• Parasites, Hosts and Diseases
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• 제51권1호
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• pp.69-74
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• 2013

Leishmania tropica is one of the causative agents of leishmaniasis in humans. Routes of infection have been reported to be an important variable for some species of Leishmania parasites. The role of this variable is not clear for L. tropica infection. The aim of this study was to explore the effects of route of L. tropica infection on the disease outcome and immunologic parameters in BALB/c mice. Two routes were used; subcutaneous in the footpad and intradermal in the ear. Mice were challenged by Leishmani major, after establishment of the L. tropica infection, to evaluate the level of protective immunity. Immune responses were assayed at week 1 and week 4 after challenge. The subcutaneous route in the footpad in comparison to the intradermal route in the ear induced significantly more protective immunity against L. major challenge, including higher delayed-type hypersensitivity responses, more rapid lesion resolution, lower parasite loads, and lower levels of IL-10. Our data showed that the route of infection in BALB/c model of L. tropica infection is an important variable and should be considered in developing an appropriate experimental model for L. tropica infections.

• 대한의생명과학회지
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• 제28권4호
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• pp.211-222
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• 2022

After more than two years of efforts to end the corona pandemic, a gradual recovery is starting in countries with high vaccination rates. Easing public health policies for a full-fledged post-corona era, such as lifting the mandatory use of outdoor mask and quarantine measures in entry have been considered in Korea. However, the continuous emergence of new variants of SARS-CoV-2 and limitations in vaccine efficacy still remain challenging. Fortunately, T cells and memory T cells, which are key components of adaptive immunity appear to contribute substantially in COVID-19 control. SARS-CoV-2 specific CD4⁺/CD8⁺ T cells are induced by natural infection or vaccination, and rapid induction and activation of T cells is mainly associated with viral clearance and attenuated clinical severity. In addition, T cell responses induced by recognition of a wide range of epitopes were minimally affected and conserved against the highly infectious subsets of omicron variants. Polyfunctional SARS-CoV-2 specific T cell memory including stem cell-like memory T cells were also developed in COVID-19 convalescent patients, suggesting long lasting protective T cell immunity. Thus, a robust T-cell immune response appears to serve as a reliable and long-term component of host protection in the context of reduced efficacy of humoral immunity and persistent mutations and/or immune escape.

• IMMUNE NETWORK
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• 제8권4호
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• pp.124-129
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• 2008

Background: The immunomodulatory effects of Korean mistletoe (Viscum album Coloratum) on the innate immune responses of eel (Anguilla japonica) were studied. Methods: Mistletoe, Freund’s complete adjuvant (FCA), or phosphate-buffered saline (PBS) as a control was injected into eel peritoneal cavities. Results: Nitroblue tetrazolium (NBT)-positive cells in the head kidney of eel were significantly augmented by the second day post-injection of mistletoe. Reactive oxygen intermediates (ROI) were more produced in mistletoe-injected fish kidney leucocytes than in FCA-injected ones. The level of lysozyme activity in the serum of fish 2 days after injection with mistletoe was also significantly higher than that in the serum of the control fish. The optimal concentration of mistletoe in inducing the highest serum lysozyme activity was revealed to 500${\mu}$g/200 g of fish. In phagocytic activity assay, mistletoe-sensitized eel kidney phagocytes captured more zymosan than did the control fish. Conclusion: Korean mistletoe appeared to be a good activator of the non-specific immune responses of eel.

• Environmental Analysis Health and Toxicology
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• 제4권1_2호
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• pp.1-10
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• 1989

Experiments were performed on mice to investigate the influences of doxycycine and ethanol on the immune responses. Doxycycline was injected intraperitoneally and ethanol was administered in the drinking water. Mice were sensitized and challenged with sheep red blood cells. Immune responses were evaluated by humoral immunity, cellular immunity, peripheral circulating white blood cell and phagocyte activity. Pathotoxicological influences were measured by serum protein and albumin. The weight of spleen, thymus and liver were measured. Doxycline and ethanol combined administration decreased the weight of thymus and spleen. Humoral and cellular immune response were reduced by doxycycline administration. Especially ethanol combined administration significantly reduced humoral and cellular immune response. Phagocyte activity was increased by ethanol combined administration and peripheral circulating white blood cell was significantly increased by ethanol adminstration. Ethanol combined administration decreased serum A/G ratio.

