Molecular cloning of a cystatin from parasitic intestinal nematode，Nippostrongylus brasiliensis.

寄生虫感染時の免疫応答には大きく分けて2つの型がある。蠕虫感染ではTh2型の免疫応答が優位となり、血清総IgE量の上昇、好酸球血症、肥満細胞増多などが特徴的に観察される。いっぽう、原虫感染においては、Th1型の免疫応答が主導となり細胞性殺寄生虫反応などによって寄生虫の排除にはたらく。申請者らは、リーシュマニア症の感染モデルにおいて、感染感受性マウスに対しリソソーム内カテプシンB選択的阻害剤であるCA074を投与することで免疫応答がTh2型からTh1型へと変化し感染抵抗性になることを発見した。申請者らはさらに、卵白アルブミン免疫マウスにおいても同様にCA074の投与で抗体産生などの免疫応答がTh2型からTh1型へと変化することを確認し、この現象がより普遍性を持つものであることを証明した。これらのことから、ある種の寄生虫感染に特徴的な免疫応答が抗原プロセッシングに関わる宿主リソソーム内酵素の種類によって選択的に誘導される可能性が考えられた。 いっぽう申請者らは、リーシュマニア感染マウスに対しリソソーム内カテプシンD阻害剤であるペプスタチンA を投与した場合にTh1型・Th2型双方の免疫応答が低下することを発見した。この現象も卵白アルブミン免疫マウスにおいて同様に観察された。これがTリンパ球に対する直接的・非特異的機能抑制ではないことを確認し、さらに詳細な解析により、宿主細胞内で抗原提示分子の輸送・調節にはたらくインバリアント鎖の分解抑制によるものであることを解明した。 更に申請者らは、マウス・ラットの腸管内寄生性線虫であるNippostrongylusbrasiliensisが、カテプシンB等を阻害するシステインプロテアーゼインヒビターを分泌することを発見し、この分子を新規にクローニングしニッポシスタチンと名付けた。ニッポシスタチンは試験管内でリソソームによる卵白アルブミンのプロセッシングを阻害した。ニッポシスタチンは卵白アルブミン免疫マウスへの生体内投与で脾細胞の抗原特異的増殖反応及びサイトカイン分泌を抑制し、抗原特異的IgE産生も低下させた。申請者らはN.brasiliensisが宿主内でこの分子を分泌することで 抗原プロセッシングを変化させ、宿主免疫を調節している可能性を示唆した。 以上申請者らは、寄生虫感染における宿主の免疫応答がリソソーム酵素の種類と機能によって異なるだけでなく、宿主リソソーム酵素が寄生虫による免疫回避・修飾機構の標的となりうることを明らかにした

Interaction of Psoriasis and Bullous Diseases

Patients with psoriasis are frequently complicated with autoimmune bullous diseases, especially, pemphigoid diseases. It has been known that one-third cases of anti-laminin gamma1 pemphigoid, formerly anti-p200 pemphigoid, are associated with psoriasis whereas bullous pemphigoid is the most frequently associated bullous disease in psoriasis cases regardless of the lack of detectable levels of the accompanying anti-laminin gamma1 autoantibodies. Despite several suggestions, however, the definitive reason of the striking association of psoriasis and these autoimmune bullous diseases remains elusive. In this review, we look over the epidemiological evidence of the association of psoriasis and autoimmune bullous diseases and the information of genetic susceptibilities of each disease, and discuss the possible mechanisms of their complication with reference to the recent understandings of each pathogenesis

Effects of Olopatadine Hydrochloride, a Histamine H1 Receptor Antagonist, on Histamine-Induced Skin Responses

Effects of olopatadine hydrochloride, a histamine H1 receptor antagonist, on histamine-induced skin responses were evaluated in 10 healthy subjects in comparison with placebo, fexofenadine hydrochloride, and bepotastine besilate. Olopatadine significantly suppressed histamine-induced wheal, flare, and itch, starting 30 minutes after oral administration. Olopatadine was more effective than fexofenadine and bepotastine. None of the drugs studied impaired performance of word processing tasks. These results suggest that olopatadine can suppress skin symptoms caused by histamine soon after administration

Molecular cloning of a cystatin from parasitic intestinal nematode, Nippostrongylus brasiliensis

A novel member of the cystatin family, nippocystatin (NbCys), was identified from excretory-secretory (ES)-products of a nematode Nippostrongylus brasiliensis, and the cDNA was cloned and sequenced. The mRNA of NbCys was confirmed to be expressed in both larvae and adults of the parasite. NbCys was translated as a proform with a single domain for secretion and was detected as a 14-kDa mature form in ES-products of the adult worm. Recombinant protein of NbCys profoundly inhibited the activity of cysteine proteases such as cathepsin L and B, but not that of cathepsin D, an aspartic protease. Furthermore, the ES-products had also been confirmed to inhibit cysteine proteases. Taken together, NbCys may play a role in evasion of N. brasiliensis from host defense systems, since cysteine proteases are known to participate in immune systems of infected hosts

