Biology subjects

Engwerda, C.

Publications and source records attributed to Engwerda, C..

9 recordsLinked to original sources

bioRxiv2026

Circulating T-follicular helper and type I regulatory T cells have overlapping phenotypes in P. falciparum malaria and are maintained by parasite exposure.

Immunity to P. falciparum malaria develops slowly, requiring repeated infection in areas of high transmission, and wanes rapidly in the absence of parasite exposure. Key to this immunity, is the development of antibodies which is supported by CD4 T follicular helper (Tfh) cells that drive robust germinal centre responses. However, in malaria, the malaria-specific CD4 T cell compartment in peripheral blood is dominated by Type 1 regulatory T cells (Tr1), which produce high levels of IL-10 in response to parasites. Tr1-like Tfh cells (Tfh10) have been reported in several settings of repeated antigen stimulation but have not been investigated in malaria. Here we used single-cell RNA sequencing and multiparameter flow cytometry to characterise malaria-specific Tfh and Tr1 cells in a longitudinal cohort of highly exposed individuals and assessed their persistence after transmission interruption. Malaria-specific Tfh and Tr1 cells shared overlapping profiles, and Tr1 cell-like transcriptional signatures and phenotypes were detectable within the Tfh cell compartment. Tfh10 cell subsets were the dominant phenotype of malaria-specific Tfh cells. Following disruption of malaria transmission, the frequencies of malaria-specific Tr1 and Tfh10 cells declined. These findings highlight a close relationship between Tfh and Tr1 cells and show that the Tfh cell compartment in malaria is dominated by Tfh10 cells. The rapid waning of these cells in the absence of continuous exposure is consistent with requirements of persistent antigen in maintaining regulatory CD4 T cell phenotypes.

immunology↗

bioRxiv2025

Myeloid HDAC7 drives liver inflammation and systemic glucose dysregulation during diet-induced obesity

ObjectivesHistone deacetylase 7 (HDAC7), a classical HDAC family member, promotes LPS-inducible glycolysis and inflammatory mediator production in macrophages, innate immune cells that contribute to pathology in metabolic diseases. Here, we investigated myeloid HDAC7 functions in obesity-driven metabolic disease. MethodsWe used gain- and loss-of-function genetic approaches in mice to investigate myeloid HDAC7 functions in hepatic inflammation and metabolic disease, as well as associations with hepatic gene signatures characteristic of advanced chronic liver disease (CLD). ResultsTransgenic expression of Hdac7 in myeloid cells increased liver inflammation and liver mRNA levels of Ccl2 and Il1b, key inflammatory mediators linked to CLD. Liver glycogen levels were also decreased, another feature of CLD. Transgenic expression of Hdac7 in myeloid cells mimicked the hepatic inflammatory phenotype that was observed in mice fed a high fat, high cholesterol, and high sucrose (HFHCHS) diet, an obesity model that mimics some features of metabolic dysfunction-associated steatotic liver disease. In myeloid Hdac7 transgenic mice fed a HFHCHS diet, relative weight gain was increased, fasted glucose levels were elevated and glucose tolerance was dysregulated by comparison to control mice. Conversely, fasted blood glucose levels were reduced and glucose tolerance was improved in myeloid Hdac7-deleted mice on a HFHCHS diet. HDAC7 mRNA levels were also elevated in the livers of people with advanced CLD and spatial transcriptomics revealed that myeloid HDAC7 directs hepatic gene signatures characteristic of advanced CLD. ConclusionsMyeloid HDAC7 contributes to hepatic inflammation and systemic glucose dysregulation in a mouse model of obesity and liver inflammation.

immunology↗

bioRxiv2025

Comparison of CD4 T cell response in Plasmodium falciparum and vivax malaria

BackgroundPlasmodium falciparum and P. vivax are parasites responsible for most malaria cases globally. In areas where these species co-exist, individuals gain protection from P. vivax more rapidly, and important biological differences between species may impact the immune response. CD4 T cells are key drivers of immunity to malaria, both as effector and helper cells, with T-follicular helper (Tfh) having key roles in antibody development. Comparative studies on CD4 T cell responses between these species are limited. MethodsWe assessed CD4 T cells in adults with either P. falciparum or P. vivax malaria. Activation and proliferation of CD4 T cells were measured ex vivo, and functional capacity determined by intracellular cytokine staining by flow cytometry. ResultsThe phenotype, activation and proliferation of CD4 T cells and effector CD4 T cell subsets were comparable between species. However, within the peripheral (p)Tfh cell compartment, there was evidence for a skew towards pTfh1 cells in P. falciparum, and pTfh2 cells in P. vivax. Additionally, in P. falciparum, increased IL-10 production was detected, including within IL-21 producing CD4 T cells. ConclusionWhile activation and function of CD4 T cells in malaria are largely comparable, some species-dependent responses are detected within the pTfh cell compartment that may impact antibody development.

immunology↗

bioRxiv2025

Tissue-specific improvements in CD4+ T cell responses after treatment for visceral leishmaniasis.

