Scientific Publications by FDA Staff

J Endotoxin Res 2006;12(4):241-5

beta-Glucans in standardized allergen extracts.

Finkelman MA, Lempitski SJ, Slater JE

Slater JE, US FDA, CBER, HFM 422,1401 Rockville Pike, Rockville, MD 20852 USA US FDA, CBER, Rockville, MD 20852 USA Associates Cape Cod Inc, E Falmouth, MA USA

BACKGROUND: Allergen extracts contain variable quantities of bacterial endotoxin. Recent studies have suggested that (1-->3)-beta-D-glucans (beta-glucans), also microbial cell wall components, may have adjuvant properties that could affect allergen immunotherapy. OBJECTIVE: To determine the quantities of beta-glucans in standardized allergen extracts. MATERIALS AND METHODS: Ninety-four lots of 13 standardized allergen extracts were tested for beta-glucan content by Glucatell assay, and for endotoxin content by a specific, chromogenic formulation of the Limulus amebocyte lysate test. RESULTS: Standardized allergen extracts contain variable quantities of endotoxins and beta-glucans. As in our previous work, endotoxin activity was greatest in cat pelt and Dermatophagoides farinae, and least in the pollens. There was no correlation between endotoxin and beta-glucan levels (r = 0.1887; P = 0.07). beta-Glucan content was highest for grass pollen (median content, 10.6 ng/ml; range, 0.4-41.8 ng/ml), ragweed pollen (32.9 ng/ml; range, 6.5-41.2 ng/ml), and cat pelt (25.5 ng/ml; range, 16.7-41.1 ng/ml), and lowest for cat hair (4.9 ng/ml; range, 1.2-10.3 ng/ml), D. farinae (1.2 ng/ml; range, 0.4-5.2 ng/ml) and Dermatophagoides pteronyssinus (1.8 ng/ml; range, 0.4-6.7 ng/ml). CONCLUSIONS: beta-Glucans are present in standardized allergen extracts. The effects of these quantities of beta-glucans on allergen immunotherapy and allergen skin testing require further study.