Unbiased Profiling of the Immunomodulatory Properties of Soluble Proteins

The function of the innate and adaptive immune system is tightly controlled by soluble signals such as cytokines on the one hand and cell-cell interactions on the other. Immunotherapeutics modulate these signaling axes to direct the human immune system against malignant cells and are promising to revolutionize the way how we treat cancer. Yet, not all malignancies respond equally well to existing immunotherapy and new targets are required.

Here we use a novel high content imaging method compatible with human PBMCs (Vladimer, Snijder et al., Nat. Chem. Biol. 2017) to systematically quantify the physical interaction patterns between CD3, CD4, CD8, CD11c, CD14, CD19 and CD56 positive cells in response to perturbation with 90 cytokines and soluble cell-surface receptors ex vivo . Whilst there are many tools to measure cytokines and other soluble immunoregulatory factors in high throughput (e.g., alpha screen), and potentially in a multiplexed fashion (e.g., cytokine bead arrays), the systematic measurement of cell-cell interactions in high-throughput has so far been elusive.

We were able to identify specific changes in cell-cell interaction patterns that could be reproduced over different donors in response to treatment with a protein or small molecule perturbations. We hypothesise that so far unknown immunomodulatory functions can be inferred by comparison of cell-cell interaction patterns in response to one treatment to the cell-cell interaction changes induced by molecules with known immunomodulatory properties. Further, we hypothesise that coregulation analysis between cell-cell interaction pairs can map out cell contact dependent regulatory circuits in an unbiased manner.

Overall, our method promises to become a valuable tool for the study of the immune system and phenotypic discovery of molecules with desired immunomodulatory properties. An overview of the method and preliminary results will be presented.