• 약학회지
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• 제46권1호
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• pp.52-57
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• 2002

Effects of the butanl fraction of Astragali Radix (BFAR) on the cellular and nonspecific immune responses were investigated in ICR mice. Mice were divided into 4 groups and BFAR at doses of 5, 25 and 125 mg/kg u ere administered orally to mice daily for 3 weeks, and the normal animals were given vehicle. The results of this study are summarized as follows; the relative weight of thymus was greatly increased by BFAR treatment, compared with that in mormal mice. However, the body weight gain was not affected. Delayed-type hypersensitivity (DTH) reaction to sheep red blood cells (SRBC) for cellular immunity was significantly enhanced by BFAR treatment, compared with those in normal mice. In these mice, BFAR also dose-dependently increased activities of phagocyte and natural killer (NK) cells as well as the number of leukocyte resulted from nonspecific immunity Thus, these results demonstrate that BFAF treatment results in a significant increase in both cellular and nonspecific immune responses to antigen in concentrations that enhance humoral immune function.

• Clinical and Experimental Pediatrics
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• 제48권11호
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• pp.1153-1161
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• 2005

As known by other name(natural immunity), the innate immune system comprises all those mechanisms for dealing with infection that are constitutive or built in, changing little with age or with experience of infection. Though in some ways less sophisticated than adaptive immunity, innate immunity should not belittled, since it has evidently protected thousands of species of invertebrates sufficiently to survive for up to 2 billion years. In the innate immune system, molecules of both cellular and humoral types are involved, corresponding to the need to recognize and dispose of different types of pathogen, to promote inflammatory responses and to interact to the adaptive immune system. A major features of innate immunity are the presence of the normal gut flora, complements, macrophages, dendritic cells, natural killer cells and many cytokines that can block the establishment of infection. Both phagocytic cells and complement system have tremendous potential for damaging host cells, but fortunately they are normally only triggered by foreign materials, and usually most of their destructive effects are focussed on the surface of these or in the safe environment of the phagolysosome. This article addreses the comprehensive mechanisms of the major components of the innate immune system to prevent the infection.

• Molecules and Cells
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• 제46권11호
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• pp.710-724
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• 2023

The plant defense responses to microbial infection are tightly regulated and integrated with the developmental program for optimal resources allocation. Notably, the defense-associated hormone salicylic acid (SA) acts as a promoter of flowering while several plant pathogens actively target the flowering signaling pathway to promote their virulence or dissemination. Ralstonia pseudosolanacearum inject tens of effectors in the host cells that collectively promote bacterial proliferation in plant tissues. Here, we characterized the function of the broadly conserved R. pseudosolanacearum effector RipL, through heterologous expression in Arabidopsis thaliana. RipL-expressing transgenic lines presented a delayed flowering, which correlated with a low expression of flowering regulator genes. Delayed flowering was also observed in Nicotiana benthamiana plants transiently expressing RipL. In parallel, RipL promoted plant susceptibility to virulent strains of Pseudomonas syringae in the effector-expressing lines or when delivered by the type III secretion system. Unexpectedly, SA accumulation and SA-dependent immune signaling were not significantly affected by RipL expression. Rather, the RNA-seq analysis of infected RipL-expressing lines revealed that the overall amplitude of the transcriptional response was dampened, suggesting that RipL could promote plant susceptibility in an SA-independent manner. Further elucidation of the molecular mechanisms underpinning RipL effect on flowering and immunity may reveal novel effector functions in host cells.

