Fig. 5: Checkpoint blockage benefits from ProIFN-optimized tumor microenvironment.
a–e C57BL/6 J mice were s.c. inoculated with 5 × 105 B16-OVA tumor cells and i.p. treated with 1 nmol of hIg, or mProIFNa4-Fc, on day 9, 12, and 15 (n = 5 animals for hIg, n = 4 animals for mProIFNa4-Fc). 5 days after the last treatment, mice were euthanized. Tumors and draining lymph nodes (dLNs) were extracted, digested in collagenase/DNase, and resuspended as single cells. Tumor-infiltrating T cells were analyzed via flow cytometry for the frequency of total CD45+ cells (a), CD8+ T cells (b), Foxp3+ T cells (c), CD8+/Foxp3+ ratio (d), and Ki67+CD8+ T cells (e). f–i C57BL/6 J mice were s.c. inoculated with 5 × 105 B16 cells and i.p. treated with 1 nmol of hIg or mProIFNa4-Fc on day 11 (n = 7 animals). Tumor tissues were harvested 48 h after treatment. Intracellular RNA was extracted for RT-qPCR assay to determine expression levels of CXCL-9 (f), CXCL-10 (g), CCL-17 (h), and CCL-22 (i). j, k PD-L1 expression in tumors and draining lymph nodes (dLNs) from tumor-bearing mice in a was measured by flow cytometry. Mean fluorescent intensities (MFIs) of PD-L1 staining in dLN (j) and tumor (k) were shown (n = 5 animals). l Combination of mProIFNa4-Fc and a-PD-L1 antibody therapy. C57BL/6 J mice were s.c. inoculated with 1 × 106 MC38 tumor cells and i.p. treated with 1 nmol of mProIFNa4-Fc on day 12, 14, and 16 (n = 8 animals). 200 μg anti-PD-L1 was i.p. administrated on day 12, and 16. Tumor growth was shown. Data are reported as mean ± s.e.m. Two-tailed t-tests (a–k) or two-way ANOVA (l) were performed to calculate p-values. Source data are provided as a Source data file.
