IL-27 production by splenic immune cells throughout persistent LCMV infection

The pleiotropic cytokine IL-27 is essential for the clearance of the persistent LCMV strain Clone 13, however the cellular sources of IL-27 during viral infection are incompletely mapped and their relative importance unknown. Here we utilised single-cell RNA-sequencing of splenocytes from IL27-p28-GFP mice infected with Clone 13 to quantify the temporal patterns of IL-27 p28 production. IL-27-p28-GFP+ and IL-27-p28-GFP- splenocytes were sorted at 4 timepoints during Clone 13 infection and analysed by 3' single-cell transcriptome sequencing. Dendritic cells were major producers of early IL-27 with macrophages and monocytes being the predominant IL-27 producers during acute and persistent phases of infection. Interestingly, we also identified activated B cells and plasma cells as a prominent subset of IL-27-producing splenocytes and through B-cell-specific deletion of IL-27-p28 demonstrated that B-cell derived IL-27 is essential for sustained function of CD4 T cells and eventual clearance of Clone 13. Overall design: IL-27-p28-GFP+ and IL-27-p28-GFP- splenocytes from Tg(Il27-Gfp) reporter mice infected with LCMV Clone 13 were subjected to 3' single-cell transcriptome sequencing.