TNF signalling drives expansion of bone marrow CD4+ T cells responsible for HSC exhaustion in experimental visceral leishmaniasis

PLoS Pathogens

Olivier Preham¹  Najmeeyah Brown¹  Johannes S. P. Doehl¹  Helen Ashwin¹  Paul M. Kaye¹  Ana Isabel Pinto¹ 

[1] Centre for Immunology and Infection, Dept. of Biology and Hull York Medical School, University of York, Heslington, York, United Kingdom

关键词: T cells;    Leishmania donovani;    Parasitic diseases;    Spleen;    Cell differentiation;    Hematopoiesis;    Cytokines;    Bone marrow cells;   

DOI  :  10.1371/journal.ppat.1006465

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Visceral leishmaniasis is associated with significant changes in hematological function but the mechanisms underlying these changes are largely unknown. In contrast to naïve mice, where most long-term hematopoietic stem cells (LT-HSCs; LSK CD150+ CD34- CD48- cells) in bone marrow (BM) are quiescent, we found that during Leishmania donovani infection most LT-HSCs had entered cell cycle. Loss of quiescence correlated with a reduced self-renewal capacity and functional exhaustion, as measured by serial transfer. Quiescent LT-HSCs were maintained in infected RAG2 KO mice, but lost following adoptive transfer of IFNγ-sufficient but not IFNγ-deficient CD4+ T cells. Using mixed BM chimeras, we established that IFNγ and TNF signalling pathways converge at the level of CD4+ T cells. Critically, intrinsic TNF signalling is required for the expansion and/or differentiation of pathogenic IFNγ+CD4+ T cells that promote the irreversible loss of BM function. These findings provide new insights into the pathogenic potential of CD4+ T cells that target hematopoietic function in leishmaniasis and perhaps other infectious diseases where TNF expression and BM dysfunction also occur simultaneously.

【 授权许可】

CC BY