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Dendritic Cell Immunomodulator Screening Assay

The screening platform identifies compounds that modulate dendritic cell function, for drug discovery
in cancer immunotherapy, autoimmunity, allergies, infectious diseases & transplant rejection. This is
a high content flow cytometry platform with up to 12 independent fluorescent readouts.

Background

Dendritic cells (DCs) are the key antigen presenting cells responsible for initiating adaptive immune response to pathogens and tumour antigens. In vitro assays based on DCs can be used to study drug & vaccine candidates. Existing technologies, based on DCs matured from blood precursors, miss ~half of the DC’s phenotypic repertoire because matured DCs are committed to an activated state.

The Doolan Lab in JCU has developed a screening platform based on resting-state DCs, with the novel capability of detecting compounds which up-regulate or down-regulate DC-mediated antigen presentation and co-stimulation.

Test compounds are incubated with dendritic cells in 96 well plate format and assayed with high- throughput, multi-parameter flow cytometry. Up to 12 independent readouts provide a comprehensive profile of DC function including antigen presentation (MHC class I and II expression, peptide-MHC-I complexes), co-stimulation signalling (OX40L, CD80, CD86, CD70, CD40, CD44), checkpoint signalling (PD-L1, PD-L2), migratory potential (chemokine receptors CCR5 and CCR7) and phagocytosis (bead uptake). Specific readouts can be custom-tailored to individual screening applications.

Some examples of results are as follows:

  • Cholera toxin is a well known experimental vaccine adjuvant and induced strong up-regulation of expression of all DC activation markers, including co-stimulation signals, MHC molecules and cytokine receptors (Figure 1).
  • Curcumin, a known co-stimulation inhibitor, induced strong up-regulation of antigen-presenting molecule MHC-II combined with down-regulation of multiple co-stimulation signals, including OX40L, CD70, CD80, CD40 and CD44 (Figure 1).
  • Contrary to expectations, NPE1 from commercial suppliers induced strong down-regulation of all DC activation markers except for CD40 (Figure 1). Compounds with this activity profile may be useful for inducing broad suppression of immune responses
  • In addition to these prototypical hit compounds, other known immunomodulatory compounds have been tested and showed a variety of activity patterns. Examples include Resveratrol (Figure 1).

Graphs showing prototypical results showing different types of activity profiles of dendritic cells.

Fig. 1. Prototypical results showing different types of activity profiles of dendritic cells.

The assay has a better hit rate compared to other DC assays. Positive hits are expected to show immunomodulatory activity in vivo.

The assay is a screening tool for different types of therapeutics. A variety of DC activity profiles can be detected including the following:

  • Hit compounds with immunostimulant activity profile may have therapeutic potential as vaccine adjuvants or for cancer immunotherapy.
  • Compounds with co-stimulation inhibitor activity profile may be useful for treating auto-immune conditions.
  • Compounds with immunosuppressor activity profile may be useful for inducing broad suppression of immune responses within a narrow time window, such as during organ transplantation.

James Cook University is offering compound screening and hit validation on a fee for service basis, and is open to opportunities for collaborative research, co-development and out-licensing.

Seeking:

  • Licensing
  • Commercial partner
  • Development partner
  • Copyright
  • Know-how based
  • Patent application submitted
  • Prof Denise Doolan