• BMB Reports
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• 제52권2호
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• pp.127-132
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• 2019

Cells must fine-tune their gene expression programs for optimal cellular activities in their natural growth conditions. Transcriptional memory, a unique transcriptional response, plays a pivotal role in faster reactivation of genes upon environmental changes, and is facilitated if genes were previously in an active state. Hyper-activation of gene expression by transcriptional memory is critical for cellular differentiation, development, and adaptation. TREM (Transcriptional REpression Memory), a distinct type of transcriptional memory, promoting hyper-repression of unnecessary genes, upon environmental changes has been recently reported. These two transcriptional responses may optimize specific gene expression patterns, in rapidly changing environments. Emerging evidence suggests that they are also critical for immune responses. In addition to memory B and T cells, innate immune cells are transcriptionally hyperactivated by restimulation, with the same or different pathogens known as trained immunity. In this review, we briefly summarize recent progress in chromatin-based regulation of transcriptional memory, and its potential role in immune responses.

• 식물병연구
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• 제21권3호
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• pp.161-179
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• 2015

식물은 다양한 병원성 미생물에 대하여 효과적인 방어 기제를 발전시켜 왔다. 최근 유전체와 다중 오믹스 기술의 발전은 우리에게 미생물 인자에 의한 식물 면역을 폭넓게 이해할 수 있는 단초를 제공해 주었다. 하지만 아직까지는 이러한 기술을 병 방제 전략에 이용한 적은 많지 않다. 그래서 본 리뷰에서 식물 면역의 기본 개념을 소개하고 최근 얻어진 결과들을 소개하였다. 덧붙여 이미 논문에서 발표된 진균, 세균, 바이러스 유래 결정인자에 의한 생물적 방제 가능한 방법에 대해 기술하였다. 특히 미생물 결정인자인 chitin, glucan, LPS/EPS, 미생물분자패턴, 항생제, 식물유사호르몬, AHLs, harpin, 비타민, 휘발성물질에 대한 결과를 자세하게 기술하였다. 이 리뷰를 통하여 많은 과학자들과 농민들이 미생물 결정인자 기반의 생물적 방제에 대한 지식이 폭넓어지고, 다양한 미생물 결정 인자가 앞으로 농업현장의 종합적인 병방제 전략의 하나로 자리매김하기를 바란다.

• IMMUNE NETWORK
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• 제5권3호
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• pp.137-143
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• 2005

Background: Millions of people in the world are suffering from atopic dermatitis (AD), which is a chronic inflammatory skin disease triggered by Th2 immune responses. The NC/Nga mouse is the most extensively studied animal model of AD. Like human AD, NC/Nga mice demonstrate increased levels of IgE, a hallmark of Th2 immune responses. Adaptive immunity cannot be generated without help of innate immunity. Especially natural killer T (NKT) cells and marginal zone B (MZB) cells have been known to play important roles in linking innate immunity to adaptive immunity. Methods: Through flow cytometric analysis and ELISA assay, we investigated whether these lymphocytes might be altered in number in NC/Nga mice. Results: Our data demonstrated that the number of NKT cells was reduced in NC/Nga mice and IFN${\gamma}$ production by NKT cells upon ${\alpha}-GalCer$ stimulation decreased to the levels of CD1d KO mice lacking in NKT cells. However, reduction of NKT cells in NC/Nga mice was not due to CD1d expression, which was normal in the thymus. Interestingly, there was a significant increase of $CD1d^{high}B220^+$ cells in the spleen of NC/Nga mice. Further, we confirmed that $CD1d^{high}B220^+$ cells are B cells, not dendritic cells. These $CD1d^{high}B220^+$ B cells show $IgM^{high}CD21^{high}CD23^{low}$, a characteristic phenotype of MZB cells. Conclusion: We provide the evidence that there are decreased activities of NKT cells and increased number of MZB cells in the NC/Nga mice. Our findings may thus explain why NC/Nga mice are susceptible to AD.