Characterization of human CD34+ HSPC-derived neutrophils with limited myeloid-derived immunosuppressive cell activity

Neutrophils have limited utility as a fundamental research model and transfusion product due to their short lifespan. Here, we cultured CD34+ hematopoietic stem and progenitor cell (HSPC)-derived neutrophils and compared them to peripheral blood neutrophils in terms of morphology, phenotype, and function. Our culture system resulted in morphologically mature CD15+CD11b+CD16high neutrophils with effector functions almost indistinguishable from blood neutrophils, confirmed by a high similarity in transcription and protein abundance patterns. While exhibiting microbial killing capacity and antibody-dependent cellular cytotoxicity, these cells were deficient in myeloid-derived suppressor cell activity. This deficiency in immunosuppressive activity correlated with a distinct granular composition in comparison to blood neutrophils, instead of immunosuppressive characteristics that are currently held to define neutrophil-MDSC phenotype. Taken together, our cultured neutrophils closely resemble blood neutrophils, offering a repository for fundamental research and a step toward an effective transfusion product with limited immunosuppressive activity as a functional property. Overall design: Bulk RNAseq profiling of HSC-derived neutrophils cultured in SL-II medium at Day0, Day10, Day14 and Day17 of maturation. At day 14 and day 17 these cells were MACS sorted for CD16+ creating positive, negative and bulk fractions. PMNs and IMDM derived neutrophils at the endstage were included.