Abstract Text: Dendritic Cells (DCs) play a crucial role in maintaining the balance between autoimmunity and tolerance. Harnessing the ability to induce a tolerogenic phenotype in DCs, known as TolDCs, holds great promise for restoring immune tolerance and managing autoimmune diseases. In this study, we generate human TolDCs through co-culture with autologous Natural Killer (NK) cells. We co-cultured monocyte derived DCs with autologous NK cells overnight at a 5:1 ratio. Following this, the cells were treated with either LPS or a media control for four hours before undergoing FACS sorting. DCs cultured alone were also sorted as controls. We characterized these DCs using a combination of functional assays, epigenomic profiling using ATAC-Seq, and transcriptomic profiling using RNA sequencing. The DC-NK co-culture induced a consistent tolerogenic phenotype in DCs compared to DCs cultured alone, including lower expression of costimulatory molecules (CD80, CD86, CD40 and MHC-II), as well as a consistent change in cytokine expression, with decreased IL1 and IL6 levels and increased IL10 levels in addition to increased activity of TCF and KLF transcription factors, with known roles in tolerance. Additionally, these NK co-cultured DCs compared to DCs cultured alone were anergic to LPS stimulation and induced blunted T cell responses. Results indicate that this reprogramming is induced at epigenomic level. Our findings provide compelling evidence supporting the regulatory role of NK cells through TolDC induction, holding significant promise for restoring immune tolerance and managing autoimmune diseases.
