Fig. 2: Oral RC402 interacts with the host immune system in Peyer’s patch and triggers robust T cell immunity within the tumor microenvironment.

CT26 tumor-bearing mice were orally administered with AF647-fluorescent labeled RC402 and the reovirus distribution was serially monitored. A Schematic diagram depicting the gastrointestinal (GI) migration and distribution of orally administered RC402. B, C Representative images and quantifications of the fluorescent labeled RC402 localization in each organ over time (n = 3 per group). D Representative images showing reovirus and CD45⁺ leukocytes within terminal ileum and Peyer’s patch (PP). Arrows indicate RC402 infected mucosal epithelial cells. E Representative images showing the absence of RC402 within mesenteric lymph nodes (LN), spleen, and tumor tissues. F Comparison of reovirus transcripts within PP, LN, spleen, and tumor tissue after oral RC402 treatment (n = 4 per group). G Volcano plot showing transcriptome changes in reovirus-treated PP, LN, and tumor tissues compared with PBS-treated matched-control tissues after 7 days of oral RC402 treatment (n = 3 per group). Colored dots indicate significantly upregulated genes after oral RC402 treatment (one-tailed Student’s t test). Red lines denote P = 0.05. H Enrichment of Gene Ontology (GO) biological processes in each tissue after 7 days of oral RC402 treatment (n = 3 per group, one-tailed Fisher’s Exact test). I Heatmap showing the expression of genes related to innate immunity, interferons (IFNs), Th1/Th2 responses, T cell activation, immune checkpoints, and tumor microenvironment after 7 days of RC402 treatment (n = 3 per group). Values are fold changes in RC402-treated tissues compared with matched-control tissues. Data are pooled from two independent experiments. Values are expressed as the mean ± SD. Scale bars, 100 μm. Source data are provided as a Source Data file.