Diet influences growth rates and allergen and endotoxin contents of cultured Dermatophagoides farinae and Dermatophagoides pteronyssinus house dust mites

Abstract

Background: The house dust mites Dermatophagoides farinae and Dermatophagoides pteronyssinus are cultured to obtain material for the production of allergen extracts for research, diagnostic and immunotherapeutic purposes.

Methods: We cultured mites on two different diets that supported thriving populations and determined the population growth rates, dynamics of allergen accumulation, and endotoxin concentrations in extracts made from mites harvested from the cultures.

Results: D. farinae populations grew faster on a diet of rodent chow/yeast than on an egg/yeast diet but a larger peak population size was achieved on the egg/yeast diet. Diet influenced the dynamics of the production of groups 1 and 2 allergens and the group 1/2 ratios for both species. To population peak, Der f 1 was produced at a faster rate on the chow/yeast diet but greater amounts of Der f 1 were produced by mites grown on the egg/yeast diet. D. pteronyssinus populations grew faster and achieved greater density on the egg/yeast diet compared to the chow/yeast diet. D. pteronyssinus produced more Der p 1 than Der p 2 when grown on chow/yeast while more Der p 2 than Der p 1 was produced on egg/yeast. Endotoxin concentrations in extracts made from whole cultures for both species at maximum population density were very different in the two diets. Washing the mites resulted in the loss of up to 88% of the allergen.

Conclusion: Mite-culturing diet directly effects population growth, the dynamics of allergen accumulation, the group 1/2 allergen ratio and the endotoxin contents in extracts of cultured house dust mites.