomers by increasing apoptosis and reducing cell proliferation, the levels of eicosanoids and DAG in colonic mucosa.

• Journal of Periodontal and Implant Science
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• v.23 no.3
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• pp.454-460
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• 1993

Abnormalities of the T cell subsets have been detected in the immunologically mediated disease sites such as periodontal lesions which are attributable to the regulatory effect of cell differentiation and specific chemokinetic effect of various cytokines. Macrophage Inflammatory protein$(MIP)-1{\alpha}$ and gammain terferon$({\gamma}-IFN)$ serve as important immunoregulatory molecules through which growth and differentiation of specific T cell subsets are known to be negatively regulated. Murine cytolytic T cell line CTLL-2 were used to perform the [$^3H$]-thymidine incorporation test, by which we obtained more comprehensive view in regulatory actions of cytokines on the T cell subset proliferation. 1. $rMIP-{\alpha}$(200ng/ml) and $r{\gamma}-IFN$(100U/ml) appreared to suppress the proliferation rate to CTLL-2 by 74 and 86% respectively, and the suppressive action of two cytokines were synergisic. 2. Culture supernatant of anti-CD3 mAb-stimulated mouse splenocyte enhanced the proliferation rate of CTLL-2 up to 10-fold with dose-dependent manner. However, culture supernatant of unstimulated splenocyte showed only 2-fold increase in the proliferation rate. 3. CTLL-2 cell proliferation was strictly IL-2 dependent.

• Natural Product Sciences
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• v.13 no.2
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• pp.123-127
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• 2007

We investigated effect of small black soybean fraction (SBSF) T cell-mediated responses for tumor surveillance and proliferation in leukemia cells in vitro. Each SBSF butanol fraction (SBSFBu) and SBSF chloroform fraction (SBSFCh) was administered p.o. once a day far 21 days in BALB/c mice and then levels of serum cytokines and subpopulation of lymphocytes were measured. Moreover, SBSF fraction was treated into the cultured various cell lines for proliferation in leukemia cell lines, NO production by RAW264.7 cells, and expression of p53 gene in U937 leukemia cells. These results showed that SBSFBu increased levels of serum IL-4but not IL-2 and IFN-${\gamma}$, and increased expression of CD4$^+$ T cells and CD8$^+$ T cells in splenocytes in vivo, while SBSFCh increased levels of serum IL-2 and IFN-${\gamma}$ but decreased IL-4, and increased CD8$^+$ T cells but not CD4$^+$ T cells. Moreover, both of SBSFBu and SBSFCh inhibited proliferation of HL60, U937, and L1210 leukemia cell lines in a dose-dependent manner, up-regulated NO production by RAW264.7 cells in a dose-dependent manner, and enhanced expression of p53 gene in U937 leukemia cells. Our findings indicate that SBSFBu and SBSFCh may enhance T cell-dependent immune responses, and that both of SBSFBu and SBSFCh may inhibit proliferation of leukemia cells by up-regulation of NO production and expression of p53 gene.

• Journal of Animal Science and Technology
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• v.55 no.1
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• pp.19-23
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• 2013

The current study was carried out to determine the effects of Kohlrabi (Brassica oleracea var. gongylodes) on proliferation and differentiation of pig preadipocytes and $_3T_3-L_1$ cells. Pig preadipocytes were isolated from the backfat of the new-born pigs. Twenty-four hours after seeding, the cells were washed with DMEM/F-12 (designated day 0). To measure the cell proliferation, the cells were treated with 25 ng/ml and 100 ng/ml ethanol extracts of Kohlrabi (peel and flesh) for two days (day 0 ~ 2). To measure differentiation, the cells were treated with Kohlrabi for two days (day 0 ~ 2) and cell differentiation was measured on day 6. Twenty-five ng/ml and 100 ng/ml of Kohlrabi peel decreased proliferation of pig preadipocytes by 4.59% and 17.7%, respectively, compared with the control and Kohlrabi flesh by 11.4% and 19.2%, respectively. However, Kohlrabi did not inhibit cell differentiation. To measure the effects of Kohlrabi on proliferation and differentiation of $_3T_3-L_1$ cells, the cells were treated with Kohlrabi for two days in culture, like pig preadipocytes. Kohlrabi (both peel and flesh) did not show any effects on cell proliferation and differentiation. In summary, the results of the current study showed that Kohlrabi decreased proliferation of pig preadipocytes, but no inhibitory effects on differentiation of the cells. Kohlrabi had no effects on proliferation and differentiation of $_3T_3-L_1$ cells.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.1
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• pp.153-163
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• 1996

Macrophage inflammatory protein $(MIP)-1{\alpha}$ is a cytokine which produces wide range of bioactivities such as proinflammatory, immunomodulatory, and hematopoietic modulatory actions. To determine whether $MIP-1{\alpha}$ acts as a negative regulator on the functions of lymphocyte, $[^3H]$-thymidine incorporation test and flow cytometric analysis were performed by using human tonsil T cell, human peripheral blood T cell, and murine cytolytic T lymphocyte (CTL) line CTLL-2, The results were as follow. 1. When human tonsil T lymphocytes were stimulated with anti-CD3 monoclonal antibody (mAb), rate of T cell proliferation was about four times increased. 200ng/ml of $MIP-1{\alpha}$ inhibited anti-CD3 mAb-mediated T cell growth as much as 60% (P<0.05). 2. The suppression of human peripheral T cell proliferation produced by $MIP-1{\alpha}$ was dramatic, but variable among T cells derived from different individuals $(40%{\sim}90%)$. 3. $MIP-1{\alpha}$inhibited the proliferation of murine CTL line CTLL-2 as much as 75%(P<0.001). 4. When the $MIP-1{\alpha}$ was added to human peripheral T cell, cell proporation of $CD4^+$ helper T cell and $CD8^+$ CTL were not noticeably affected. The expression level of CD4, not of Cd8, however, was down regulated by $MIP-1{\alpha}$ treatment $(27%{\sim}82%)$.