Immune Divergences between Skin and Respiratory Chemical Sensitizers Revealed by Mouse Single-Cell Transcriptomics

Methods

Female BALB/c mice were dermally exposed to a skin- (dinitrochlorobenzene, DNCB), or to a respiratory sensitizer (phthalic anhydride, PA) at day 0 (D0) and D5 to initiate allergic sensitization and at D10, D11 and D12 to induce elicitation. Auricular lymph nodes (LN) were collected at D0, D3, D7, D10 and D13. Single cell transcriptomic analyses were performed in order to identify immune cells proportions and markers expression.

Results: Exposure to both sensitizers induced a strong immune reaction demonstrated by an increase of mature B cells and an evolution of the T cell subpopulations, with an increase of follicular and memory T cells. The proportion of NKT, Th2 and Th9 cells and the levels of IgE increased specifically during PA exposure. Follicular, memory and helper T cells showed distinct transcriptomic responses to DNCB or PA.

The proportion of dendritic cells strongly increased starting from D10 in mice exposed to DNCB and those cells showed a specific genetic signature towards the skin sensitizer. Conclusion: A distinct transcriptomic signature was identified in immune cells during sensitization to DNCB or PA in this study.