A7: CD4+ T cell receptor sequences during progression towards experimental pemphigoid

Background. In mouse models of pemphigoid, presence of autoantibodies at the dermal-epidermal junction is not sufficient to induce pathology (J Immunol 187:5043, J Invest Dermatol 140:1713). Moreover, our data demonstrated that PD pathogenesis correlates with IFN gamma-producing Th1 cells, whereas IL-4-producing Th2 or IL-10-producing Tregs suppress disease manifestation. Because lineage decision of CD4+ T cell differentiation is controlled by the T cell receptor (TCR) signaling strength, we hypothesize that T cell subsets emerge from distinct T cell clones, which compete with each other for survival and number of progenies. Eventually, during the transition from symptomless autoimmunity to autoimmune disease, Th1 cells become superior and accumulate over time. Our preliminary data revealed that the clinical manifestation of PD correlates with shifts in the V-J gene usage of the TCR-Beta chains (J Invest Dermatol. in press, PMID: 32057838, Fig. A7-1).

Objective. (i) Characterize the disease-specific TCR sequences and transcriptomes of CD4 subsets, (ii) explore disease-specific changes in the Th1, Th2 and Treg compartments in PD mouse models, and (iii) identify factors that modulate the ratio of disease-associated T cell clones.

Work program. Together with A9, compare the TCR-Beta sequences and transcriptomes of draining lymph nodes and skin lesions from healthy with those from pre-diseased and diseased mice. FACS will be used to define T cell subsets using surface markers, transcription factors and cytokines. Single-cell expression profiling with the BD Rhapsody Single Cell Analysis System will complement traditional FACS analysis. To confirm the crucial role of T cells, in vitro-expanded individual T cell clones will be transferred. To study the role of antigen presentation on T cell clonality and on disease manifestation, B cells deficient for MHC II and co-stimulation-blocking anti-CD40L antibodies will be used.