Growth, allergen profile and microbiome studies in Dermatophagoides pteronyssinus cultures

Abstract

Mites are mass-cultured to manufacture allergen extracts for allergy diagnostics and therapeutic treatment. The present study focused on characterizing the growth, the allergen profile, and the microbiome of Dermatophagoides pteronyssinus. Samples from three cultures were taken at 10 different times of development. Mite population, protein profile, total protein content and major allergen levels (Der p 1, Der p 2, Der p 23) were monitored. Additionally, the progression of the allergenicity was studied by immunoblot using a pool of sera from allergic patients. Regarding the microbiome study, genomic DNA from 600 adult mites from the last day of the culture was isolated. Mite microbiome was characterized by sequencing the 16rRNA gene. Taxonomic analyses were performed using Qiime2 software. Endotoxin content was also analyzed. The culture had a fast and unrelenting evolution. Mite density, total protein content, Der p 1 and Der p 23 levels were increased progressively during the culture. Furthermore, the growth profile had a good correlation with the total protein content (r Pearson = 0.84; p = 0.01) and the levels of Der p 1, Der p 2 and Derp 23 (r = 0.69; p = 0.0042; r = 0.86; p < 0.0001; r = 0.7; p = 0.0036). According to the microbiome studies, the results confirm the presence of non-pathogenic bacteria, being firmicutes and actinobacteria the most common bacterial taxa, with a very low content of Gram-negative bacteria and endotoxin content. The results of the growth, allergen profile and microbiome in our mite cultures confirm our in-depth knowledge, expertise, and control of culture processes to produce high-quality allergen extracts.