ScRNA-seq mouse splenocytes prior to and during blood-stage malaria infection.
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ABSTRACT: Blood-stage malaria infection induces differentiation of several effector CD4 + T subsets including Tfh and Th1 cells. The cues and microarchitectural niches required in secondary lymphoid organs for their formation were previously uncharacterised. Here we used scRNA-seq to profile splenocyte transcriptomes at steady state or upon malaria infection as a reference dataset for deconvolution of spatial transcriptomic data.
Project description:Blood-stage malaria infection induces differentiation of several effector CD4 + T subsets including Tfh and Th1 cells. The cues and microarchitectural niches required in secondary lymphoid organs for their formation were previously uncharacterised. Here we used scRNA-seq to profile CD4+ T cell transcriptomes upon malaria infection as a reference dataset for deconvolution of spatial transcriptomic data.
Project description:Blood-stage malaria infection induces differentiation of several effector CD4 + T subsets including Tfh and Th1 cells. The cues and microarchitectural niches required in secondary lymphoid organs for their formation were previously uncharacterised. Here we used spatial transcriptomics to characterise the microarchitecture of mouse spleen before and during malaria infection, and mapping the spatial and molecular requirements of Tfh/Th1 differentiation.
Project description:T-follicular CD4 T (Tfh) cells play essential roles in antibody induction during infection and following vaccination. In humans, peripheral Tfh (pTfh) cells are commonly analysed based on expression of CXCR3 and CCR6, with different subsets of pTfh (pTfh1, pTfh2, pTfh17) associated with antibody induction in a context-dependent manner. In malaria, the specific roles of pTfh subsets in antibody development is not clear. Several studies in human malaria infection and vaccination have identified an important role of pTfh2 cells, which associate with antibody development while pTfh1 cells do not. However, in vitro studies and animal models highlight that pTfh1 cells are key drivers of cytophilic antibody development, which are protective. To dissect these contradictions, we mapped the heterogeneity of pTfh cells in healthy individuals and individuals with controlled human malaria infection using scRNAseq. We identified two, previously unidentified, pTfh1-like subsets with functional relevance, which can be defined based on CCR7 expression. CCR7pos pTfh1 cells have increased capacity to produce IL-21, whereas CCR7neg pTfh1 cells express markers of cytotoxicity. In controlled human malaria infection, we show that both CCR7pos and CCR7neg pTfh1 cells, along with Tfh2 cells, clonally expand, are transcriptionally and phenotypically activated, and are malaria specific. However, only CCR7pos pTfh1 and pTfh2 cells associated with antibody responses to infection. Our data advance our knowledge of Tfh cell diversity, and may inform the development of vaccines and therapeutics that target these key CD4 T cell responses.
Project description:Naturally-acquired immunity to blood-stage malaria is associated with several effector CD4 + T subsets including germinal centre (GC) Tfh, Th1 and Tr1 cells. Children in malaria-endemic regions can experience repeated Plasmodium infections over short periods of time; yet the effect of reinfection on multiple co-existing effector and memory subsets remains unclear. Here, we tracked antigen-experienced polyclonal CD4+ T cells during Plasmodium re-infection in mice using scRNA-seq/TCR-seq.
Project description:Naturally-acquired immunity to blood-stage malaria is associated with several effector CD4 + T subsets including germinal centre (GC) Tfh, Th1 and Tr1 cells. Children in malaria-endemic regions can experience repeated Plasmodium infections over short periods of time; yet the effect of reinfection on multiple co-existing effector and memory subsets remains unclear. Here, we tracked antigen-experienced TCR-transgenic CD4+ T cells during Plasmodium re-infection in mice using scRNA-seq.
Project description:Blood-stage malaria initiates both innate and adaptive immune responses, inclusive a strong activation of the mononuclear phagocyte network. Here we show that Plasmodium infection results in a transient loss of embryonically established tissue-resident macrophages in spleen, liver and lungs, much before the peak of parasitemia. During acute blood-stage malaria, fate mapping analysis revealed that inflammatory monocytes contribute to the repopulation of the emptied niches of splenic red pulp macrophages and hepatic Kupffer cells, while lung alveolar macrophages refill their niche mainly through self-renewal. Interestingly, the local microenvironment of spleen and liver can “imprint” the molecular characteristics of fetal-derived macrophages in new immigrants from bone marrow including almost identical gene expression profiles and turnover kinetics.
Project description:Using genome-wide expression profiles from persons either experimentally challenged with malaria-infected mosquitoes or naturally-infected with Plasmodium falciparum malaria, we present details of the transcriptional changes that occur with infection and that are either commonly shared between subjects with pre-symptomatic and clinically apparent malaria or that distinguish these two groups. Our findings confirm and extend aspects of the earliest responses to malaria infection at the molecular level and which may be informative in elucidating how innate and adaptive immune responses may be modulated in different stages of infection. Keywords: Human PBMC samples from natural and experimentally (clinical trial) induced malaria
Project description:Cerebral malaria (CM) is one of the most severe complications of malaria infection. There is evidence that repeated parasite exposure promotes resistance against CM, as indicated by the low incidence of CM in adults in malaria-endemic regions. However, the immunological basis of this infection-induced resistance remains poorly understood. Here, a microarray study done utilising the tractable Plasmodium berghei ANKA model of experimental cerebral malaria (ECM), we show that three rounds of infection and drug-cure protects against the development of ECM during a subsequent fourth infection.