Targeting tumor extracellular matrix activates the tumor-draining lymph nodes.

Disruption of the tumor extracellular matrix (ECM) may alter immune cell infiltration into the tumor and antitumor T cell priming in the tumor-draining lymph nodes (tdLNs). Here, we explore how intratumoral enzyme treatment (ET) of B16 melanoma tumors with ECM-depleting enzyme hyaluronidase alters adaptive and innate immune populations, including T cells, DCs, and macrophages, in the tumors and tdLNs. ET increased CD103 DC abundance in the tdLNs, as well as antigen presentation of a model tumor antigen ovalbumin (OVA), eliciting local OVA-specific CD8 T cell responses. Delivered in combination with a distant cryogel-based cancer vaccine, ET increased the systemic antigen-specific CD8 T cell response. By enhancing activity within the tdLN, ET may broadly support immunotherapies in generating tumor-specific immunity.