Multiplexed, Sequential Secretion Analysis of the Same Single Cells Reveals Distinct Effector Response Dynamics Dependent on the Initial Basal State

The effector response of immune cells is a highly dynamic process. To explore time course of human macrophage response to toll-like receptor 4 (TLR4) ligand, human U937 cell line-derived macrophages were stimulated with lipopolysaccharide (LPS) and single-cell RNA-Sequencing were conducted at 0, 2, 4 and 6 hours after the initial treatment. The data demonstrated the existence of two major activation states at the transcriptional level, which were enriched for translation versus inflammatory programs, respectively. These results show a cell-intrinsic heterogeneous response in a phenotypically homogeneous cell population, providing dynamic information to better understand how immune cells react to pathogenic challenges over time and how they together constitute a population response. Examination of 4 time points (0, 2, 4 and 6 hours) upon LPS activation in human U937-derived macrophages