Abstract B103: Altering the mevalonate pathway to enhance CD8+ T-cell responses

Inhibitors of the mevalonate pathway have been found to induce inflammatory reactions and delay the progression of cancer. Emerging evidence suggests these inhibitors sensitise immune cells to signalling from the myeloid differentiation primary response gene 88 (MyD88) and in turn enhance NF-κB dependent activation of antigen presenting cells (APCs), an essential element in inducing an immune response. To further explore the adjuvant effect of these inhibitors, we designed a vaccine comprising an inhibitor of the mevalonate pathway conjugated to a tumor-specific peptide. We hypothesized that immunisation with these vaccines would elicit functional peptide-specific CD8+ T-cells. Using an in vivo mouse model, we found the vaccine generates greater peptide-specific cytotoxicity against targeT-cells bearing a human papillomavirus antigen than its unconjugated components, a chemical control vaccine or peptide alone. Moreover, the vaccine delayed outgrowth of an antigen-expressing tumor. Using human PBMCs, we obtained preliminary evidence that a similar vaccine can promote greater in vitro activation of CD8+ T-cells specific for a cytomegalovirus antigen than peptide alone. These results suggest that inhibitors of the mevalonate pathway can act as adjuvants in eliciting cytotoxic T-cell responses, and may have utility for the treatment or prevention of viral infections or neoplasia. Citation Format: Olivia K. Burn, Astrid Authier-Hall, Collin Brooks, Regan Anderson, Andrew Marshall, Gavin Painter, Robert Weinkove, Ian Hermans. Altering the mevalonate pathway to enhance CD8+ T-cell responses [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B103.