In Vivo Efficacy of Recombinant Leukotactin-1 against Cyclophosphamide

Leukotactin-1 (Lkn-1), a human CC chemokine, has been demonstrated to induce chemotaxis of neutrophils, monocytes, eosinophils and Iym phocytes and has been shown to suppress colony formation of hematopoietic stem and progenitor cells (HSPC) in vitro and in vivo. The temporal suppression of HSPC by chemokines could potentially be applicable for various indications, such as the protection of HSPC from the several anti-proliferating chemotherapeutics in cancer treatments. In order to evaluate the protective effects on myeloid progenitor cells, the recombinant Lkn-1 was produced by Pichia pastoris and tested with cyclophosphamide, cytotoxic chemotherapeutics. The pretreatment of Lkn-1 increased the number of HSPC in bone marrow as well as the potency of resulting progenitor cells after the treatment of cyclophosphamide. Af-ter the first cycle of cyclophosphamide treatment these protections of HSPC correlated with the increased number of white blood cells and neutrophils in the peripheral blood. In lethal conditions created by the repeated administration of cyclophosphamide, the treatment of Lkn-1 enhanced the survival of mice, suggesting the potential use of Lkn-1 as the protective agent for HSPC from various cytotoxic insults.