Journal: bioRxiv
Article Title: Potent antitumor activity of a designed interleukin-21 mimic
doi: 10.1101/2024.12.06.626481
Figure Lengend Snippet: ( A ) Pre-activated human and murine CD8 + T cells were treated with increasing doses of native IL-21 and 21h10 for 20 minutes and stained with AF488-phospho-STAT1 and AF647-phospho-STAT3 for flow cytometry analysis. ( B ) Genes related to cellular signaling and phenotype are compared for expression levels between murine CD8 + T cells treated with PBS, mIL-21, or 21h10 at 100 pM or 1 nM. * indicates memory-related genes, and ** indicates effector-related genes. Murine CD8 + T cells were pre-activated with TCR signals and treated with the cytokines at different concentrations for 24 hours, and cells were harvested for RNA-sequencing. ( C ) The percentage of IFN-𝛾-secreting cells within isolated CD8 + T cells upon treating PBS, mIL-21, or 21h10 at 1 nM, was quantified using flow cytometry after 5 hours of stimulation with PMA/Ionomycin in the presence of a protein transport inhibitor. ( D ) LCMV was inoculated into healthy mice along with daily injections of PBS, mIL-21 (2.5 µg per mouse), or 21h10 (2.5 µg per mouse). LCMV-specific CD8 + T cells from PBMC and spleen were analyzed for granzyme B expression. ( E ) Computational model of 21AT36, which is redesigned from 21h10 using ProteinMPNN, to bind IL-21R but not bind 𝛾 c . The mutated residues are highlighted in red, which abolish interactions with 𝛾 c . The 𝛾 c is included in the figure to show where the interface is positioned, not to imply that 21AT36 binds to 𝛾 c . ( F ) Western blot for STAT and pSTAT with vehicle (PBS), mIL-21, 21h10, and 21AT36 in TRP1 high CD8 + T cells. ( G ) MC38-bearing mice were treated with PBS, 21AT36, 21h10, or anti-PD-1 for 14 days. ( H ) Mice were inoculated with MC38 and treated with PBS, mIL-21, 10-fold dose mIL-21, and 21h10. ( I ) Western blot for STAT and pSTAT in the spleens of mice treated with vehicle (PBS), mIL-21, and 21h10 ( J ) Normalized pSTAT3/STAT3 in spleens of treated mice over 24 hours from ( I ). ( K ) MC38 rechallenges with MC38-survivor mice from previous 21h10 or anti-PD-1 treatment.
Article Snippet: Two days before and on the day of tumor inoculations, mice were treated with anti-CD4 (150 µg per mouse; Bioxcell Cat# BE0003-1) and/or anti-CD8 depleting antibodies (150 µg per mouse; Bioxcell (valid) # BE0061) or rat IgG2b isotype (150 µg per mouse; clone LTF-2, BioXCell Cat# BE0090) diluted in sterile endotoxin-free PBS.
Techniques: Staining, Flow Cytometry, Expressing, RNA Sequencing Assay, Isolation, Western Blot