Exposure to Vishniacozyma victoriae elicits airway inflammation and a CD4+ T cell-driven lymphocytic response.

Abstract Like the pathogenic yeast Cryptococcus neoformans, Vishniacozyma victoriae (syn. Cryptococcus victoriae), a non-pathogenic yeast, has been associated with allergic airway disease. Although V. victoriae is frequently detected in indoor environments, the impact of repeated exposure is currently unknown. In this study, mice were exposed via oropharyngeal aspiration to V. victoriae or C. neoformans every other day for a total of six exposures, and responses were analyzed 1 day and 21 days post final exposure. As expected, repeated exposure to C. neoformans resulted in an increase of myeloid and lymphoid cells in the bronchoalveolar lavage fluid (BALF), granuloma formation with intralesional yeast, and peribronchiolar and perivascular inflammation 1 day post exposure. This response was exacerbated 21 days post exposure as the yeast cells replicated. Repeated exposure to V. victoriae resulted in an increase in eosinophils, Ly6Chi/int monocytes, and CD103+ dendritic cells in the BALF, and mild perivascular and peribronchiolar inflammation 1 day post exposure. Surprisingly, V. victoriae cells were present in the lungs of exposed mice 21 days post exposure, and the response shifted toward a nodular lymphocytic response with an increase of CD4+ T cells in the BALF. Lastly, C. neoformans exposure was predicted to activate antigen presentation, B cell development and Th2 proteomic pathways, whereas V. victoriae was predicted to activate VDR/RXR activation, Granzyme A signaling, and IGF-1 signaling pathways 21 days post exposure. The results of this study suggest that exposure to environmentally ubiquitous V. victoriae may exacerbate allergic airway disease, although not to the extent of exposure to pathogenic C. neoformans. Interagency Agreement between NIEHS & NIOSH: AES 12007001-1-0-6