Fig 2: Pathway induction following IL-17 exposure.A. Overlapping and unique upregulated canonical pathway enrichment in bulk CD4+CD25- T-cells in IL-17A, IL-17F, and IL-17AF conditions compared to media-only cells. B. Bar chart of significantly (p < 0.05) altered in at least two of three conditions. C. Z-score of significantly enriched canonical pathways with non-unique pathways colored in grey. Top increased unique pathways labeled.

Fig 3: IL-17 cytokines affect naïve and bulk CD4+ T-cells but show no effect on memory T-cells.A. Schematic summary of the ex vivo treatment of bead-sorted bulk or memory CD4+ CD25- T-cells activated in media alone (control/baseline), IL-17A, IL-17F, or IL-17AF heterodimer. After activation, RNA was isolated and underwent mRNA sequencing. B. The number of significant genes upregulated and downregulated with IL-17A (yellow), IL-17F (orange) and IL-17AF (blue) within the indicated populations. Significance was defined as q-value < 0.05 and log2-fold change > 1 or < -1. C. Negatively selected CD4+25- T-cells were further sorted using either CD45RO or CD45RA magnetic beads resulting in bulk, naïve and memory T-cell populations, which were αCD3/αCD28-activated for 7 days in media alone (control) or in the presence of IL-17AF and then used as responder cells in flow cytometric suppression assays with autologous CD8+ T-cells as suppressors. ** p<0.005, *** p<0.001, n.s. = not significant by Paired Student T-test.

Fig 4: Memory T-cell non-responsiveness to IL-17 is not affected by local auto/paracrine action of naïve T-cell cytokines.Transwell cultures were set up in 24-well plates with transwell membrane inserts separating autologous presorted Memory and Naïve CD4+ T cells together (A) or individually (B and C), with indicated cytokine conditions (media alone, IL-17A, IL-17F, IL-17AF and IL-17A+IL-17F, panels D-H, respectively) stimulated with anti-CD3/anti-CD28-coated beads in culture for 7 days. On day 7, the cells were harvested, washed, stained with CFSE and subjected to CD8-mediated T-cell suppression assays with fixed anti-CD3 and anti-CD28 stimulation. Mean suppression +/- SEM for the 5 conditions is shown; n = 5 each; *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001.

Fig 5: Phase 1c PK profile of DC-806 through 28 days after the first dose.Graph detailing the group mean ± SD DC-806 plasma concentration by 200 mg BID (green circle) and 800 mg BID (blue diamond) groups on a semilogarithmic scale through Study Day 29. PK in psoriasis patients was comparable to healthy volunteer PK, with consistent trough levels over 28 days after achieving steady state around Day 3. The dotted line represents IC50 for recombinant human IL-17AA, as obtained using HEK-blue IL-17 cell-based assay (S1 Table). PK Concentration Analysis Set. Abbreviations: BID, twice daily; HEK: human embryonic kidney; IC50, half-maximal inhibitory concentration; IL-17, interleukin-17; PK, pharmacokinetic; SD, standard deviation.