Performance of Two Different Limulus Amebocyte Lysate Assays for the Quantitation of Fungal Glucan

Abstract

This study examined the response of various forms and sources of glucans toward two different Limulus amebocyte lysate (LAL) methods, the modified LAL, and Glucatell. The glucans studied were curdlan, laminarin, yeast glucan, barley glucan, paramylon, pullulan, pustulan, mannan, and pachyman (as part of the Glucatell kit). Both methods provided largely similar results for each of the glucans; however, the Glucatell method yielded slightly higher responses to certain structures that may not necessarily be of fungal origin, leading to falsely greater positive results. The performance of each method to measure fungal glucan concentration specifically was then assessed.

Exposure to Beta-(1,3)-D-Glucan in House Dust at Age 7–10 Is Associated with Airway Hyperresponsiveness and Atopic Asthma by Age 11–14

“…Though within-home variance of beta-glucan measurements has been found to be small [64] this may not be applicable to all climates and populations. Our method for beta glucan detection [36] may also detect plant glucans and only one dust sample was collected over the 4 year assessment, which may not detect mould beta-glucan exposure changes. While Heinrich et al [65] concluded that beta-glucan levels in a single-point dust sample were representative of exposure for at least a one year period, this may not be true for all populations.…”

“…Factor C, originally used for endotoxin detection, was replaced by Factor G, allowing for (1R3)-b-D-glucan detection and avoiding false positive results from cross detection. The Glucatell assay predominantly measures fungal glucans but can also detect glucans from plants sources [36] A 5 mg extraction of each dust sample was diluted with 1 mL 0.3N Sodium Hydroxide (NaOH) and shaken at room temperature for one hour. The LAL and chromogenic substrate solutions were then added.…”

Mold allergy revisited

“…18 The cell walls of grasses and fungi contain b-1,3-D-glucan, sometimes in mixtures with other glucans. Studies in humans suggest that there is a doseresponse relationship between exposure to airborne fungal glucan and respiratory symptoms, itching skin, hoarseness, and fatigue.…”

Evidence for the detection of non-endotoxin pyrogens by the whole blood monocyte activation test

“…evaluation of the pyrogenic capacity of the surface lipophilic compounds of fungi in LAL or the rabbit test is also difficult, as these surface compounds are modified with glycans, e.g., with GPI-anchors (Costachel et al, 2005). Moreover, there are hints from glucan research pointing to impurities and lipophilic contamination of these preparations, which may play a causative role in the inability of even modified LAL tests -Glucatell -to adequately mirror the pyrogenic capacity of fungal stimuli by producing "falsely greater positive results" (Ikeda et al, 2005;Cherid et al, 2011).…”