Visceral leishmaniasis (VL) is a life-threatening parasitic disease that requires robust CD4+ T cell-mediated immunity for parasite control. However, the heterogeneity and transcriptional dynamics of CD4+ T cell responses in VL remain poorly defined. In this study, we use a model of experimental VL with tissue-specific immunity and single-cell RNA sequencing to provide a high-resolution assessment of CD4+ T cell responses. Our analysis reveals the complexity of CD4+ T cell differentiation in VL, identifying distinct Th1 subsets with transcriptional heterogeneity that may reflect functional specialisation. Despite minimal transcriptional differences between splenic and hepatic CD4+ T cells, we identified shifts in subset composition, including the emergence of a stem-like CD4+ T cell population in the spleen, which was suppressed by the transcription factor Bhlhe40. Bhlhe40 deficiency skewed CD4+ T cell differentiation, impairing Th1 responses while promoting Tr1 cells, resulting in defective parasite control in the liver. Additionally, AmBisome treatment induced a profound transcriptional shift in CD4+ T cells, leading to the maintenance of stem-like CD4+ T cells in the spleen and the expansion of tissue resident memory-like cells in the liver. These findings uncover key regulatory mechanisms that shape CD4+ T cell differentiation in VL and provide insights into how immune-modulatory strategies could enhance long-term immunity.

immunology↗

bioRxiv2025

CCR7 Expression Distinguishes Functionally Distinct pTfh1 Subsets with Roles in Malaria-Specific Immunity

Antibodies induced by infection or vaccination are essential mediators of protection. Induction of these protective responses is mediated by T-follicular CD4 T (Tfh) cells, and targeting these cells may be a strategy to boost antibody mediate protection. In humans, Tfh cells are analysed based on expression of CXCR3 and CCR6, with different subsets of Tfh (Tfh1, Tfh2, Tfh17) associated with antibody induction in a context-dependent manner. Here we dissected Tfh cells heterogeneity in healthy donors and individuals during controlled human malaria infection using scRNAseq. We identified two distinct Tfh1-like subsets with functional relevance, defined based on CCR7 expression. CCR7neg Tfh1 cells express markers of cytotoxicity, while CCR7pos Tfh1 cells produce reduced inflammatory cytokines and similar IL-21 resulting in unique cytokine milieu. In controlled human malaria infection, both CCR7pos and CCR7neg Tfh1, along with Tfh2 cells, clonally expanded and were transcriptionally and phenotypically activated. However, only CCR7pos Tfh1 and Tfh2 cells associated with antibody development, suggesting a role for both these Tfh subsets in promoting humoral immunity to malaria. Data identify specific protective Tfh subsets that can be targeted to improve antibody mediated protection to malaria induced, and provide a frame work to dissect the role of Tfh subsets in other disease contexts.

immunology↗

bioRxiv2024

Age is an intrinsic driver of inflammatory responses to malaria

Age is a critical factor influencing the host immune response to infection and disease pathogenesis. In malaria, the risk of severe disease increases with age in non-immune individuals. Malaria severity is in part driven by inflammation, but the specific cells and mechanisms contributing to age-dependent disease risk are incompletely understood. Here, we assessed inflammatory cytokines in non-immune children and adults with clinical malaria, and the phenotypic, functional and transcriptional differences of in vitro innate cell responders to malaria parasites in naive children and adults. During naturally acquired malaria, age was associated with increased plasma levels of inflammatory chemokines CCL2, CCL3, CXCL8, CXLC9, along with CRP, and IDO, which were associated with clinical symptoms. In malaria naive individuals, classical monocyte and V{delta}2+ {gamma}{delta} T cell responses from adults were characterized by higher inflammatory cytokine production, and transcriptional activation following stimulation with malaria parasites. Classical monocyte responses in adults were dominated by CCL2 production, while in children the response had increased IL10 production and enrichment in IL10 signaling pathways upon parasite stimulation. This heightened inflammatory response in adults was not mitigated by parasite induced Tregs. Taken together, these findings identify cellular mechanisms of age-dependent host responses that play crucial roles in driving inflammatory responses in malaria.

