Polycations that absorb protons in response to the acidification of endosomes can theoretically disrupt these vesicles via the "proton sponge" effect. To exploit this mechanism, we created nanoparticles with a segregated core-shell structure for efficient, noncytotoxic intracellular drug delivery. Cross-linked polymer nanoparticles were synthesized with a pH-responsive core and hydrophilic charged shell designed to disrupt endosomes and mediate drug/cell binding, respectively. By sequestering the relatively hydrophobic pH-responsive core component within a more hydrophilic pH-insensitive shell, nontoxic delivery of small molecules and proteins to the cytosol was achieved in dendritic cells, a key cell type of interest in the context of vaccines and immunotherapy.

Immunostimulatory agonists such as anti-CD137 and interleukin-2 (IL-2) have elicited potent anti-tumor immune responses in preclinical studies, but their clinical use is limited by inflammatory toxicities that result upon systemic administration. We hypothesized that by rigorously restricting the biodistribution of immunotherapeutic agents to a locally accessible lesion and draining lymph node(s), effective local and systemic anti-tumor immunity could be achieved in the absence of systemic toxicity. We anchored anti-CD137 and an engineered IL-2Fc fusion protein to the surfaces of PEGylated liposomes, whose physical size permitted dissemination in the tumor parenchyma and tumor-draining lymph nodes but blocked entry into the systemic circulation following intratumoral injection. In the B16F10 melanoma model, intratumoral liposome-coupled anti-CD137 + IL-2Fc therapy cured a majority of established primary tumors, while avoiding the lethal inflammatory toxicities caused by equivalent intratumoral doses of soluble immunotherapy. Immuno-liposome therapy induced protective anti-tumor memory and elicited systemic anti-tumor immunity that significantly inhibited the growth of simultaneously-established distal tumors. Tumor inhibition was CD8+ T-cell-dependent and was associated with increased CD8+ T-cell infiltration in both treated and distal tumors, enhanced activation of tumor-antigen-specific T-cells in draining lymph nodes, and a reduction in regulatory T-cells in treated tumors. These data suggest that local nanoparticle-anchored delivery of immuno-agonists represents a promising strategy to improve the therapeutic window and clinical applicability of highly potent but otherwise intolerable regimens of cancer immunotherapy.

Immunostimulatory therapies that activate immune response pathways are of great interest for overcoming the immunosuppression present in advanced tumors. Agonistic anti-CD40 antibodies and CpG oligonucleotides have previously demonstrated potent, synergistic anti-tumor effects, but their clinical use even as monotherapies is hampered by dose-limiting inflammatory toxicity provoked upon systemic exposure. We hypothesized that by anchoring immuno-agonist compounds to lipid nanoparticles we could retain the bio-activity of therapeutics in the local tumor tissue and tumor-draining lymph node, but limit systemic exposure to these potent molecules. We prepared PEGylated liposomes bearing surface-conjugated anti-CD40 and CpG and assessed their therapeutic efficacy and systemic toxicity compared to soluble versions of the same immunoagonists, injected intratumorally in the B16F10 murine model of melanoma. Anti-CD40/CpGliposomes significantly inhibited tumor growth and induced a survival benefit similar to locally injected soluble anti-CD40+CpG. Biodistribution analyses following local delivery showed that the liposomal carriers successfully sequestered anti-CD40 and CpG in vivo, reducing leakage into systemic circulation while allowing draining to the tumor-proximal lymph node. Contrary to locally administered soluble immunotherapy, anti-CD40/CpG liposomes did not elicit significant increases in serum levels of ALT enzyme, systemic inflammatory cytokines, or overall weight loss, confirming that off-target inflammatory effects had been minimized. The development of a delivery strategy capable of inducing robust anti-tumor responses concurrent with minimal systemic side effects is crucial for the continued progress of potent immunotherapies toward widespread clinical translation.

Amphiphilic oligonucleotides synthesized by covalent conjugation between a hydrophobic diacyllipid tail and chemically stabilized RNA or DNA oligonucleotides can directly label tumor cells on injection into solid tumors. In a murine melanoma tumor model, cell membrane‐anchored CpG ODNs with a nuclease‐resistant phophorothioate backbone (row a) exhibited significantly enhanced immunostimulatory activity compared to soluble CpG (row b).

The transcription factor T-bet has been linked to increased susceptibility to systemic and organ-specific autoimmunity, but the mechanism by which T-bet expression promotes neuroinflammation remains unknown. In this study, we demonstrate a cardinal role for T-bet-dependent NKp46+ innate lymphoid cells (ILCs) in the initiation of CD4+ TH17-mediated neuroinflammation. Loss of T-bet specifically in NKp46+ ILCs profoundly impaired the ability of myelin-reactive TH17 cells to invade the central nervous system (CNS) tissue and protected the mice from autoimmunity. T-bet-dependent NKp46+ ILCs were localized in the meninges and acted as chief coordinators of meningeal inflammation by inducing the expression of pro-inflammatory cytokines, chemokines and matrix metalloproteinases, which in a concerted fashion facilitated T cell entry into CNS parenchyma. Our findings uncover a detrimental role of T-bet-dependent NKp46+ ILCs in the development of CNS autoimmune disease.

Amphiphile Oligonucleotide, die durch kovalente Konjugation zwischen einem hydrophoben Diacyllipid und chemisch stabilisierten RNA‐ oder DNA‐Oligonucleotiden synthetisiert wurden, markieren Tumorzellen nach Injektion in feste Tumoren. In einem murinen Melanom‐Modell zeigten zellmembranverankerte CpG‐ODNs mit nukleaseresistentem Phosphorthioat‐Rückgrat (Reihe a) deutlich höhere immunstimulatorische Aktivität als lösliche CpGs (Reihe b).

Very little is known about the transcription factor network that regulates the development of intestinal intraepithelial lymphocytes (IELs). In this issue of Immunity, Klose et al. (2014b) and Reis et al. (2014) demonstrate an essential role for T-bet in regulating the CD8αα IEL differentiation program.

Unlike conventional small‐molecule drugs, many of which can be formulated effectively with excipients to avoid degradation in the stomach and which exhibit reasonably efficient uptake through the gastrointestinal tract, biological drugs may exhibit lower stability and a greater sensitivity to enzymatic degradation, making oral delivery problematic. Thus, the majority of biologics are currently administered through subcutaneous/intramuscular injection or via intravenous infusion. Recent advances in delivery of traditional biologics include methods to increase the acceptable volume of drug solutions that can be administered subcutaneously.In addition, a number of alternative routes of administration for biologic drug products are being intensively investigated at the preclinical and clinical stages, such as intranasal, pulmonary, transcutaneous, and other routes, with some first examples of products recently licensed.This chapter will review current methods in use for marketed biologics and advanced approaches undergoing clinical testing.