Doctor of Philosophy

dissertationPhosphate-metal complex formation is a naturally occurring toughening mechanism in underwater materials and has been incorporated into the synthetic hydrogel material discussed in this dissertation. Polyphosphate hydrogels were loaded with Ca2+ which crosslinks OPO3 groups in the hydrogel which increase the initial modulus from 0.04 to 10.3 MPa and rupture at a critical force to dissipate strain energy and act as a sacrificial network to preserve the integrity of the hydrogel. Phosphate metal crosslinks are electrostatic domains that are easily recoverable, which adds to the durability and usefulness of the hydrogels. This toughening mechanism was borrowed from the underwater caddisfly larvae, which spin a tough, adhesive silk fiber to manufacture protective mobile cases from sticks, rocks and other advantageously gathered materials. The caddisfly silk also uses serial domains of phosphates crosslinked with Ca2+ to increase modulus and produce strain induced yield, energy dissipation, and recoverability. In addition to metal ions, positively charged aminoglycoside antibiotics such as tobramycin can also be used as crosslinking agents. Due to electrostatically delayed diffusion, tobramycin is gradually released and exchanged with metal ions in biologically relevant Ca2+ and Mg2+ containing solutions. In the polyphosphate hydrogel system, tobramycin was included with and without the presence of Ca2+ to form a hydrogel with the capability to sustain tobramycin release for up to 70 days and totally eradicate pseudomonas aeruginosa biofilms within 48 hours. In the case of hydrogels loaded with Ca2+ and tobramycin, the hydrogels retained their toughness, and durability and thus may be used as structural materials in total joint replacement to reduce incidence of infection. Complex coacervation is an alternative to the polyphosphate-tobramycin hydrogel system and occurs as a phase separation where a dense coacervate of polyphosphate and tobramycin is formed. The formation of clear, fluid coacervate phase is dependent on salt concentration and is maximized at ~1M NaCl. Polyphosphate-tobramycin coacervates have a sustained release assay for up to 60 days. Additionally, the coacervate can be resuspended into micro droplets by vortex and subsequently aerosolized for pulmonary delivery of tobramycin. Aerosolized coacervate is ideal for treating chronic pulmonary infection in cystic fibrosis. It could not only improve rates of pseudomonas aeruginosa infection but also reduce the number of required doses and thus improve patient compliance

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

WTO must ban harmful fisheries subsidies

Sustainably managed wild fisheries support food and nutritional security, livelihoods, and cultures (1). Harmful fisheries subsidies—government payments that incentivize overcapacity and lead to overfishing—undermine these benefits yet are increasing globally (2). World Trade Organization (WTO) members have a unique opportunity at their ministerial meeting in November to reach an agreement that eliminates harmful subsidies (3). We—a group of scientists spanning 46 countries and 6 continents—urge the WTO to make this commitment..