(1-->3)-beta-D-glucanemia in deep mycosis

Janus-Faced Molecules against Plant Pathogenic Fungi

The high cytotoxicity of the secondary metabolites of mycotoxins is capable of killing microbes and tumour cells alike, similarly to the genotoxic effect characteristic of Janus-faced molecules. The "double-edged sword" effect of several cytotoxins is known, and these agents have, therefore, been utilized only reluctantly against fungal infections. In this review, consideration was given to (a) toxins that could be used against plant and human pathogens, (b) animal models that measure the effect of antifungal agents, (c) known antifungal agents that have been described and efficiently prevent the growth of fungal cells, and (d) the chemical interactions that are characteristic of antifungal agents. The utilization of apoptotic effects against tumour growth by agents that, at the same time, induce mutations may raise ethical issues. Nevertheless, it deserves consideration despite the mutagenic impact of Janus-faced molecules for those patients who suffer from plant pathogenic fungal infections and are older than their fertility age, in the same way that the short-term cytotoxicity of cancer treatment is favoured over the long-term mutagenic effect.

[Validation of a New (1 → 3)-β-D-Glucan Test Kit, Fungitec G Test MKⅡ " Nissui "]

Using 415 residual blood samples subjected to (1→3) -β-D-glucan assay, we studied the correlation of measurement results between Fungitec G Test MKII "Nissui" (Nissui Pharmaceutical Co., Ltd., Tokyo) and its predecessor, Fungitec G Test MK (Seikagaku Corporation, Tokyo), which is now out of production. Their major difference is that MK II uses reagents derived from blood cells of Limulus polyphemus, the American horseshoe crab, whereas MK used those of Tachypleus tridentatus, an Asian horseshoe crab. Passing-Bablok analysis showed a linear regression with nearly one-to-one correspondence (slope=1.065, intercept=-0.287) between the two test kits over the regular range of measurements (4.0 pg/ml -500 pg/ml ). This was also true when data were subdivided and analyzed in the low to medium (≦150 pg/ml ) and in the low range (≦50 pg/ml ). There were several cases, however, that showed a wide discrepancy between the pair of measurements. This discrepancy is believed to be due in part to the difference between Limulus and Tachypleus in their reactivity to β-glucans with diverse side chains. Despite of this, the even distribution on either side of the regression line of those samples that are associated with deep fungal infection and the abrupt disappearance of such samples below 20 pg/ml attest that MK II "Nissui" is an acceptable successor of MK.

The influence of glucan polymer structure and solution conformation on binding to (1-->3)-beta-D-glucan receptors in a human monocyte-like cell line

Glucans are (1-3)-beta-D-linked polymers of glucose that are produced as fungal cell wall constituents and are also released into the extracellular milieu. Glucans modulate immune function via macrophage participation. The first step in macrophage activation by (1-3)-beta-D-glucans is thought to be the binding of the polymer to specific macrophage receptors. We examined the binding/uptake of a variety of water soluble (1-3)-beta-D-glucans and control polymers with different physicochemical properties to investigate the relationship between polymer structure and receptor binding in the CR3- human promonocytic cell line, U937. We observed that the U937 receptors were specific for (1-->3)-beta-D-glucan binding, since mannan, dextran, or barley glucan did not bind. Scleroglucan exhibited the highest binding affinity with an IC(50)of 23 nM, three orders of magnitude greater than the other (1-->3)-beta-D-glucan polymers examined. The rank order competitive binding affinities for the glucan polymers were scleroglucan>>>schizophyllan > laminarin > glucan phosphate > glucan sulfate. Scleroglucan also exhibited a triple helical solution structure (nu = 1.82, beta = 0.8). There were two different binding/uptake sites on U937 cells. Glucan phosphate and schizophyllan interacted nonselectively with the two sites. Scleroglucan and glucan sulfate interacted preferentially with one site, while laminarin interacted preferentially with the other site. These data indicate that U937 cells have at least two non-CR3 receptor(s) which specifically interact with (1-->3)-beta-D-glucans and that the triple helical solution conformation, molecular weight and charge of the glucan polymer may be important determinants in receptor ligand interaction.