Ship-in-bottle synthesis of the mixed-layered compounds of clay silicate/zirconium phosphate.

An attempt was made to synthesize artificial mixed-layered compounds between montmorillonite silicate and α-zirconium phosphate using a ship-in-bottle approach. The interlayer cations of montmorillonite were first exchanged with hydroxy-zirconium oligomeric cations, which were then subjected to a reaction with phosphoric acid or phenylphosphoric acid to develop α-zirconium phosphate layers (Zr(R-OPO3)2; R = H, C6H5) between the clay silicate layers. The attempt of the reaction with phosphoric acid failed; hydroxy-zirconium cations were removed out of the interlayer space, forming α-zirconium phosphate outside of montmorillonite. The phenylphosphate derivative, montmorillonite/Zr(C6H5OPO3)2, with a regular mixed-layered structure has been successfully obtained, showing a basal spacing corresponding to the sum of the thicknesses of the individual layers. When a polyvinyl alcohol (PVA) aqueous solution was used in the preparation of the hydroxy-zirconium exchanged montmorillonite, PVA was incorporated with hydroxy-zirconium complex cations between the silicate layers. The resulting compound can adsorb phosphate ions. Although this is not a mixed-layered compound in the context of this study, the selective and reversible phosphate ion exchange properties are worth noting for future study.

Beta-mannosyl linkages negatively regulate anaphylaxis and vasculitis in mice, induced by CAWS, fungal PAMPS composed of mannoprotein-beta-glucan complex secreted by Candida albicans.

Candida albicans water soluble fraction (CAWS) is a water-soluble extracellular mannoprotein-beta-glucan complex obtained from the culture supernatant of Candida albicans, which grows in a chemically defined medium. CAWS induced toxic reactions, such as acute anaphylactoid reaction, by intravenous administration and coronary arteritis by intraperitoneal administration. To clarify the structure responsible for these toxic reactions, C. albicans was cultured in pH- and temperature-controlled conditions and prepared with CAWS with or without the beta-1,2-linked mannosyl segment (BM). The structure of CAWS was assessed by immunochemical and spectroscopic methodologies, and we found that CAWS prepared under the natural culture conditions contained only small amounts of BM and CAWS prepared at neutral conditions at 27 degrees C contained a significantly higher percentage of BM. Both the acute lethal toxicity and coronary arteritis induction was significantly more severe in the absence of BM. Activation of a complement pathway, the lectin pathway, by CAWS was significantly stronger in the absence of BM. These facts strongly suggest that BM linkages in CAWS negatively modulate acute and chronic toxicity of CAWS, and may be strongly related to the lectin pathway of the complement activation.

[Histopathological examination and analysis of mortality in DBA/2 mouse vasculitis induced with CAWS, a water-soluble extracellular polysaccharide fraction obtained from Candida albicans].

CAWS, a water-soluble extracellular polysaccharide fraction obtained from the culture supernatant of Candida albicans, is one of the fungal pathogen-associated molecular patterns (PAMPs). It has been reported to show potent activity inducing arteritis and coronaritis in mice. Especially, CAWS-induced arteritis has a 100% incidence and severe mortality in the DBA/2 mouse strain. This artificial vasculitis was reported to provide a good murine model of Kawasaki disease and other inflammatory vascular disease. However, severe mortality was observed only in DBA/2 mice, which is a CAWS-sensitive strain. In this study, to clarify the mechanisms of CAWS-induced arteritis and mortality, we investigated microscopic histopathological changes in cardiovascular tissues in DBA/2 mice. Severe inflammatory infiltration was observed from the external elastic lamina in the aorta and proximal coronary arteries within 1 week after CAWS administration. Severe stenosis of the aorta and coronary arteries was observed more than 3 weeks after CAWS administration. Fibrinoid necrosis was observed in these vessel walls. All CAWS-treated mice died between the fifth and twelfth week after administration. Severe inflammatory change with aortic valve transformation suggested that CAWS-treated mice died of valvular endocarditis or cardiac dysfunction. Based on the simple induction method and complete incidence, these data suggest that CAWS-induced arteritis is a good model of not only Kawasaki disease but also other cardiovascular diseases such as valvular endocarditis.

Lethal and severe coronary arteritis in DBA/2 mice induced by fungal pathogen, CAWS, Candida albicans water-soluble fraction.

CAWS is a microbial pathogen-associated molecular patterns (PAMPs) produced by Candida albicans. CAWS is a mannoprotein-beta-glucan complex and secreted into the culture supernatant. CAWS has various biological effects, causing acute shock and disrupting vascular permeability. Intraperitoneal administration of CAWS induces coronary arteritis in various strains of inbred mice. The CAWS-induced coronary arteritis is strain-dependent and most severe in DBA/2 mice with a significant number of these animals expiring with cardiomegaly during the observation period. In vivo and in vitro, splenocytes of DBA/2 mice produced various cytokines, such as IL-6, TNF-alpha, and IFN-gamma in response to CAWS. GM-CSF was also produced in response to CAWS. The production of cytokines was significantly enhanced in the presence of recombinant GM-CSF. In contrast, anti-GM-CSF significantly reduced the production of TNF-alpha and IFN-gamma. Augmented production of cytokines in response to CAWS would be a key to the severity of coronary arteritis.

Role of anti-beta-glucan antibody in host defense against fungi.

We have recently detected an anti-beta-glucan antibody in normal human and normal mouse sera. The anti-beta-glucan antibody showed reactivity to pathogenic fungal Aspergillus and Candida cell wall glucan. Anti-beta-glucan antibody could bind whole Candida cells. It also enhanced the candidacidal activity of macrophages in vitro. The anti-beta-glucan antibody titer of DBA/2 mice intravenously administered either Candida or Aspergillus solubilized cell wall beta-glucan decreased remarkably dependent on dose. Moreover, in deep mycosis patients, the anti-beta-glucan antibody titer decreased, and this change correlated with clinical symptoms and other parameters such as C-reactive protein. It was suggested that the anti-beta-glucan antibody formed an antigen-antibody complex and participated in the immune response as a molecule recognizing pathogenic fungi.