Céline Vandamme1, Marja Rytkönen-Nissinen1, Tapio Lönnberg2, Jukka Randell3, Rauno J Harvima4, Tuure Kinnunen5, Tuomas Virtanen1. 1. Department of Clinical Microbiology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland. 2. Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland; InFLAMES Research Flagship Center, University of Turku, Turku, Finland. 3. Department of Pulmonary Diseases, Kuopio University Hospital, Kuopio, Finland. 4. Department of Dermatology, Kuopio University Hospital and University of Eastern Finland, Kuopio, Finland. 5. Department of Clinical Microbiology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Eastern Finland Laboratory Centre (ISLAB), Kuopio, Finland. Electronic address: tuure.kinnunen@uef.fi.
Abstract
BACKGROUND: Allergen-specific type 2 CD4+ TH2 cells are critically involved in the pathogenesis of IgE-mediated allergic diseases. However, the heterogeneity of the TH2 response has only recently been appreciated. OBJECTIVE: We sought to characterize at the single-cell level the ex vivo phenotype, transcriptomic profile, and T-cell receptor (TCR) repertoire of circulating CD4+ T cells specific to the major dog allergens Can f 1, Can f 4, and Can f 5 in subjects with and without dog allergy. METHODS: Dog allergen-specific memory CD4+ T cells were detected ex vivo by flow cytometry using a CD154-based enrichment assay and single-cell sorted for targeted gene expression analysis and TCR sequencing. RESULTS: Dog allergen-specific T-cell responses in allergic subjects were dominantly of TH2 type. TH2 cells could be phenotypically further divided into 3 subsets, which consisted of TH2-like (CCR6-CXCR3-CRTH2-), TH2 (CCR6-CXCR3-CRTH2+CD161-), and TH2A (CCR6-CXCR3-CRTH2+CD161+CD27-) cells. All these subsets were nonexistent within the allergen-specific T-cell repertoire of healthy subjects. Single-cell transcriptomic profiling confirmed the TH2-biased signature in allergen-specific T cells from allergic subjects and revealed a TH1/TH17 signature in nonallergic subjects. TCR repertoire analyses showed that dog allergen-specific T cells were diverse and allergic subjects demonstrated less clonality compared to nonallergic donors. Finally, TCR and transcriptomic analyses revealed a close relationship between TH2-like, TH2, and TH2A cells, with the last ones representing the most terminally differentiated and highly polarized subtype. CONCLUSIONS: Our study demonstrates heterogeneity within allergen-specific TH2 cells at the single-cell level. The results may be utilized for improving immune monitoring after allergen immunotherapy and for designing targeted immunomodulatory approaches.
BACKGROUND: Allergen-specific type 2 CD4+ TH2 cells are critically involved in the pathogenesis of IgE-mediated allergic diseases. However, the heterogeneity of the TH2 response has only recently been appreciated. OBJECTIVE: We sought to characterize at the single-cell level the ex vivo phenotype, transcriptomic profile, and T-cell receptor (TCR) repertoire of circulating CD4+ T cells specific to the major dog allergens Can f 1, Can f 4, and Can f 5 in subjects with and without dog allergy. METHODS: Dog allergen-specific memory CD4+ T cells were detected ex vivo by flow cytometry using a CD154-based enrichment assay and single-cell sorted for targeted gene expression analysis and TCR sequencing. RESULTS: Dog allergen-specific T-cell responses in allergic subjects were dominantly of TH2 type. TH2 cells could be phenotypically further divided into 3 subsets, which consisted of TH2-like (CCR6-CXCR3-CRTH2-), TH2 (CCR6-CXCR3-CRTH2+CD161-), and TH2A (CCR6-CXCR3-CRTH2+CD161+CD27-) cells. All these subsets were nonexistent within the allergen-specific T-cell repertoire of healthy subjects. Single-cell transcriptomic profiling confirmed the TH2-biased signature in allergen-specific T cells from allergic subjects and revealed a TH1/TH17 signature in nonallergic subjects. TCR repertoire analyses showed that dog allergen-specific T cells were diverse and allergic subjects demonstrated less clonality compared to nonallergic donors. Finally, TCR and transcriptomic analyses revealed a close relationship between TH2-like, TH2, and TH2A cells, with the last ones representing the most terminally differentiated and highly polarized subtype. CONCLUSIONS: Our study demonstrates heterogeneity within allergen-specific TH2 cells at the single-cell level. The results may be utilized for improving immune monitoring after allergen immunotherapy and for designing targeted immunomodulatory approaches.