immunology↗

bioRxiv2024

Latent cytomegalovirus is associated with reduced functional antibody induction following Plasmodium falciparum infection

Human immune responses to infection and vaccination are heterogenous, driven by multiple factors including genetics, environmental exposures and personal infection histories. For malaria caused by Plasmodium falciparum parasites, host factors that impact on humoral immunity are poorly understood. We investigated the role of latent cytomegalovirus (CMV) on the host immune response to malaria using blood stage P. falciparum Controlled Human Malaria Infection (CHMI) and in a MSP1 vaccine Phase 1a clinical trial. CMV seropositivity was associated with reduced induction of parasite specific antibodies following malaria infection and vaccination. During infection, reduced antibody induction was associated with modifications to the T -follicular helper (Tfh) cell compartment. CMV seropositivity was associated with a skew towards Tfh1 cell subsets before and after malaria infection, and reduced activation of Tfh2 cells. Protective Tfh2 cell activation was only associated with antibody development in CMV seronegative individuals, and a higher proportion of Tfh1 cells was associated with lower antibody development in CMV seropositive individuals. During MSP1 vaccination, reduced antibody induction in CMV seropositive individuals was associated with CD4 T cell expression of terminal differentiation marker CD57. These findings are particularly relevant for malaria endemic regions where CMV infection is acquired early in life and may modify immunity to malaria gained during infection or vaccination.

immunology↗

bioRxiv2022

STING activation promotes autologous type I interferon-dependent development of type 1 regulatory T cells during malaria

The development of highly effective malaria vaccines and improving drug treatment protocols to boost anti-parasitic immunity is critical for malaria elimination. However, these efforts are hampered by parasite-specific immunoregulatory networks that are rapidly established following exposure to malaria parasites. Here, we identify stimulator of interferon genes (STING) as a critical mediator of type I interferon production by CD4+ T cells during blood-stage Plasmodium falciparum infection. STING activation by cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) stimulated IFNB gene transcription that promoted development of IL-10 and IFN{gamma} co-producing CD4+ T (type I regulatory; Tr1) cells. CD4+ T cell sensitivity to STING phosphorylation increased in healthy volunteers following P. falciparum infection, particularly in Tr1 cells. Finally, we found the JAK1/2 inhibitor ruxolitinib modulated this innate signalling axis in CD4+ T cells to increase parasite-specific Th1 and diminish Tr1 cell responses. These findings identify STING as a critical mediator of Tr1 cell development during malaria.

immunology↗

bioRxiv2020

Th2-like T-follicular helper cells promote functional antibody production during Plasmodium falciparum infection

The most advanced malaria vaccine only has approximately 30% efficacy in target populations, and avenues to improve next generation vaccines need to be identified. Functional antibodies are key effectors of both vaccine induced and naturally acquired immunity, with induction driven by T-follicular helper cells (TfH) CD4+ T cells. We assessed circulating TfH (cTfH) responses and functional antibody production in human volunteers experimentally infected with Plasmodium falciparum. Longitudinal single-cell RNA-sequencing of cTfH revealed peak transcriptional activation and clonal expansion of major cTfH subsets occurred at day 8 following infection and a population structure of cTfH capturing phenotypical subsets of Th1- and Th2-like cells. Among 40 volunteers, infection resulted in the emergence of activated ICOS+ cTfH cells. During peak infection, activation was restricted to Th2-like cTfH cells, while Th1-like cTfH cell activation occurred one week after treatment. To link cTfH activation to antibody induction, we assessed the magnitude and function of anti-malarial IgM and IgG after infection. The functional breadth and magnitude of parasite-specific antibodies was positively associated with Th2-cTfH activation. In contrast, Th1-cTfH activation was associated with the induction of plasma cells, which we have previously shown have a detrimental role in germinal cell formation and antibody development. Thus, we identified that during P. falciparum malaria infection in humans, the activation of Th2-cTfH but not other subsets correlates with the development of functional antibodies required for protective immunity. Data for the first time identify a specific cellular response that can be targeted by future malaria vaccines to improve antibody induction.

immunology↗