Cell surface-targeted immunocytokines program systemic anti-tumor immunity
Systemically-administered cytokines are potent immunotherapy agents but exhibit severe dose-limiting toxicities. To overcome this challenge, cytokines have been engineered for intratumoral retention following local delivery. However, despite inducing regression of treated lesions, tumor-localized cytokines often elicit only modest abscopal effects at distal untreated tumors. Here we report a localized cytokine therapy that safely elicits potent systemic anti-tumor immunity by engineered targeting of the ubiquitous leukocyte receptor CD45. CD45-targeted immunocytokines (aCD45-Cyt) exhibit significantly diminished internalization rates relative to their wild-type counterparts; this prolonged surface retention sustains downstream pSTAT induction and enables both cis and trans signaling between lymphocytes. Intratumoral aCD45-Cyt administration led to decoration of leukocytes in the tumor and tumor-draining lymph node (TDLN) without systemic exposure. Therapeutically, a single dose of aCD45-IL12 followed by a single dose of aCD45-IL15 eradicated both treated tumors and untreated distal lesions in multiple syngeneic mouse tumor models. Mechanistically, prolonged exposure to aCD45-Cyt in the tumor and TDLN reprogrammed CD8+ T cells in the TDLN to exhibit an anti-viral transcriptional signature and expanded tumor-specific effector T cells in both the tumor and TDLN. CD45 anchoring represents a broad platform for protein retention by host immune cells for use in immunotherapy. Overall design: To understand how localized aCD45-Cyt treatment elicited such potent systemic immunity against B16F10 tumor, we performed gene expression profiling analysis on live CD3+CD8+CD44+p15E+ cells using data obtained from RNA-seq of 3 experimental groups and 5 mice from each experimental group, with a total number of 15 mice. Mice from the control group were injected with PBS. Mice from the second and third group were injected with IgG-Cyt and aCD45-Cyt therapies, respectively. Each sample represents cells from an individual mouse from this study.