31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Pilot Scale Production of Mixed Alcohols from Wood

An integrated thermochemical biomass to ethanol process was demonstrated at the pilot scale at the National Renewable Energy Laboratory (NREL). A total of 233 h of pilot scale mixed alcohol production was achieved, comprising 81 h of continuous operation in methanol-derived syngas followed by 152 h of continuous operation in biomass-derived syngas. During this period the system generated 20 L of mixed alcohol product. The fully integrated biomass to mixed alcohol process was comprised of a solids feeder, fluidized bed indirect steam gasifier, thermal cracker, char collector, fluidized bed steam reformer, packed bed polishing steam reformer, scrubber, pressure-swing CO₂ adsorber, and gas-phase continuously stirred tank gas-to-liquid reactor (CSTR). Additional pumps, compressors, and blowers were used to convey gases, solids, and liquids. Tars and methane were reformed using sequential steps: first in a fluidized bed using an NREL-developed Ni-based catalyst followed by a fixed bed reactor loaded with pelletized, precious metal catalyst developed by Johnson Matthey. Mixed alcohols (a mixture of methanol, ethanol, 1-propanol, etc.) were produced using a metal sulfide catalyst developed at NREL. Under steady state conditions, the steam reformers converted >99.9, 97.0, and 86% of tars, benzene, and methane, respectively, in the producer gas. A simulated partial recycle of carbon dioxide to the gasifier was used to reduce the H₂:CO ratio of the reformed syngas to 3:1 without adding water gas shift reactors to the process or coking the reforming catalysts. When operating on biomass-derived syngas in a CSTR, the fuel synthesis catalyst produced as much as 31 g of EtOH·kg of catalyst^–1·h^–1 at a CO₂-free ethanol selectivity of 27% at 2000 psi, 300 °C, and 27% CO conversion. A bench scale packed bed reactor operated under analogous conditions produced 39 g of EtOH·kg of catalyst^–1·h^–1 at a CO₂-free ethanol selectivity of 28% showing reasonable parity between bench scale and pilot scale