A Competition-Based Strategy for the Isolation of an Anti-Idiotypic Blocking Module and Fine-Tuning for Conditional Activation of a Therapeutic Antibody.

The masking of therapeutic antibodies by the installation of a blocking module that can be removed under certain physiological conditions, is becoming increasingly important to improve their safety and toxicity profile. To gain access to such masking units, we used chicken immunization in combination with yeast surface display and a competition-based FACS screening campaign to obtain anti-idiotypic single-chain Fv (scFv) fragments. This approach promotes the identification of functional masking units, since specificity and high affinity do not necessarily guarantee a paratope blocking effect.

T cell receptor-directed antibody-drug conjugates for the treatment of T cell-derived cancers.

T cell-derived cancers are hallmarked by heterogeneity, aggressiveness, and poor clinical outcomes. Available targeted therapies are severely limited due to a lack of target antigens that allow discrimination of malignant from healthy T cells. Here, we report a novel approach for the treatment of T cell diseases based on targeting the clonally rearranged T cell receptor displayed by the cancerous T cell population.

A Conditionally Activated Cytosol-Penetrating Antibody for TME-Dependent Intracellular Cargo Delivery.

Currently, therapeutic and diagnostic applications of antibodies are primarily limited to cell surface-exposed and extracellular proteins. However, research has been conducted on cell-penetrating peptides (CPP), as well as cytosol-penetrating antibodies, to overcome these limitations. In this context, a heparin sulfate proteoglycan (HSPG)-binding antibody was serendipitously discovered, which eventually localizes to the cytosol of target cells.

Conditional activation of an anti-IgM antibody-drug conjugate for precise B cell lymphoma targeting.

Cancerous B cells are almost indistinguishable from their non-malignant counterparts regarding their surface antigen expression. Accordingly, the challenge to be faced consists in elimination of the malignant B cell population while maintaining a functional adaptive immune system. Here, we present an IgM-specific antibody-drug conjugate masked by fusion of the epitope-bearing IgM constant domain.

Sactipeptide Engineering by Probing the Substrate Tolerance of a Thioether-Bond-Forming Sactisynthase.

Sactipeptides are ribosomally synthesized peptides containing a unique sulfur to α-carbon crosslink. Catalyzed by sactisynthases, this thioether pattern endows sactipeptides with enhanced structural, thermal, and proteolytic stability, which makes them attractive scaffolds for the development of novel biotherapeutics. Herein, we report the in-depth study on the substrate tolerance of the sactisynthase AlbA to catalyze the formation of thioether bridges in sactipeptides.

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Due to the large evolutionary distance between birds (Aves) und humans, immunization of chickens with human proteins results in a strong response of the bird's adaptive immune system to proteins of mammalian origin. Additionally, chicken-derived antibodies display less undesired cross-reactivity in analytical setups than conventional rodent-derived antibodies. Due to these features as well as the facile amplification of antibody-coding genes, chicken-derived antibodies emerged as promising molecules for the immunotherapy and various biotechnological applications.

Toward Fabrication of Bioactive Papers: Covalent Immobilization of Peptides and Proteins.

Herein, we report a novel two-step method for the covalent, site-directed, and efficient immobilization of proteins on lab-made paper sheets. First, paper fibers were modified with a peptidic anchor comprising enzyme recognition motifs. Four different conjugation strategies for peptide immobilization were evaluated with respect to reproducibility and fiber loading efficiency.

Simplifying the Detection of Surface Presentation Levels in Yeast Surface Display by Intracellular tGFP Expression.

Yeast surface display (YSD) is an ultra-high throughput method used in protein engineering. Protein-protein interactions as well as surface presentation on the yeast cell surface are verified through fluorophore-conjugated labeling agents.In this chapter we describe an improved setup for full-length surface presentation detection.