Immune Control by TRAF6-Mediated Pathways of Epithelial Cells in the EIME (Epithelial Immune Microenvironment)

In the protective responses of epithelial tissues, not only immune cells but also non-immune cells directly respond to external agents. Epithelial cells can be involved in the organization of immune responses through two phases. First, the exogenous harmful agents trigger the primary responses of the epithelial cells leading to various types of immune cell activation. Second, cytokines produced by the immune cells that are activated directly by the external agents and indirectly by the epithelial cell products elicit the secondary responses giving rise to further propagation of immune responses. TRAF6 is a ubiquitin E3 ligase, which intermediates between various types of receptors for exogenous agents or endogenous mediators and activation of subsequent transcriptional responses via NF-kappaB and MAPK pathways. TRAF6 ubiquitously participates in many protective responses in immune and non-immune cells. Particularly, epithelial TRAF6 has an essential role in the primary and secondary responses via driving type 17 response in psoriatic inflammation of the skin. Consistently, many psoriasis susceptibility genes encode the TRAF6 signaling players, such as ACT1 (TRAF3IP2), A20 (TNFAIP3), ABIN1 (TNIP1), IL-36Ra (IL36RN), IkappaBzeta (NFKBIZ), and CARD14. Herein, we describe the principal functions of TRAF6, especially in terms of positive and regulatory immune controls by interaction between immune cells and epithelial cells. In addition, we discuss how TRAF6 in the epithelial cells can organize the differentiation of immune responses and drive inflammatory loops in the epithelial immune microenvironment, which is termed EIME

A Phenotypic Analysis of Involucrin-Membrane-Bound Ovalbumin Mice after Adoptive Transfer of Ovalbumin-Specific CD8⁺ T Cells

To investigate the mechanism of autoimmunity and peripheral tolerance in the skin, several transgenic mouse strains expressing membrane-bound ovalbumin (mOVA) as an epidermal self-antigen under the control of keratinocyte-specific promotors, such as keratin 5 and keratin 14, were employed in combination with adoptive transfer of CD8⁺ T cells from OT-I mice (OT-I T cells) that recognize an ovalbumin-derived peptide. However, these strains showed bodyweight loss and required additional inflammatory stimuli, such as γ-irradiation and tape-stripping, to induce skin inflammation. In this study, we generated a mouse strain expressing mOVA under the control of human involucrin promoter (involucrin-mOVA mice). In contrast to previous strains, involucrin-mOVA mice spontaneously developed skin inflammation after the transfer of OT-I T cells in the absence of external stimuli without significant bodyweight loss. We focused on the skin infiltration process of OT-I T cells and found that transferred OT-I T cells accumulated around the hair follicles in the early phase of skin inflammation, and in the later phase, the skin inflammation spontaneously resolved despite the remaining OT-I T cells in the skin. Our involucrin-mOVA mice will provide a promising tool to investigate the pathogenesis and the tolerance mechanisms of cytotoxic skin autoimmunity

A Case of Pulmonary Paragonimiasis with Involvement of the Abdominal Muscle in a 9-Year-Old Girl

In Korea, many people enjoy eating raw or underkooked freshwater crayfish and crabs which unfortunately may cause paragonimiasis. Here, we describe a case of pulmonary and abdominal paragonimiasis in a 9-year-old girl, who presented with a 1-month history of abdominal pain, especially in the right flank and the right inguinal area, with anorexia. A chest radiograph revealed pleural effusion in both lungs, and her abdominal sonography indicated an inflammatory lesion in the right psoas muscle. Peripheral blood analysis of the patient showed hypereosinophilia (66.0%) and an elevated total serum IgE level (>2,500 IU/ml). The pleural effusion tested by ELISA were also positive for antibodies against paragonimiasis. Her dietary history stated that she had ingested raw freshwater crab, 4 months previously. The diagnosis was pulmonary paragonimiasis accompanied by abdominal muscle involvement. She was improved after 5 cycles of praziquantel treatment and 2 times of pleural effusion drainage. In conclusion, herein, we report a case of pulmonary and abdominal paragonimiasis in a girl who presented with abdominal pain and tenderness in the inguinal area

Regulation of the host immune system by helminth parasites

Helminth parasite infections are associated with a battery of immunomodulatory mechanisms, which impact all facets of the host immune response to ensure their persistence within the host. This broad-spectrum modulation of host immunity has intended and unintended consequences, both advantageous and disadvantageous. Thus the host may benefit from suppression of collateral damage during parasite infection, and from reduced allergic, autoimmune and inflammatory reactions. However, helminth infection can also be detrimental in reducing vaccine responses, increasing susceptibility to co-infection, and potentially reducing tumor immunosurveillance. In this review we will summarize the panoply of immunomodulatory mechanisms used by helminths, their potential utility in human disease, and prospective areas of future research