Single cell transcriptome profiling illuminates conserved anti-bacterial neutrophil state evoked by IFNr signaling

Streptococcus agalactiae, a significant cause of mortality and morbidity worldwide, is characterized by the recruitment and activation of immune cells. Although, relevant studies have been conducted at the population level, systematic analysis of post-infection immune cell dynamics at the single-cell level is required. In particular, little is known about the neutrophils state transition of teleost during infection. Here, we generated single-cell immune cells transcriptomic profiling from head kidney and spleen of Nile tilapia at different time points (0, 1, 5,10, 75, and 3-2nd dpi) after Streptococcus agalactiae infection. Four prime immune cells, including neutrophils, macrophages, T cells, and B cells, exhibited extraordinary complexity and dynamic states. Notably, il8+ neutrophils were associated with anti-bacterial function during infection process and could be evoked by IFNr signaling, which was conserved in human and teleost. In summary, these data not only indicate immune cell orchestrated maturation states during bacterial infection but also suggest therapeutic opportunities such as IFNr signaling delivery for bacterial infection in teleost.