Local delivery of cell surface-targeted immunocytokines programs systemic antitumor immunity.

Systemically administered cytokines are potent immunotherapeutics but can cause severe dose-limiting toxicities. To overcome this challenge, cytokines have been engineered for intratumoral retention after local delivery. However, despite inducing regression of treated lesions, tumor-localized cytokines often elicit only modest responses at distal untreated tumors. In the present study, we report a localized cytokine therapy that safely elicits systemic antitumor immunity by targeting the ubiquitous leukocyte receptor CD45. CD45-targeted immunocytokines have lower internalization rates relative to wild-type counterparts, leading to sustained downstream cis and trans signaling between lymphocytes. A single intratumoral dose of αCD45-interleukin (IL)-12 followed by a single dose of αCD45-IL-15 eradicated treated tumors and untreated distal lesions in multiple syngeneic mouse tumor models without toxicity. Mechanistically, CD45-targeted cytokines reprogrammed tumor-specific CD8+ T cells in the tumor-draining lymph nodes to have an antiviral transcriptional signature. CD45 anchoring represents a broad platform for protein retention by host immune cells for use in immunotherapy.

Surfactant-Mediated Assembly of Precision-Size Liposomes.

Liposomes can greatly improve the pharmacokinetics of therapeutic agents due to their ability to encapsulate drugs and accumulate in target tissues. Considerable effort has been focused on methods to synthesize these nanocarriers in the past decades. However, most methods fail to controllably generate lipid vesicles at specific sizes and with low polydispersity, especially via scalable approaches suitable for clinical product manufacturing. Here, we report a surfactant-assisted liposome assembly method enabling the precise production of monodisperse liposomes with diameters ranging from 50 nm to 1 µm. To overcome scalability limitations, we used tangential flow filtration, a scalable size-based separation technique, to readily concentrate and purify the liposomal samples from more than 99.9% of detergent. Further, we propose two modes of liposome self-assembly following detergent dilution to explain the wide range of liposome size control, one in which phase separation into lipid-rich and detergent-rich phases drives the formation of large bilayer liposomes and a second where the rate of detergent monomer partitioning into solution controls bilayer leaflet imbalances that promote fusion into larger vesicles. We demonstrate the utility of controlled size assembly of liposomes by evaluating nanoparticle uptake in macrophages, where we observe a clear linear relationship between vesicle size and total nanoparticle uptake.

Local delivery of cell surface-targeted immunocytokines programs systemic anti-tumor immunity.

Cytokine therapies are potent immunotherapy agents but exhibit severe dose-limiting toxicities. One strategy to overcome this involves engineering cytokines for intratumoral retention following local delivery. Here, we develop a localized cytokine therapy that elicits profound anti-tumor immunity by engineered targeting to the ubiquitous leukocyte receptor CD45. We designed CD45-targeted immunocytokines (αCD45-Cyt) that, upon injection, decorated the surface of leukocytes in the tumor and tumor-draining lymph node (TDLN) without systemic exposure. αCD45-Cyt therapy eradicated both directly treated tumors and untreated distal lesions in multiple syngeneic mouse tumor models. Mechanistically, αCD45-Cyt triggered prolonged pSTAT signaling and reprogrammed tumor-specific CD8+ T cells in the TDLN to exhibit an anti-viral transcriptional signature. CD45 anchoring represents a broad platform for protein retention by host immune cells for use in immunotherapy.