Phagocytic activity of neutrophil is induced by granulocyte colony stimulating factor and interleukin-15 in leukemic animal model

•Phagocytosis activity of neutrophil is improved after G-CSF + IL-15 treatment in leukemia.•TLR4 expression is reduced in leukemia but improved after G-CSF + IL-15 treatment.•TLR9 expression is reinstated after G-CSF + IL-15 treatment in Leukemic animal.

In leukemia, secondary infection is common and after chemotherapy the number of normal active neutrophil reduced significantly. Therefore, to avoid side effects of chemotherapy and to induce neutrophil activity and number, in this study, we have treated with G-CSF plus IL-15 in combination to N–N′ Ethylnitrosourea (ENU) induced leukemia in BALB/c mice. After 5 months of ENU treatment in 3–4 weeks old mice at 80 mg/kg body weight, leukemia was confirmed by histology of blood smear co-treatment started with cytokines for 5 days. The in vitro phagocytosis activity of neutrophil from spleen was assayed using Dalton's lymphoma ascites as target cell. Using real time polymerase chain reaction (RT-PCR), Toll like receptor 4 (TLR4) and toll like receptor 9 (TLR9) expression of neutrophil was also measured. Our data suggests that G-CSF plus IL-15 induce the phagocytic activity of neutrophil. TLR4 and TLR9 expression was induced in neutrophil after treatment with cytokines together which was significantly reduced in leukemia. In conclusion, G-CSF plus IL-15 has potential role as therapeutic immunomodulators for neutrophil activity in leukemia.