The Antitumor Effect Of Irradiated Haploidentical Donor Lymphocyte Infusion On Mice With Melanoma

Object：Donor lymphocyte infusion (DLI) as an effective method for adoptivecellular immunotherapy (ACI), which is often combined with hematopoietic stem celltransplantation, has provided a new approach for the treatment of hematologicalmalignancies and some solid tumors, with the potential for more precise targetingand reduced toxicity.This study discusses the anti-tumor effect on mice withmelanoma and possibly involved mechanism of haploidentical donor lymphocyteinfusions in CB6F1mice�'CC3HF1mice (F1�'F1) mouse model.Methods：F1-F1haploidentical infusion model was establishd. CB6F1mice (H-2b/d)were subcutaneously inoculated with B16-F10cells to develop melanoma model thatwas taken as recipients.CC3HF1mice (H-2d/k) was used as donors. All the mice weredivided into four groups: PBS groups (mice received a intravenous of PBS), CTXgroups (mice received a intravenous of PBS after a intraperitoneal ofcyclophosphamide), CTX+T cell groups (mice received the irradiated T cells ofsplenocytes after a intraperitoneal of cyclophosphamide); CTX+spleen cell groups(mice received the irradiated splenocytes after a intraperitoneal of cyclophosphamide).Tumor volume, body weight, survival time and tumor weight of each group weremonitored. Flow cytometry was used to analyze the survival time of donorlymphocytes and the changes of host-derived lymphocytes subset. The killing effectof host splenocytes was detected by LDH after irradiated haploidentical lymphocytesinfusion. The concentration of the IL-2and IFN-γ in serum were measured usingspecific ELISA kit for mouse IL-2and IFN-γ. GVHD (graft versus host disease) wasalso monitored by the GVHD-related symptoms and confirmed by histopathologicalexamination of important organs.Results：There were no significantly statistical differences between group PBS and group CTX about tumor volume, the median survival time and tumor weight, so weregroup CTX+T cell and group CTX+spleen cell (P>0.05). The tumor was significantlysuppressed in group CTX+T cell and group CTX+spleen cell comparing with groupPBS(8.07±1.66cm3、8.24±1.45cm3vs.10.84±1.11cm3, P <0.05), so was the tumorweight (8.19±0.82g、7.62±0.94g vs.12.38±2.73g, P <0.05). The median survival timein group CTX+T cell and group CTX+spleen cell is longer than the PBS group(31±3.286d、36±2.191d vs.19±0.548d, P <0.05). GVHD was not obvious in anygroup after DLI treatment. The donor lymphocytes cells were rejected anddisappeared within5days after infusion. Surprisingly, anti-tumor effect was stillobserved after then. Moreover, the group after DLI treatment could effectivelyincrease the levels of cytokine including IFN-γ and IL-2, and enhance theproliferation of CD8+T lymphocytes and NK cells.Conclusion：Infusion of irradiated haploidentical donor lymphocyte after low doesCTX can induce anti-tumor effect on mice with melanoma in F1�'F1infusion model.DLI can induce HVT effect and enhance the proliferation of CD8+lymphocyte Tcells and NK cells significantly. At the same time, it can also increase the secretion ofcytokine including IFN-γ and IL-2. Donor T cells is crucial for this anti-tumor effect.