総説・解説等

In order to establish immunological detection methods for severe acute respiratory syndrome coronavirus (SARS-CoV), we established monoclonal antibodies directed against structural components of the virus. B cell hybridomas were generated from mice that were hyper-immunized with inactivated SARS-CoV virion. By screening 2,880 generated hybridomas, we established three hybridoma clones that secreted antibodies specific for nucleocapsid protein (N) and 27 clones that secreted antibodies specific for spike protein (S). Among these, four S-protein specific antibodies had in vitro neutralization activity against SARS-CoV infection. These monoclonal antibodies enabled the immunological detection of SARS-CoV by immunofluorescence staining, Western blot or immunohistology. Furthermore, a combination of monoclonal antibodies with different specificities allowed the establishment of a highly sensitive antigen-capture sandwich ELISA system. These monoclonal antibodies would be a useful tool for rapid and specific diagnosis of SARS and also for possible antibody-based treatment of the disease.

青そう子抽出エキス(CAE)はColon26-L5の肝転移を抑制すること,免疫系細胞の中でもmacrophageに作用し,IL-12産生を誘導することを明らかにした.今回の実験的肝転移モデルにおいて,CAEを腫瘍移植前に投与することにより,macrophageからのIL-12産生を誘導し,その結果としてColon26-L5の実験的肝転移が抑制されることが示唆された

十全大補湯の経口投与により,Colon26-L5結腸癌の実験的肝転移が著明に抑制されることが明らかとなり,その転移抑制の機序として,macrophageとT細胞が関係していることが示された.十全大補湯は,原発巣の外科切除前或いは後に経口投与することにより,微小肝転移の防止に有用であると考えられる

十全大補湯は癌のプログレッションを抑制することが明らかとなり,特に癌の悪性化変換の初期の段階に作用する可能性が示唆された

癌転移阻止効果の増強を目的に,アルギニン-グリシン-アスパラギン酸(RGD)ペプチドが擬似ペプチド化された配列を2つ有する新規擬似ペプチド(FC-336)を作成した.FC-336投与はアルギニン-グリシン-アスパラギン酸-セリン(RGDS)に比べてB16-BL6黒色腫の実験的肺転移を用量依存的に抑制した.Colon 26結腸癌高転移株(L5)による実験的肝転移モデルでも,FC-336の門脈内同時投与或いは腫瘍移植後の5回の静脈内投与により,転移抑制と生存期間の延長がみられた.FC-336はin vitroにおける癌細胞の基底膜浸潤・接着・移動に対してRGDSに比べて強くはないが,濃度依存的な抑制効果を示したゼラチンザイモグラムにおいて,FC-336はMMP-2,-9によるゼラチン基質の分解を抑制した

口腔バイオフィルム感染症の予防には、細菌の付着を抑制することが効果的な方策であると考えられる。近年、細菌を付着させにくくする"撥菌"という概念が提唱された。この"撥菌材"について、材料表面をコーティングすることにより、その性状を超親水性に改変する2-methacryloyloxyethyl phosphorylcholine(MPC)-polymerが開発された。筆者らが行ってきたMPC-polymerのオーラルケアへの応用に関する研究を紹介した。

The mucosal adjuvant effect of synthetic double-stranded RNA polyriboinosinic polyribocytidylic acid [poly(I:C)] against influenza virus was examined under intranasal coadministration with inactivated hemagglutinin (RA) vaccine in BALB/c mice and was shown to have a protective effect against both nasal-restricted infection and lethal lung infection. Intranasal administration of vaccine from PR8 (H1N1) with poly(I:C) induced a high anti-HA immunoglobulin A (IgA) response in the nasal wash and IgG antibody response in the serum, while vaccination without poly(I:C) induced little response. Intracerebral injection confirmed the safety of poly(I:C). In addition, we demonstrated that administration of poly(I:C) with either A/Beijing (H1N1) or A/Yamagata (H1N1) vaccine conferred complete protection against PR8 challenge in this mouse nasal infection model, suggesting that poly(I:C) possessed cross-protection ability against variant viruses. To investigate the mechanism of the protective effect of poly(I:C), mRNA levels of Toll-like receptors and cytokines were examined in the nasal-associated lymphoid tissue after vaccination or virus challenge. Intranasal administration of HA vaccine with poly(I:C) up-regulated expression of Toll-like receptor 3 and alpha/beta interferons as well as Th1- and Th2-related cytokines. We propose that poly(I:C) is a new effective intranasal adjuvant for influenza virus vaccine.

The recent emergence of severe acute respiratory syndrome (SARS) was caused by a novel coronavirus, SARS-CoV. It spread rapidly to many countries and developing a SARS vaccine is now urgently required. In order to study the immunogenicity of UV-inactivated purified SARS-CoV virion as a vaccine candidate, we subcutaneously immunized mice with UV-inactivated SARS-CoV with or without an adjuvant. We chose aluminum hydroxide gel (alum) as an adjuvant, because of its long safety history for human use. We observed that the UV-inactivated SARS-CoV virion elicited a high level of humoral immunity, resulting in the generation of long-term antibody secreting and memory B cells. With the addition of alum to the vaccine formula, serum IgG production was augmented and reached a level similar to that found in hyper-immunized mice, though it was still insufficient to elicit serum IgA antibodies. Notably, the SARS-CoV virion itself was able to induce long-term antibody production even without an adjuvant. Anti-SARS-CoV antibodies elicited in mice recognized both the spike and nucleocapsid proteins of the virus and were able to neutralize the virus. Furthermore, the UV-inactivated virion induced regional lymph node T-cell proliferation and significant levels of cytokine production (IL-2, IL-4, IL-5, IFN-gamma and TNF-alpha) upon restimulation with inactivated SARS-CoV virion in vitro. Thus, a whole killed virion could serve as a candidate antigen for a SARS vaccine to elicit both humoral and cellular immunity.