Type 1 diabetes (T1D) is an autoimmune disease caused by the loss of self-tolerance toward insulin-producing pancreatic β-cells. Although the etiology of T1D is not fully understood, it is linked to dysregulation of the T-cell compartment. To identify T-cell signatures associated with T1D, we performed single-cell transcriptomic analysis of peripheral blood T-cells from newly diagnosed children, the same children after one year, and healthy donors. We observed reduced expression of genes related to effector and cytotoxic T-cell functions across conventional, unconventional, and regulatory T-cell subsets in diabetic children, particularly at the time of diagnosis. These findings were supported by flow cytometry analysis of the same cohort and by reanalysis of publicly available data. Overall, our results suggest that T1D is associated with impaired T-cell effector differentiation, which may contribute to immune dysregulation and loss of self-tolerance.

Radical control of malaria likely requires a vaccine that targets both the asymptomatic liver stages and the disease-causing blood stages of the human malaria parasite Plasmodium falciparum. While substantial progress has been made towards liver stage vaccines, the development of a blood stage vaccine is lagging behind. We have recently conducted a first-in-human clinical trial to evaluate the safety and immunogenicity of the recombinant, full-length merozoite surface protein 1 (MSP1FL) formulated with GLA-SE as adjuvant. Here, we show that the vaccine, termed SumayaVac-1, elicited both a humoral and cellular immune response as well as a recall T cell memory. The induced IgG and IgM antibodies were able to stimulate various Fc-mediated effector mechanisms associated with protection against malaria, including phagocytosis, release of reactive oxygen species, production of IFN-γ as well as complement activation and fixation. The multifunctional activity of the humoral immune response remained for at least 6 months after vaccination and was comparable to that of naturally acquired anti-MSP1 antibodies from semi-immune adults from Kenya. We further present evidence of SumayaVac-1 eliciting a recallable cellular cytotoxicity by IFN-γ producing CD8+ T cells. Our study revitalizes MSP1FL as a relevant blood stage vaccine candidate and warrants further evaluation of SumayaVac-1 in a phase II efficacy trial.
© 2023. Springer Nature Limited.

Absolute cell counts are typically measured in fresh samples, but this is impractical in large field studies. We compared quantification of leukocyte proportions and absolute counts using reference real-time methods (stain and lyse/no-wash (LNW) or hematology analyser) with a novel assay that allows long-term cryopreservation of fixed leukocytes for later counting (DLC-ICE: differential leukocyte count and immunophenotype in cryopreserved ex vivo whole blood). For the LNW method, whole blood (WB) was stained with fluorescent antibodies, then erythrocytes were lysed, and leukocytes fixed prior to flow cytometry. Alternatively, our novel DLC-ICE method entailed erythrocyte lysis and leukocyte fixation, cryopreservation and later staining of permeabilized cells prior to flow cytometry. Outcomes were proportions and absolute counts of granulocytes, lymphocytes, monocytes, T cells, B cells, and activated T cells within the leukocyte population. We also compared leukocyte subset counts in fresh WB from 51 healthy infants measured by hematology analyser at a rural clinical site or by DLC-ICE method after 2 years of cryopreservation. We observed excellent agreement and strong correlations between absolute counts or cell proportions measured by the LNW and DLC-ICE methods on fresh WB from 10 healthy adults. Compared to LNW, DLC-ICE yielded similar or brighter staining even after cryopreservation. Duration of cryopreservation, assessed monthly for 1 year, had little effect on cell enumeration: median coefficients of variation were below 15% for all outcomes. Under field site conditions, we observed strong correlations between infant leukocyte numbers measured in fresh samples by hematology analyser and those measured by DLC-ICE up to 2 years of cryopreservation. Our novel DLC-ICE method allows accurate flow cytometric quantification of cell subsets from fixed WB even after long-term cryopreservation. This method is ideal for batched, retrospective analysis of samples from large field studies, or when advanced flow cytometry equipment is not available for clinical research purposes. © 2014 International Society for Advancement of Cytometry.
© 2014 International Society for Advancement of Cytometry.