Enhancement of interleukin-8-induced chemotactic response and reactive oxygen species production in HL-60 cells expressing CXCR1

Neutrophils play a pivotal role in immunity against infection by ingesting and killing invading microbes. Neutrophils isolated from human peripheral blood have been used for a number of studies conducted for evaluation of immunomodulating drugs, cytokines, and microbe products. Human promyelocytic leukemia cells, HL-60, have been extensively studied because they can differentiate into neutrophil-like cells by addition of all-trans retinoic acid or dimethyl sulfoxide. For a system that would always allow experimental use of granulocytic cells in a uniformly activated state, we have established HL-60 cell lines with increased migratory activity by transducing the CXC chemokine receptor 1 (CXCR1) gene. When these cell lines were primed with CXC chemokine ligand 8 (IL-8), a slight increase in reactive oxygen species production induced by phorbol myristate acetate (PMA) or zymosan A stimuli was observed. A significance increase in migratory activity was noticed when the HL-60 cells transduced CXCR1 were stimulated with IL-8 in the Boyden chamber method. The gene-transduced HL-60 cell lines may be used as a substitute for neutrophils in screening the effects of various immunomodulating drugs on the migratory activity induced by IL-8.