GM-CSF-producing T helper cells: a distinct subset of T helper cells that acquire Th1 phenotype during the CNS inflammation.

Using scRNA-seq and CyTOF, we identified eight populations of antigen-experienced CD45RA-CD4+ T cells in blood of healthy donors, including a population of GM-CSF-producing Th cells (ThGM) that lacked expression of signature transcription factors and cytokines of established Th lineages. In addition to GM-CSF, human and mouse ThGM cells also expressed IL-2, TNF, IL-3 and CCL20. ThGM cells maintained their phenotype through several cycles of activation, but upregulated expression of T-bet and IFN-g upon exposure to IL-12 in vitro, and in the CNS of mice with autoimmune neuroinflammation. ThGM cells were encephalitogenic; T-bet was not required for their development, but it was required for their encephalitogenicity. These findings demonstrate that ThGM cells constitute a distinct population of Th cells with lineage characteristics. Overall design: 5 scRNAseq datasets were analyzed.