Klaus Eyer

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Eyer

First Name

Klaus

ORCID

0000-0001-9344-5110

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Publications 1 - 10 of 60

Antibodies, repertoires and microdevices in antibody discovery and characterization
Schlotheuber, Luca Johannes; Lüchtefeld, Ines; Eyer, Klaus (2024)
Lab on a Chip
Therapeutic antibodies are paramount in treating a wide range of diseases, particularly in auto-immunity, inflammation and cancer, and novel antibody candidates recognizing a vast array of novel antigens are needed to expand the usefulness and applications of these powerful molecules. Microdevices play an essential role in this challenging endeavor at various stages since many general requirements of the overall process overlap nicely with the general advantages of microfluidics. Therefore, microfluidic devices are rapidly taking over various steps in the process of new candidate isolation, such as antibody characterization and discovery workflows. Such technologies can allow for vast improvements in timelines and incorporate conservative antibody stability and characterization assays, but most prominently screenings and functional characterization within integrated workflows due to high throughput and standardized workflows. First, we aim to provide an overview of the challenges of developing new therapeutic candidates, their repertoires and requirements. Afterward, this review focuses on the discovery of antibodies using microfluidic systems, technological aspects of micro devices and small-scale antibody protein characterization and selection, as well as their integration and implementation into antibody discovery workflows. We close with future developments in microfluidic detection and antibody isolation principles and the field in general.
High-resolution time-lapse imaging of droplet-cell dynamics via optimal transport and contrastive learning
Schlotheuber, Luca Johannes; Vollenweider, Michael; Gutjahr, Sven; et al. (2025)
Lab on a Chip
Single-cell analysis is essential for uncovering heterogeneous biological functions that arise from intricate cellular responses. Here, microfluidic droplet arrays enable high-throughput data collection through cell encapsulation in picoliter volumes, and the time-lapse imaging of these arrays further reveal functional dynamics and changes. However, accurate tracking of cell identities across time frames with large intervals in between remains challenging when droplets move significantly. Specifically, existing machine learning methods often depend on labeled data or require neighboring cells as reference; without them, these methods struggle to track droplets and cells across long distances within images with complex movement patterns. To address these limitations, we developed a pipeline that combines visual object detection, feature extraction via contrastive learning, and optimal transport-based object matching, minimizing the reliance on labeled training data. We validated our approach across various experimental and simulated conditions and were able to track thousands of water-in-oil microfluidic droplets over large distances and long intervals between frames (>30 min). We achieved high precision in previously untraceable scenarios, tracking 50 pl droplets in images with small, medium and large movements (corresponding to ∼126, ∼800 and ∼10 000 μm, respectively) with a success rate of correctly tracked droplets of >90% for average movements within 2-12 droplet diameters, and >60% for average movements of >100 droplet diameters. This workflow lays the foundation for the tracking of droplets over time in these arrays when large and complex movement patterns are present and where the uniqueness of the sample makes repeated experiments infeasible.
Deep phenotypic characterization of immunization-induced antibacterial IgG repertoires in mice using a single-antibody bioassay
Heo, Millie; Chenon, Guilhem; Castrillon, Carlos; et al. (2020)
Communications Biology
Antibodies with antibacterial activity need to bind to the bacterial surface with affinity, specificity, and sufficient density to induce efficient elimination. To characterize the anti-bacterial antibody repertoire, we developed an in-droplet bioassay with single-antibody resolution. The assay not only allowed us to identify whether the secreted antibodies recognized a bacterial surface antigen, but also to estimate the apparent dissociation constant (KD app) of the interaction and the density of the recognized epitope on the bacteria. Herein, we found substantial differences within the KD app/epitope density profiles in mice immunized with various species of heat-killed bacteria. The experiments further revealed a high cross-reactivity of the secreted IgG repertoires, binding to even unrelated bacteria with high affinity. This application confirmed the ability to quantify the anti-bacterial antibody repertoire and the utility of the developed bioassay to study the interplay between bacteria and the humoral response. © 2020, The Author(s).
A microfluidic vesicle screening platform
Kuhn Phillip; Eyer, Klaus; Allner, Steffen; et al. (2011)
Analytical Chemistry
Antibody density on bacteria regulates C1q recruitment by monoclonal IgG but not IgM
Aymerich, Nathan; Schlotheuber, Luca J.; Bucheli, Olivia T.M.; et al. (2024)
European Journal of Immunology
Antibodies that trigger the complement system play a pivotal role in the immune defense against pathogenic bacteria and offer potential therapeutic avenues for combating antibiotic-resistant bacterial infections, a rising global concern. To gain a deeper understanding of the key parameters regulating complement activation by monoclonal antibodies, we developed a novel bioassay for quantifying classical complement activation at the monoclonal antibody level, and employed this assay to characterize rare complement-activating antibacterial antibodies on the single-antibody level in postimmunization murine antibody repertoires. We characterized monoclonal antibodies from various antibody isotypes against specific pathogenic bacteria (Bordetella pertussis and Neisseria meningitidis) to broaden the scope of our findings. We demonstrated activation of the classical pathway by individual IgM- and IgG-secreting cells, that is, monoclonal IgM and IgG2a/2b/3 subclasses. Additionally, we could observe different epitope density requirements for efficient C1q binding depending on antibody isotype, which is in agreement with previously proposed molecular mechanisms. In short, we found that antibody density most crucially regulated C1q recruitment by monoclonal IgG isotypes, but not IgM isotypes. This study provides additional insights into important parameters for classical complement initiation by monoclonal antibodies, a knowledge that might inform antibody screening and vaccination efforts.
Baseline Single-Cell Differences in Polyfunctionality Between Systemic Autoinflammatory Diseases Patients and Healthy Controls
Linder, Aline; Diab, Farah; de Pontual, Loïc; et al. (2025)
European Journal of Immunology
Quantitative modeling of the effect of antigen dosage on B-cell affinity distributions in maturating germinal centers
Molari, Marco; Eyer, Klaus; Baudry, Jean; et al. (2020)
eLife
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 modeling and statistical inference is a concrete way to investigate biological processes underlying affinity maturation (such as selection permissiveness), hardly accessible through measurements.
Dynamic Activation of NADPH Oxidases in Immune Responses Modulates Differentiation, Function, and Lifespan of Plasma Cells
Bucheli, Olivia T.M.; Rodrigues, Daniela; Ulbricht, Carolin; et al. (2025)
European Journal of Immunology
NADPH-oxidase (NOX)-derived reactive oxygen species (ROS) have been described to play essential roles in B-cell activation processes. However, several key questions concerning NOX activity and subsequent ROS production remain unaddressed, including fundamental processes such as differentiation, functional competence, cellular metabolism, and viability. This study investigated these questions in a murine B-cell response after secondary immunization. We combined single-cell transcriptomics and single-cell detection of NOX activity and observed that various subsets of B cells dynamically express NOX1 and NOX2. The NOX+ cellular phenotype correlated with increased activity of metabolic pathways, augmented lactate production, lower IgG secretion rates, and markers for longevity. The NOX+ cellular phenotype was also associated with increased cellular stress and apoptosis, underscoring the intricate relationship between ROS and cellular survival. Consequently, these insights advance our understanding of how long-lived humoral immunity is formed.
A new mechanobiological era
Kurth, Felix; Eyer, Klaus; Franco-Obregón, Alfredo; et al. (2012)
Current Opinion in Chemical Biology
A facile protocol for the immobilisation of vesicles, virus particles, bacteria, and yeast cells
Kuhn, Philipp; Eyer, Klaus; Robinson, Tom; et al. (2012)
Integrative Biology

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Klaus Eyer

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