Biology subjects

Eyer, K.

Publications and source records attributed to Eyer, K..

3 recordsLinked to original sources

bioRxiv2022

Single cell profiling reveals functional heterogeneity and serial killing in human peripheral and ex vivo-generated CD34+ progenitor derived Natural Killer cells

Increasing evidence suggest that Natural killer (NK) cells are composed of distinct functional subsets. This multi-functional role displayed by NK cells have made them an attractive choice for anti-cancer immunotherapy. A functional NK cell repertoire is generated through cellular education, resulting in heterogeneous NK cell population with distinct capabilities to respond to different stimuli. The application of a high-throughput droplet-based microfluidic platform allows monitoring of NK cell-target cell interactions at single-cell level and in real-time. Through fluorescence-based screening of around 80,000 droplets, with different Effector:Target ratios, a fully automated image analysis allows for the assessment of individual killing events in each droplet over time. We observed a variable response of single NK cells towards different target cells and identified a distinct population of NK cells capable of inducing multiple target lysis, coined as serial killers. To meet the increasing clinical demand for NK cells several sources, such as umbilical cord blood (UCB), have successfully been explored. By assessing the cytotoxic dynamics, we showed that single UCB-derived CD34+ hematopoietic progenitor (HPC)-NK cells display superior anti-tumor cytotoxicity. Additionally, with an integrated analysis of cytotoxicity and cytokine secretion we showed that target cell interactions augmented cytotoxic as well as secretory behavior of NK cells. By providing an in-depth assessment over NK cell functions, this study provides crucial information on diversity and functional characteristics of peripheral blood NK cells and ex vivo-generated HPC-NK cells to develop and improve of NK cell-based cancer immunotherapy.

immunology↗

bioRxiv2021

Single-cell analyses of immune thrombocytopenic patients reveal multiorgan dissemination of high-affinity autoreactive plasma cells

The major therapeutic goal for immune thrombocytopenia (ITP) is to restore normal platelet counts using drugs to promote platelet production or by interfering with mechanisms responsible for platelet destruction. 80% of patients possess anti-integrin IIb{beta}3 (GPIIbIIIa) IgG autoantibodies causing platelet opsonization and phagocytosis. The spleen is considered the primary site of autoantibody production by autoreactive B cells and platelet destruction. The immediate failure in ~50% of patients to recover a normal platelet count after anti-CD20 Rituximab-mediated B cell depletion and splenectomy suggest that autoreactive, rituximab-resistant, IgG-secreting B cells (IgG-SC) reside in other anatomical compartments. We analyzed >3,300 single IgG-SC from spleen, bone marrow and/or blood of 27 patients with ITP revealing high inter-individual variability in affinity for GPIIbIIIa with variations over 3 logs. IgG-SC dissemination and range of affinities were however similar per patient. Longitudinal analysis of autoreactive IgG-SC upon treatment with anti-CD38 mAb daratumumab demonstrated variable outcomes, from complete remission to failure with persistence of high-affinity anti-GPIIbIIIa IgG-SC in the bone marrow. This study demonstrates the existence and dissemination of high-affinity autoreactive plasma cells in multiple anatomical compartments of patients with ITP that may cause the failure of current therapies.

immunology↗

bioRxiv2020

Quantitative modeling of the effect of antigen dosage on B-cell affinity distributions in maturating germinal centers

Affinity maturation is a complex dynamical process allowing the immune system to generate antibodies capable of recognizing antigens. We introduce a model for the evolution of the distribution of affinities across the antibody population in germinal centers. The model is amenable to detailed mathematical analysis, and gives insight on the mechanisms through which antigen availability controls the rate of maturation and the expansion of the antibody population. It is also capable, upon maximum-likelihood inference of the parameters, to reproduce accurately the distributions of affinities of IgG-secreting cells we measure in mice immunized against Tetanus Toxoid under largely varying conditions (antigen dosage, delay between injections). Both model and experiments show that the average population affinity depends non-monotonically on the antigen dosage. We show that combining quantitative modelling and statistical inference is a concrete way to investigate biological processes underlying affinity maturation (such as selection permissiveness), hardly accessible through measurements.

immunology↗