Impact of ovalbumin-induced sensitization/anaphylactic shock and gut microbiome dynamics in Wistar rats

The temporal relationship between the immune cell activation of allergic inflammation and the corresponding shift in host-associated microbiome remains elusive. We investigated the dynamics of mycobiome-bacteriome profile, mast cells and eosinophils during ovalbumin (OVA)-induced sensitization and anaphylactic shock in Wistar rats. The earliest response among studied tissues was appearance of mast cells and eosinophils in lung. The mycobiome during sensitization was dominated by Kazachstania, Trichosporon, and Candida, with a shift to Aspergillus, Penicillium and Wallemia during AS. The sensitization bacteriome was dominated by Prevotella and Ruminococcus, while norank_o_Clostridia_UCG014 dominated in AS. The high fungal diversity of AS contrasted with the comparative stability of bacteriome alpha diversity, but beta diversity showed remarkable compositional remodeling. The intra- and inter-kingdom correlation of control fungal and bacterial communities was transformed during allergic sensitization and AS, into active intra- and inter-kingdom competition and remodeling. Correlation analysis revealed enteric microbiome associations with inflammatory or tolerance-linked biomarkers of sensitization and AS. Metagenomic functional analysis indicated microbial dysbiosis. Our results suggest that OVA sensitization associated with allergic innate immune effector cells of the lungs. Allergic sensitization and AS were accompanied by multi-kingdom enteric ecosystem remodeling, defined by network collapse and appearance of specific microbial associations. These findings encourage further mechanistic investigation of multi-kingdom dysbiosis in severe allergic conditions