Modulation of leukocyte recruitment through intervention with chemokine receptors is an attractive, therapeutic strategy. Recently, we have shown that n-Nonanoyl (NNY)-CCL14 internalizes and desensitizes human (h)CCR3, resulting in the inactivation of eosinophils. In this study, we investigated the interaction of NNY-CCL14 with CCR1 and CCR5 and the relevance of these NNY-CCL14 receptors on its in vivo effects in allergic airway inflammation. NNY-CCL14 has inactivating properties on CCR1(+) and CCR5(+) cell lines and primary leukocytes. It desensitizes hCCR1- and hCCR5-mediated calcium release and internalizes these receptors from the cellular surface. Treatment of OVA-sensitized BALB/c mice with NNY-CCL14 resulted in reduced pulmonary inflammation. Above all, it is demonstrated that systemic treatment with NNY-CCL14 down-modulates CCR5 from the surface of lymphocytes in vivo. Although NNY-CCL14 acts on murine lymphocytes and internalizes CCR5, it does not internalize CCR3 on mouse eosinophils, showing species selectivity regarding this particular receptor. Therefore, the inhibitory effects of NNY-CCL14 in murine models of allergic airway inflammation can be assigned to its interaction with CCR5. The presented results substantiate the relevance of CCR5 as a target for allergic airway inflammation.