A screening strategy to identify novel immunomodulators
Understanding the immunomodulatory activities of compounds is important to identify the unintended adverse immunomodulatory effects of therapeutic compounds in development and to select novel compounds that may provide benefit for those diagnosed with immunemediated disorders. In both these cases, it is desirable to identify compounds with immunomodulatory activity early in the drug discovery process in a medium-throughput format. A screening strategy has been designed to fulfil these needs. The first step in designing the strategy was to select informative assays and optimise individual assays to suit medium-throughput drug discovery. These individual assays investigated effects on a broad range of functions associated with innate and adaptive immune cells including macrophages (activation, cytokine production, phagocytosis and motility), helper T cells (activation and cytokine production), cytotoxic T cells (degranulation and cytokine production), and B cells (antibody production and cytokine production). Cost effectiveness and ease-of-use were important considerations during assay design and optimisation. Using a compound set comprised of positive controls (i.e. compounds known to alter specific immune functions), a data set was generated to guide the strategy design. Assays were ordered to efficiently use resources and reduce the generation of less informative data. Additionally, using data collected from this compound set, strategies to assess and identify immunomodulatory activity were built and analysed. A second set of compounds was used to validate the screening strategy, and this screen highlighted new and novel activities for these known compounds that suggests they possess additional immunomodulatory effects. Once validated, several novel compounds were run through the screen, including a traditional Samoan medicine, a heparan sulfate mimetic, and a novel anti-cancer agent; unique immunomodulatory activities were discovered. Finally, a hierarchical cluster analysis was used to cluster compounds sharing similar activity profiles and suggested the potential to develop further statistical methods to provide insight into compound characterisation. Together, this research has developed and validated a novel, medium throughput drug discovery system that can facilitate the identification of the immunomodulatory activities of compounds in the drug discovery environment.