The CXC-chemokines interleukin-8 (IL-8), neutrophil-activating peptide- 2 (NAP-2), and melanoma growth-stimulatory activity (MGSA) are chemoattractants with high selectivity for neutrophils. Although IL-8 has been shown to act as an extremely potent mediator, reports on NAP-2 and MGSA are still contradictory. Here we show for the first time that NAP2 and MGSA induce two distinct optima of neutrophil chemotaxis. A first optimum is elicited within a concentration range as low as it is characteristic for IL- 8. However, a second optimum appears at more than 200-fold higher stimulus concentrations, at which IL-8 is inactive. Investigating the involvement of the two chemokine receptors CXCR-1 and CXCR-2 in NAP-2-mediated chemotaxis, we observe that the cells become desensitized to the first optimum of the chemokine after selective downregulation of CXCR-2, while both optima disappear upon simultaneous downregulation of both receptors. Blocking monoclonal antibodies (MoAbs) specific for CXCR-2 or CXCR-1 either suppress the first optimum of NAP-2-induced chemotaxis or drastically reduce the second one, respectively. These results provide evidence that both receptors are involved in NAP-2-induced neutrophil chemotaxis, with CXCR-2 rendering the cells responsive to low dosages of the chemokine, and with CXCR-1 extending their responsiveness to NAP-2 dosages higher by several orders of magnitude.
CITATION STYLE
Ludwig, A., Petersen, F., Zahn, S., Götze, O., Schröder, J. M., Flad, H. D., & Brandt, E. (1997). The CXC-chemokine neutrophil-activating peptide-2 induces two distinct optima of neutrophil chemotaxis by differential interaction with interleukin- 8 receptors CXCR-1 and CXCR-2. Blood, 90(11), 4588–4597. https://doi.org/10.1182/blood.v90.11.4588.4588_4588_4597
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