CD1 and lipid dependence of the human CD4-/CD8- double-negative T cell repertoire

Summary: Abstract Body: Double-negative T cells (DN T cells), which lack both CD4 and CD8 co-receptor expression, represent a small fraction of T cells in peripheral blood but are more prevalent in tissues. These T cells are often expanded in autoimmune disease, in particular in SLE. In preclinical models, DN T cells have been harnessed for anti-tumor immunity, transplant tolerance, and the prevention of graft-versus-host disease (GvHD). The apparent contradiction between their pro-inflammatory and immunoregulatory roles is likely due to the heterogeneity within the DN T cell population. Indeed, our preliminary analysis of αβ double-negative (DN) T cells from 19 healthy donors using single-cell RNA sequencing and TCR sequencing revealed several clusters with distinct gene expression profiles, reflecting both pro-inflammatory and anti-inflammatory functions. Given the absence of CD4 and CD8 co-receptors, DN T cells likely interact with antigen-presenting molecules other than MHC. In line with this, we have recent data showing that the human DN αβ T cell repertoire is highly enriched for T cell populations restricted by CD1 proteins. These non-polymorphic antigen-presenting molecules present lipid antigens to T cells. Using fluorescently labeled CD1 tetramers, we identified distinct populations of DN T cells restricted by CD1a, CD1b, CD1c, and CD1d, all of which exhibited CD1-autoreactivity, meaning they bind to CD1 molecules presenting endogenous self-lipid antigens. Using Clonotype Neighbor Graph Analysis (CoNGA), we are determining correlations between gene expression profiles and TCR sequences, and are further linking TCR sequences to CD1-specificities to identify novel conserved CD1-autoreactive T cell populations. These studies will provide a detailed and comprehensive view of the human DN T cell repertoire, and provide a resource for further investigating these populations in disease. Reyka Chakravarthy¹, Kazuya Masuda¹, Monique M. Waldman¹, Alexander Kaminsky¹, Ionna M. Karantza¹, Moriya Tsuji², Annemieke de Jong¹ 1. Dermatology, Columbia University, New York, NY, United States. 2. 2ADARC, Columbia University, New York, NY, United States. Adaptive and Auto-Immunity