Abstract Innate mononuclear phagocytic system (MPS) cells preserve mucosal immune homeostasis. Here, we investigated their role at nasal mucosa following challenge with house dust mite. We combined single cell proteome and transcriptome profiling on immune cells from nasal biopsy cells of allergic rhinitis and non-allergic subjects, before and after repeated nasal allergen challenge. Nasal biopsies of patients showed infiltrating inflammatory HLA-DR hi CD14 + monocytes and CD16 + monocytes, and transcriptional changes in resident CD1C + CD1A + conventional dendritic cells (cDC)2 following challenge. Importantly, although clinically silent, non-allergic individuals displayed a distinct innate MPS response to allergen challenge: predominant infiltration of myeloid-derived suppressor cells (HLA-DR low CD14 + monocytes), as well as cDC2 clusters expressing increased inhibitory/tolerogenic transcripts. Therefore, we identified not only clusters involved in airway inflammation but also a non-inflammatory, homeostatic blueprint of innate MPS responses to allergens in non-allergic individuals. Future therapies should target innate MPS for treatment of inflammatory airway diseases. Abstract Figure
Multi-parametric flow and mass cytometry allows exceptional high-resolution exploration of the cellular composition of the immune system. A large panel of computational tools have been developed to analyze the high-dimensional landscape of the data generated. Analysis frameworks such as FlowSOM or Cytosplore incorporate clustering and dimensionality reduction techniques and include algorithms allowing visualization of multi-parametric cytometric analysis. To additionally provide means to quantify specific cell clusters and correlations between samples, we developed an R-package, called cytofast, for further downstream analysis. Specifically, cytofast enables the visualization and quantification of cell clusters for an efficient discovery of cell populations associated with diseases or physiology. We used cytofast on mass and flow cytometry datasets based on the modulation of the immune system upon immunotherapy. With cytofast, we rapidly generated visual representations of group-related immune cell clusters and showed correlations with the immune system composition. We discovered macrophage subsets that significantly decrease upon cancer immunotherapy and distinct prime-boost effects of prophylactic vaccines on the myeloid compartment. Cytofast is a time-efficient tool for comprehensive cytometric analysis to reveal immune signatures and correlations. Cytofast is available at Bioconductor.
Vaccination of malaria-naive volunteers with a high dose of Plasmodium falciparum sporozoites chemoattenuated by chloroquine (CQ) (PfSPZ-CVac [CQ]) has previously demonstrated full protection against controlled human malaria infection (CHMI). However, lower doses of PfSPZ-CVac [CQ] resulted in incomplete protection. This provides the opportunity to understand the immune mechanisms needed for better vaccine-induced protection by comparing individuals who were protected with those not protected. Using mass cytometry, we characterized immune cell composition and responses of malaria-naive European volunteers who received either lower doses of PfSPZ-CVac [CQ], resulting in 50% protection irrespective of the dose, or a placebo vaccination, with everyone becoming infected following CHMI. Clusters of CD4+ and γδ T cells associated with protection were identified, consistent with their known role in malaria immunity. Additionally, EMRA CD8+ T cells and CD56+CD8+ T cell clusters were associated with protection. In a cohort from a malaria-endemic area in Gabon, these CD8+ T cell clusters were also associated with parasitemia control in individuals with lifelong exposure to malaria. Upon stimulation with P. falciparum-infected erythrocytes, CD4+, γδ, and EMRA CD8+ T cells produced IFN-γ and/or TNF, indicating their ability to mediate responses that eliminate malaria parasites.
