• IMMUNE NETWORK
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• 제4권4호
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• pp.205-215
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• 2004

In the early host defense system, effector function of natural killer (NK) cells results in natural killing against target cells such as microbe-infected, malignant, and certain allogenic cells without prior stimulation. NK cell cytotoxicity is selectively regulated by homeostatic prevalence between a repertoire of both activating and inhibitory receptors, and the discrimination of untransformed cells is achieved by recognition of major histocompatibility complex (MHC) class I alleles through inhibitory signals. Although it is well known that the bipotential T/NK progenitors are derived from the common precusor, functional mechanisms in terms of the development of NK cells remain to be further investigated. NK cells are mainly involved in innate immunity, but recent studies have been reported that they also play a critical role in adaptive immune responses through interaction with dendritic cells (DC). This interaction will provide effector functions and development of NK cells, and elucidation of its precise mechanism may lead to therapeutic strategies for effective treatment of several immune diseases.

• 생명과학회지
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• 제18권6호
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• pp.891-896
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• 2008

The function of mast cells as effector cells in allergy has been extensively studied. Mast cells activated through high affinity IgE-receptor ($Fc{\varepsilon}RI$) release diverse mediators, and lead to smooth muscle constriction, vasodilation, increase of vascular permeability, leukocyte recruitment and activation, mucus secretion, and tissue proliferation and remodeling. However, various other immunological and non-immunological signals can lead to the activation of mast cells. In resent years, mast cells have been identified to be involved in a complex range of immune functions. Mast cells can be important as key players in the regulation of innate as well as adapted immune responses, and may influence the development of allergy, autoimmune disorder and peripheral tolerance. This review summarizes the recent advances in the understanding of effector functions of mast cells in immune responses.

• BMB Reports
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• 제38권2호
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• pp.128-150
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• 2005

Invertebrate animals, which lack adaptive immune systems, have developed other systems of biological host defense, so called innate immunity, that respond to common antigens on the cell surfaces of potential pathogens. During the past two decades, the molecular structures and functions of various defense components that participated in innate immune systems have been established in Arthropoda, such as, insects, the horseshoe crab, freshwater crayfish, and the protochordata ascidian. These defense molecules include phenoloxidases, clotting factors, complement factors, lectins, protease inhibitors, antimicrobial peptides, Toll receptors, and other humoral factors found mainly in hemolymph plasma and hemocytes. These components, which together compose the innate immune system, defend invertebrate from invading bacterial, fungal, and viral pathogens. This review describes the present status of our knowledge concerning such defensive molecules in invertebrates.

• 농업과학연구
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• 제35권2호
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• pp.177-182
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• 2008

Type I Interferons (IFNs) are potent antiviral cytokines that modulate both innate immunity and adaptive immunity. Type I IFNs are immediately induced by viral infection, and stimulate production of a broad range of gene products such as double-stranded RNA-activated protein kinase (PKR), 2' 5'-oligoadenylate synthetase (OAS)/RNaseL and Mx GTPases. These proteins inhibit viral replication in host cells. Type I IFNs, in turn, lead to antiviral state at early phase of viral infection. We provide an overview of the knowledge of IFN-inducible antiviral proteins conserved in vertebrates.

• The Korean Journal of Medicine
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• 제99권4호
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• pp.169-179
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• 2024

In recent years, the incidence and prevalence of non-tuberculous mycobacteria lung disease (NTM-LD) has been increasing worldwide. In Korea, Mycobacterium avium complex (MAC) and Mycobacterium abscessus complex account for most common cause of NTM-LD. It is essential to elucidate the pathophysiology of NTM-LD. The pathophysiology of NTM-LD has not been fully understood, however, it can be divided into bacterial and host-side factor. Among the host factor, innate immunity plays an essential role in the initial host immune response against intracellular non-tuberculous mycobacteria (NTM), and adaptive immunity also has a role. However, the role of these immunity in mycobacterial disease has been mainly studied in tuberculosis, but studies on its role in NTM are limited. In this review, I focus on NTM innate and adaptive immunity, the role of macrophages and neutrophils, and host interaction in NTM infection.

• Toxicological Research
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• 제23권2호
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• pp.97-105
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• 2007

Toll-like receptors (TLRs) playa crucial role in initiating and regulating innate and adaptive immune responses by detecting invading microbial pathogens. TLRs can also respond to non-microbial molecules derived from damaged tissue. Accumulating evidence suggests that deregulation of TLRs results in the dysfunction of immune system and ultimately increases the risk of many immune and inflammatory diseases including infectious diseases, allergy, and autoimmune diseases. Therefore, understanding how the immune system is controlled by TLRs will provide new insight to find the way to prevent or treat infectious diseases and immune disorders.

• 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.

• IMMUNE NETWORK
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• 제21권1호
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• pp.1.1-1.16
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• 2021

The emergence of a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has become a significant health concern worldwide. Undoubtedly, a better understanding of the innate and adaptive immune responses against SARS-CoV-2 and its relationship with the coronavirus disease 2019 (COVID-19) pathogenesis will be the sole basis for developing and applying therapeutics. This review will summarize the published results that relate to innate immune responses against infections with human coronaviruses including SARS-CoV-1 and SARS-CoV-2 in both humans and animal models. The topics encompass the innate immune sensing of the virus to the dysregulation of various innate immune cells during infection and disease progression.

• 한국식품영양학회지
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• 제21권3호
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• pp.275-282
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• 2008

Hot-water($100^{\circ}C$) and cold-water($4^{\circ}C$) extracts of Taraxacum officinale root were assessed for the effects of innate and adaptive immune responses in mice. Hot water extracts(TO-100) and cold water extracts(TO-4) did not affect the viability of macrophages at concentrations below to 18 mg/ml and 8 mg/ml, respectively. The thioglycollate-induced macrophages cultured with TO-100 and TO-4 produced a significantly higher quantity of various cytokines, such as IL-6 and IL-12, than those treated with medium. This shows that the extracts potently stimulated the innate immune response. When mice were subcutaneously immunized(sc) with OVA+FIA(Freund's incomplete adjuvant)-emulsified TO-100, TO-100 did not affect the production of IgE, but enhanced the production of IgG1, IgG2a and IgG2b. The culture supernatant obtained from the splenocytes of mice treated with OVA+FIA-emulsified TO-100 also evidenced elevated levels of both OVA-specific Th1-type(IFN-$\gamma$) and Th2-type cytokines(IL-4, IL-6 and IL-10). These results suggested that TO-100 can modulate the immune responses to allergens in mice.

• Molecules and Cells
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• 제20권2호
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• pp.173-182
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• 2005

Heat shock protein gp96 is an endoplasmic reticulum chaperone, belonging to the HSP90 family. The function of gp96 as a molecular chaperone was discovered more than 10 years ago, but its importance has been overshadowed by the brilliance of its role in immune responses. It is now clear that gp96 is instrumental in the initiation of both the innate and adaptive immunity. Recently, the roles of gp96 in protein homeostasis, as well as in cell differentiation and development, are beginning to draw more attention due to rapid development in the structural study of HSP90 and some surprising new discoveries from genetic studies of gp96. In this review, we focus on the aspect of gp96 as an ER molecular chaperone in protein maturation, peptide binding and the regulation of its activity.