Carterra’s LSA enables a highly parallel interaction analysis to be performed on large antibody libraries, up to 384 binding interactions at once, accelerating the determination of binding kinetics, affinities and epitope specificities. This antibody discovery platform delivers a highly comparative analysis of clones, increasing confidence in the comparison and facilitating the benchmarking of libraries against one another by merging them into the same experiment. Of particular note, the Carterra LSA enables comprehensive epitope binning studies to be performed on up to 384 antibodies per experiment, allowing for a full 384 x 384 interaction analysis matrix in an unattended run, supported with sophisticated and intuitive data analysis software. The epitope binning picture gains depth, resolution, and nuance with the size of the antibody panel explored, allowing you to identify rare epitopes that lower-throughput assays would overlook. Assessing the quality of an antibody library in a functional way, in terms of its binding properties, is highly valuable to validating antibody discovery platforms.
Bispecific antibodies in cancer immunotherapy have found particular success via a so-called “T-cell redirecting” mechanism of action (MOA) in which one arm of the bispecific molecule targets a T-cell receptor, such as CD3, and the other targets a tumor-specific antigen, such as CD19 or EpCAM, thereby redirecting T-cell cytotoxicity to malignant cells, as employed in the two market-approved bispecific antibodies, Blinatumomab (Amgen) and Catumaxomab (Trion). Other MOAs that are actively pursued with bispecific antibodies are tumor-targeted immunomodulators, in the bispecific molecule targets a tumor-associated antigen and an immunomodulating receptor, such as CD40 or 4-1BB, and dual immunomodulators, in which the bispecific targets two distinct immunomodulators, such as PD-1 or PD-L1 combined with LAG-3 or TIM-3. The clinical success of bispecific antibodies clearly relies upon having a deep understanding of the MOA. There must a solid biological rationale for the bispecific, qualified target specificities, appropriate format and presence of absence of an Fc domain to engage Fc receptors, where relevant to the MOA.
The Carterra LSA enables interaction analysis to be performed on hundreds of binding interactions in parallel, accelerating the deep characterization of antibody libraries in terms of their binding kinetics, affinities, and epitope specificities. Knowledge of these key binding parameters is critical to understanding the MOA of an antibody and can help guide the selection of clones with the desired functional properties for a given therapeutic purpose.
ADCs have suffered from having a narrow therapeutic index because striking the right balance between potency and toxicity is challenging. From a functional perspective, it is important that the conjugation itself does not interfere with the antibody’s ability to bind its target antigen and Fc receptors. Fc engineering aimed at altering an ADC’s interaction with the neonatal receptor (FcRn) to optimize its serum persistence is being explored as a strategy for improving an ADC’s therapeutic index. A typical ADC campaign requires careful analytical characterization of a large panel of variants to empirically converge upon the most promising leads warranting further evaluation in terms of potency and toxicity in cell-based (in vitro) and animal-based (in vivo) tumor models.
The Carterra LSA enables the parallel analysis of up to 384 binding interactions, using surface plasmon resonance (SPR), the de facto method for measuring the binding kinetics and affinities of protein/protein interactions. High throughput SPR accelerates campaigns such as ADCs by providing key information about binding properties that guide the selection of molecules with the most therapeutic potential.
Designing a successful CAR and extending its scope to treating solid tumors requires deep understanding of its biological mechanism of action and fine tuning of its constituent parts to achieve the desired effect potently and safely. A CAR combines the target specificity of a monoclonal antibody with the signal-activating machinery and self-renewal capabilities of a T cell, thereby extending the application of engineered cellular therapy beyond that naturally restricted by major histocompatibility complex. A CAR has a modular architecture, comprising an extracellular domain (often an ScFv antibody fragment targeting a tumor-associated surface antigen, such as CD19, CD20 or BCMA), a flexible hinge, a transmembrane domain and an intracellular signaling domain (CD3 zeta) alone or in combination with co-stimulatory domains (such as CD3 zeta, CD28 or 4-1BB) to enhance the persistence and cytotoxicity of CAR-expressing cells. Optimizing CAR design is an empiric process requiring both in vitro and in vivo testing to converge upon a therapeutically viable product.
Choosing an antibody with an appropriate affinity and target specificity for use on a CAR is an important consideration that can influence its potency and selectively in killing tumors without causing collateral damage to healthy cells. The Carterra LSA is an SPR platform that can measure hundreds of antigen/antibody binding interactions in parallel, providing unprecedented throughput to accelerate the screening and characterization of critical antibody binding properties such as kinetics, affinity and epitope specificity that are assessed during the optimization of CAR components.