Antibody glycosylation patterns can affect antibody functionality and thereby contribute to protection against invading pathogens. During pregnancy, maternal antibodies can be transferred through the placenta and contribute to modulating both the mother's and her child's immune responses. Although several studies of IgG glycosylation during pregnancy have been carried out, very few cohorts studied were from sub-Saharan Africa, where exposure to microorganisms and parasites is high. In Lambaréné, Gabon, 106 pregnant women in their third trimester were enrolled into this study. At enrolment, urine, stool, and blood samples were collected from the mothers to assess Schistosoma haematobium (S. haematobium), Plasmodium falciparum (P. falciparum) and other parasite infections. During delivery, cord blood samples were collected. The children were followed, and blood samples were collected at 9 and 12 months of age. IgG Fc glycosylation was measured by liquid chromatography-mass spectrometry, determining fucosylation, galactosylation, sialylation, bisection, and sialylation per galactose (SA/gal). Among the 106 pregnant women, 33 (31%) were infected by at least one parasite. The antibody glycosylation patterns in maternal and cord blood showed distinct profiles when compared to that of infants at 9 and 12 months. IgG galactosylation was higher in maternal/cord blood, while fucosylated IgG was higher in children up to 1 year of age. Maternal parasitic infection was associated with lower IgG2 and IgG3/IgG4 galactosylation in cord blood and lower IgG3/IgG4 galactosylation in children. When maternal IgG galactosylation and, consequently, cord blood were categorized as high, children at 9 and 12 months of age showed higher IgG galactosylation compared to children of mothers with low IgG galactosylation. As IgG Fc galactosylation can have functional consequences, it might provide valuable information for developing effective preventive and treatment strategies for vulnerable populations.
Abstract Schistosomiasis is a prevalent helminthiasis, affecting over 230 million people worldwide, with varied, stage specific morbidity. Whilst the Th2 and regulatory immune responses in chronic infection have been relatively well studied, we have little understanding of human immune responses during acute infection. This is despite the initial infective stages being proposed as crucial targets for much-needed vaccine development. Here, we comprehensively map immune responses in male and female single-sex controlled human Schistosoma mansoni infection. Using unbiased, high dimensional techniques we show that human immune responses to male and female single-sex infection are comparable. An early Th1-biased inflammatory response was observed at week 4 post infection, which was particularly apparent in individuals experiencing symptoms of acute schistosomiasis. This included expansion of HLA-DR + effector memory T cells, CD38 + monocytes and an increase in serum IFNγ. By week 8 post infection these inflammatory responses were followed by an expansion of Th2 and of regulatory cell subsets, including IL-10 producing CD4 - CD8 - T cells, CD11c + atypical memory B cells and serum IL-10. This study provides immunological insight into the clinical manifestations of acute schistosomiasis, as well as critical context through which to understand the development of immune responses observed in natural infection. One sentence summary Controlled human schistosome infection reveals cellular and cytokine responses to schistosome infection, with early inflammatory responses in symptomatic individuals at week 4 and a balanced Th1, Th2 and regulatory response in all participants by week 8.
Innate mononuclear phagocytic system (MPS) cells preserve mucosal immune homeostasis. We investigated their role at nasal mucosa following allergen challenge with house dust mite. We combined single-cell proteome and transcriptome profiling on nasal immune cells from nasal biopsies cells from 30 allergic rhinitis and 27 non-allergic subjects before and after repeated nasal allergen challenge. Biopsies of patients showed infiltrating inflammatory HLA-DRhi/CD14+ and CD16+ monocytes and proallergic transcriptional changes in resident CD1C+/CD1A+ conventional dendritic cells (cDC)2 following challenge. In contrast, non-allergic individuals displayed distinct innate MPS responses to allergen challenge: predominant infiltration of myeloid-derived suppressor cells (MDSC: HLA-DRlow/CD14+ monocytes) and cDC2 expressing inhibitory/tolerogenic transcripts. These divergent patterns were confirmed in ex vivo stimulated MPS nasal biopsy cells. Thus, we identified not only MPS cell clusters involved in airway allergic inflammation but also highlight novel roles for non-inflammatory innate MPS responses by MDSC to allergens in non-allergic individuals. Future therapies should address MDSC activity as treatment for inflammatory airway diseases.
