Identification of human neutrophils during experimentally induced inflammation in mice with transplanted CD34+ cells from human umbilical cord blood.

Nonobese diabetic/severe combined immunodeficiency/gamma chainnull (NOG) mice are excellent recipients for xenotrans-plantation and have been especially valuable for the evaluation of human hematopoietic stem cell (HSC) activities. Because human hematopoietic cells that developed in this mouse were mainly lymphoid cells and not myeloid cells, mature human myeloid cells such as neutrophils were hardly detectable in peripheral blood. We demonstrated that human neutrophils accumulated by means of a zymosan-induced air pouch inflammation technique could be identified with a fluorescence-activated cell sorter in NOG mice with transplanted CD34+ cells from human umbilical cord blood, which were putative hematopoietic progenitor cells including HSC. Our results indicate that human neutrophils with a chemotactic capacity can develop from human hematopoietic progenitor cells in vivo, suggesting that our system may be a useful tool for the evaluation of human HSC activities.