When selecting a compound to take forward in drug discovery, it is essential to evaluate the risk of immunogenicity and evaluate its functionality to move forward with the best leads into the preclinical stages. Christoph Schifflers, Immuno-oncology Team Lead at IQVIA, introduced the company which focuses on in vitro immunology from drug discovery all the way to the clinical phase.
In most cases, IQVIA works with PBMCs (peripheral blood mononuclear cells) from their biobank which can be used with fresh blood or cellular material derived from animals, including non-human primates. The readouts are classical, they involve flow cytometry and the analysis of cytokine production in the multiplex or single plex format.
Schifflers detailed various functional immune assays provided by the company, including mixed lymphocyte reactions, cytotoxicity assays, and peptide identification for therapeutic cancer vaccines. Schifflers explained that these assays can be customised in the context of modern immuno-oncology based on the specific mode of action of the compounds.
The mixed lymphocyte reaction can be simple but also complexified by including a selected cell population, such as regulatory T cells or M2-like macrophages. For developing cancer vaccines, Schifflers collaborates with ImmuneSpec, a Belgian company specialising in immunopeptidomics for Class 1 and Class 2 presented peptides.
The process begins with an immunogenicity assessment of a candidate peptide. The donors with PBMCs in the biobank are selected. Then, monocytes are isolated and differentiated into immature dendritic cells. The dendritic cells are loaded with the peptide of interest and undergo rounds of stimulation of T cells. Next, the team performs a FluoroSpot assay with intracellular cytokine staining to evaluate whether a specific peptide led to the enrichment of peptide reactive T cells or whether these T cells show a cytotoxic response. Schiffler presented a case study for a MART-1 short peptide that displayed this method in action.
Switching gears, Schifflers discussed the non-human primate assays, which are particularly relevant in pharmacology and toxicology studies. Due to high demand and ethical concerns, IQVIA developed in-house immunogenicity and functional assays using cyno materials. This contributes to the replacement, refinement, and reduction of non-human primate use in drug development.
The final section covered neutrophil assays. Neutrophils have a wide range of functions. They play a role not just in inflammation but also in autoimmunity and immuno-oncology, making them challenging assays. For the neutrophil activation assay, Schifflers performed live cell imaging-based analysis to monitor NET formation over time. The phagocytosis assay relies on fluorescently labelled target cells to track how neutrophils pick up membrane fragments. These assays can be used individually or in tandem to provide useful information on a compound's mode of action.
