Plasmodium berghei ANKA infection increases Foxp3, IL-10 and IL-2 in CXCL-10 deficient C57BL/6 mice

Abstract Background Cerebral malaria (CM) is a major cause of malaria mortality. Sequestration of infected red blood cells and leukocytes in brain vessels coupled with the production of pro-inflammatory factors contribute to CM. CXCL-10 a chemokine that is chemotactic to T cells has been linked to f...

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Bibliographic Details
Published in:Malaria Journal
Main Authors: Stiles Jonathan K, Bond Vincent C, Wilson Nana O, Sarfo Bismark Y
Format: Article in Journal/Newspaper
Language:English
Published: BMC 2011
Subjects:
Online Access:https://doi.org/10.1186/1475-2875-10-69
https://doaj.org/article/9cb2786e4c294d70b8ef1cd9d93cc917
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Summary:Abstract Background Cerebral malaria (CM) is a major cause of malaria mortality. Sequestration of infected red blood cells and leukocytes in brain vessels coupled with the production of pro-inflammatory factors contribute to CM. CXCL-10 a chemokine that is chemotactic to T cells has been linked to fatal CM. Mice deficient for CXCL-10 gene are resistant to murine CM, while antibody ablation of CXCL-10 enhanced the production of regulatory T cells (CD4+Cd25+Foxp3+) and IL-10 which regulate the immune system. Interleukin-2 (IL-2), a pro-inflammatory cytokine implicated in malaria pathogenesis has also been shown to be a key regulator of Foxp3. However the role of Foxp3 in resistant murine CM is not well understood. Methods The hypothesis that resistance of CXCL-10-/- mice to murine CM may be due to enhanced expression of Foxp3 in concert with IL-10 and IL-2 was tested. CXCL-10-/- and WT C57BL/6 mice were infected with Plasmodium berghei ANKA and evaluated for CM symptoms. Brain, peripheral blood mononuclear cells (PBMCs) and plasma were harvested from infected and uninfected mice at days 2, 4 and 8. Regulatory T cells (CD4+CD25+) and non-T regs (CD4+CD25-) were isolated from PBMCs and cultured with P. berghei antigens in vitro with dendritic cells as antigen presenting cells. Regulatory T cell transcription and specific factor Foxp3, was evaluated in mouse brain and PBMCs by realtime-PCR and Western blots while IL-10, and IL-2 were evaluated in plasma and cultured supernatants by ELISA. Results Wild type mice exhibited severe murine CM symptoms compared with CXCL-10-/- mice. Foxp3 mRNA and protein in brain and PBMC's of CXCL-10-/- mice was significantly up-regulated (p < 0.05) by day 4 post-infection (p.i) compared with WT. Plasma levels of IL-10 and IL-2 in infected CXCL-10-/- were higher than in WT mice (p < 0.05) at days 2 and 4 p.i. Ex-vivo CD4+CD25+ T cells from CXCL-10-/- re-stimulated with P. berghei antigens produced more IL-10 than WT CD4+CD25+ T cells. Conclusion The results indicate that in the ...