Fig. 5

Mouse PD1-Fc-OX40L ARC is efficacious at treating CT26 colon cancer tumors and increasing survival. a Mice were inoculated subcutaneously on the rear flank with 5 × 10⁵ CT26 cells on day 0, and then treated with 2 doses (all by IP injection on days 5 & 7 once the tumors established and were ~ 4–6 mm in diameter), consisting of 100 μg for each antibody dose and either 100 μg, 150 μg or 300 μg for each dose of the murine PD1-Fc-OX40L ARC. Each line represents the tumor growth from an individual mouse. The first dotted line (~day 18) represents the mean when all untreated mice reached tumor burden. On day 30, surviving mice were challenged with a secondary tumor consisting of 3 × 10⁵ cells on the opposing rear flank. Thirteen new untreated mice were also inoculated on day 30 as a control for tumor re-challenge growth. All ARC treated mice that survived until the day 30 challenge, were combined when plotting the ‘re-challenge’ tumor growth curves. b Kaplan-Meier curves were generated for each treatment group, and are plotted identically in order to directly compare sample groups. c A cohort of mice was euthanized 13 days following tumor inoculation, and tumors were excised, dissociated, and subjected to immune phenotyping by flow cytometry. Total populations of CD4⁺ and CD8⁺ T cells were assessed, as well as CD4⁺CD25⁻ effector and CD8⁺AH1⁺ antigen-specific cytotoxic cells. d Some mice were treated on days − 1, 1 and 10 with CD4, CD8, or a combination of the two, depleting antibodies. CT26 tumors were again inoculated on day 0, and mice were treated with two IP treatments of 300 μg of the mPD1-Fc-OX40L ARC on days 5 and 7. The percent change in tumor growth between the first treatment day (day 5) and day 17 is shown