Single-cell transcriptional analysis reveals allergen-specific signatures in human γδ T cells

The role of gamma-delta T (γδ T) cells in immune responses to common allergens is poorly understood. Here, we utilized single-cell (sc) transcriptomic analysis of allergen-reactive γδ T cells in humans to characterize the transcriptional landscapes and TCR repertoires in response to cockroach (CR) and mouse (MO) allergens. Using a potentially novel activation-induced marker (AIM) assay that allows detection of γδ T cells combined with scRNA sequencing and TCR repertoire analysis, we identified both shared and allergen-specific γδ T cell activation patterns and gene expression profiles. While CR extract activated both Vδ1 and Vδ2 subsets, MO extract primarily stimulated Vδ2 cells. Our analysis revealed allergen-specific clusters with distinct functional signatures, including enhanced inflammatory responses and cytotoxic effector functions in MO-specific γδ T cells and natural killer cell-mediated immunity and IFN-γ signaling in CR-specific populations. Comparison of allergic and nonallergic individuals highlighted differences in gene expression and TCR repertoires, including a higher IFNG expression in the CR-allergic compared with nonallergic cohorts, suggesting that phenotypic and functional differences are associated with γδ T allergen responses. This study provides insights into the cellular and molecular heterogeneity and functionality of allergen-reactive γδ T cells, offering a foundation for understanding their role in allergic diseases and potential therapeutic interventions.