Plasmodium yoelii infection inhibits murine leukaemia WEHI-3 cell proliferation in vivo by promoting immune responses

Zhen-Zhen Tong,Xiao Hou,Wan-Fang Jiang,Zheng-Ming Fang,Yun Zhan,Yong-Long Li,Qi Zhang,Yue Zhang,Ting Wang

doi:10.1186/s40249-018-0433-4

Zhen-Zhen Tong, Xiao Hou + Show 7 more

Open Access

https://doi.org/10.1186/s40249-018-0433-4

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Abstract

BackgroundLeukaemia is a malignant leukocyte disorder with a high fatality rate, and current treatments for this disease are unsatisfactory. Therefore, new therapeutic strategies for leukaemia must be developed. Malaria parasite infection has been shown to be effective at combating certain neoplasms in animal experiments. This study is to demonstrate the anti-leukaemia activity of malaria parasite Plasmodium yoelii (P. yoelii) infection,.MethodsIn this study, the proportion of CD3, CD19, CD11b and Mac-3 cells was analysed by flow cytometry; the levels of IFN-γ and TNF-α in individual serum samples were measured by enzyme-linked immunosorbent assay, and the phagocytic activity of macrophages and natural killer (NK) cell activity were measured by flow cytometry.ResultsWe found that P. yoelii infection significantly attenuated the growth of WEHI-3 cells in mice. In addition, tumor cell infiltration into the murine liver and spleen was markedly reduced. We also demonstrated that malaria parasite infection elicited anti-leukaemia activity by promoting immune responses, including increasing the surface markers of T cells (CD3) and B cells (CD19); decreasing the surface markers of monocytes (CD11b) and macrophages (Mac-3); inducing the secretion of IFN-γ and TNF-α; and increasing NK cell and macrophage activity.ConclusionsMalaria parasite infection significantly decreases the number of myeloblasts and inhibits neoplasm proliferation in mice. In addition, malaria parasite infection inhibits murine leukaemia by promoting immune responses.

Highlights

Leukaemia is a malignant leukocyte disorder with a high fatality rate, and current treatments for this disease are unsatisfactory
Bone marrow smear and histopathological examination Analysis of bone marrow smears showed that myeloblasts were present in the bone marrow of all mice (Fig. 1), but the percentage of myeloblasts in the mice inoculated with WEHI-3 cells was much higher than that in the mice of other groups (P < 0.001) (Fig. 2)
In the WEHI-3 group, abundant neoplastic cells were found in liver and spleen tissues (Fig. 3), whereas the number of these cells were markedly reduced in the WEHI-3 + Py group (P < 0.01 and P < 0.001 compared with the liver (Fig. 4a) and WEHI-3 group (Fig. 5), indicating that malaria parasite infection could increase natural killer (NK) cell cytotoxicity in WEHI-3 cell-bearing mice

Summary

Introduction

Leukaemia is a malignant leukocyte disorder with a high fatality rate, and current treatments for this disease are unsatisfactory. This study is to demonstrate the anti-leukaemia activity of malaria parasite Plasmodium yoelii (P. yoelii) infection,. Several researchers have reported an adverse relationship between parasitic infections and cancer. Parasitic infections, such as Trypanosoma cruzi [3], Toxoplasma gondii [4], Trichinella spiralis [5, 6], Toxocara canis [7], Acanthamoeba castellanii [8] and Plasmodium yoelii infections [9], have reportedly inhibited cancer growth in animal experiments. The adverse relationship between parasitic infections and cancer in humans has been demonstrated in epidemiological investigations of the prevalence of parasitic infections and cancer diseases [10]. In 1980, statistical data from the WHO indicated that the incidence of cancer was lowest in malaria-endemic areas [11]

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