Questo recentissimo studio pubblicato sul PNAS (Proceedings of the National Academy of Sciences), rivela che la temperatura ambiente all’interno dei laboratori causerebbe stress nei modelli murini utilizzati nella ricerca sul cancro umano, sopprimendone le risposte immunitarie ed influenzando di conseguenza i risultati dei test sperimentali che ”spesso costituiscono la base per lo sviluppo dei farmaci anticancro”.
[Kathleen M. Kokolus, Maegan L. Capitano, Chen-Ting Lee, Jason W.-L. Eng, Jeremy D. Waight, Bonnie L. Hylander, Sandra Sexton, Chi-Chen Hong, Christopher J. Gordon, Scott I. Abrams, and Elizabeth A. Repasky. Baseline tumor growth and immune control in laboratory mice are significantly influenced by subthermoneutral housing temperature. Published online before print November 18, 2013, doi:10.1073/pnas.1304291110 PNAS November 18, 2013]
We show here that fundamental aspects of antitumor immunity in mice are significantly influenced by ambient housing temperature. Standard housing temperature for laboratory mice in research facilities is mandated to be between 20–26 °C; however, these subthermoneutral temperatures cause mild chronic cold stress, activating thermogenesis to maintain normal body temperature. When stress is alleviated by housing at thermoneutral ambient temperature (30–31 °C), we observe a striking reduction in tumor formation, growth rate and metastasis. This improved control of tumor growth is dependent upon the adaptive immune system. We observe significantly increased numbers of antigen-specific CD8+ T lymphocytes and CD8+ T cells with an activated phenotype in the tumor microenvironment at thermoneutrality. At the same time there is a significant reduction in numbers of immunosuppressive MDSCs and regulatory T lymphocytes. Notably, in temperature preference studies, tumor-bearing mice select a higher ambient temperature than non-tumor-bearing mice, suggesting that tumor-bearing mice experience a greater degree of cold-stress. Overall, our data raise the hypothesis that suppression of antitumor immunity is an outcome of cold stress-induced thermogenesis. Therefore, the common approach of studying immunity against tumors in mice housed only at standard room temperature may be limiting our understanding of the full potential of the antitumor immune response.