Journal: Journal for Immunotherapy of Cancer

Article Title: Oncolytic virotherapy potentiates chemo-PD-1 immunotherapy by engaging chemo-resistant bystander CD8+ T cells

doi: 10.1136/jitc-2026-014897

Figure Lengend Snippet: Profound antitumor effects by combined OV-BYTE, chemotherapy and PD-1 blockade. ( A ) Schematic of the experimental design for B . Naïve C57BL/6 mice were infected with LCMV Armstrong, followed by subcutaneous engraftment of MC38 tumor cells on day 30 post infection. From days 5 to 17 post tumor engraftment, mice were intraperitoneally administered cisplatin (2.5 mg/kg) and pemetrexed (300 mg/kg) on days 5, 8, 11, 14, and 17; concurrently, intratumoral injections of NDV-GP were performed from days 5 to 11 post engraftment. Meanwhile, mice were intraperitoneally administered αPD-L1 antibody treatment (PD-1 ICB) on days 18, 21 and 24. Control groups included those receiving NDV-GP alone, chemotherapy alone, αPD-L1 alone, the corresponding dual therapies, or no treatment, were included where indicated. ( B ) Tumor growth curves of MC38 tumor-bearing mice. ( C ) Schematic of the experimental design for D and E . Patient-derived CRC samples were processed to generate CRC organoids in vitro, which were then co-cultured with autologous PBMCs. Co-cultured cells were treated with medium (control), anti-PD-1 antibody, CT regimen comprising OXP and 5-FU, NDV-H1N1 NP plus NDV-RBD (NDV-NP/RBD), or combination groups (including NDV-NP/RBD+CT, CT + αPD-1, NDV-NP/RBD + αPD-1, and NDV-NP/RBD+CT + αPD-1). Treated co-cultures were analyzed via confocal imaging using Calcein-AM (viable cells, green) and PI (dead cells, red) staining, alongside quantitative response index assessment to evaluate treatment efficacy. ( D ) Representative confocal micrographs (brightfield and fluorescence) of patient-derived CRC organoids co-cultured with autologous PBMCs. Organoids were stained with Calcein-AM (green, viable cells) and PI (red, dead cells) across the treatment groups outlined in C . ( E ) The response index of CRC organoids, as calculated by the ratios of dead tumor cells (PI + ) relative to the total tumor cells (Calcein-AM + viable cells and PI + dead cells) across all groups in D . All data are representative of at least two independent experiments. Two-way ANOVA was used to compare tumor growth curves in ( B ). One-way ANOVA with Turkey’s test was used in ( E ). Center values and error bars in ( B and E ) indicate mean and SEM. *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001. ANOVA, analysis of variance; CRC, colorectal cancer; CT, chemotherapy; GP, glycoprotein; ICB, immune checkpoint blockade; i.t., intratumoral; LCMV, lymphocytic choriomeningitis virus; NDV, Newcastle disease virus; ns, not significant; OV-BYTE, oncolytic virus encoding T BYS cell epitopes; OXP, oxaliplatin; PBMC, peripheral blood mononuclear cell; PD-1, programmed cell death protein-1; PD-L1, programmed death-ligand 1; PI, propidium iodide; q.d., once daily (quaque die); RBD, receptor-binding domain; T BYS , bystander memory CD8 + T cell; 5-FU, 5-fluorouracil.

Article Snippet: For PD-1 ICB treatment, mice received intraperitoneal injections of 200 μg of anti-programmed death-ligand 1 (PD-L1) antibody (Bio X Cell, BE0101, RRID: AB_10949073).

Techniques: Infection, Control, Derivative Assay, In Vitro, Cell Culture, Imaging, Staining, Fluorescence, Virus, Binding Assay