IFN-α2, IFN-γ and IL-2 augment anti-tumor efficacy but do not increase tumor-accumulation of transferred cells.

<p>Mice bearing syngeneic B16.OVA tumors were adoptively transferred with 2x10⁶ CD8a⁺ enriched, polyclonally activated OT-I lymphocytes intraperitoneally and tumors were either left non-injected or injected with PBS or recombinant cytokine in PBS (n = 10). (a) Tumor growth was monitored every 2–3 days with an electronic caliper. Due to variation in tumor sizes at the beginning of the experiment, the results are represented as relative change compared to day 0 volume, which was set at 100%. (b-c) Levels of OT-I cells in tumors were quantified on days 4 (b) and 14 (c) post-transfer by pentamer staining and flow cytometry. (d) Proportion of major histocompatibility complex (MHC) class I molecules presenting OVA-derived peptide SIINFEKL and (e) mean fluorescence intensity (MFI) of mouse MHC class I H-2kb from tumor samples was assessed by flow cytometry on day 14 post-transfer (n = 5). Data presented as mean ± SEM. *P≤ 0.05, **P≤ 0.01, ***P≤ 0.001, ****P≤ 0.0001 by repeated measures ANOVA (a) or one-way ANOVA followed by Tukey’s post-hoc test (b-e).