**4. Therapeutic Outcomes of Exogenous TCL Delivery Using Various Biomaterials**

Exogenous TCL delivery using various multifunctional biomaterials through in vivo administration has been utilized in cancer immunotherapy. In particular, exogenous TCL delivery induced APC-dependent enhancement and the effective orchestration of adaptive immune responses by (1) augmenting in vivo DC maturation and activation, (2) increasing antigen presentation in DCs, and (3) further inducing T cells by interacting with multiple DCs. However, weak immunogenicity can be caused by a variety of factors, including (1) a lack of appropriate immunological DAMP signals [94], (2) inefficient delivery of relevant TAAs to resident in vivo DCs, and (3) the undesired degradation of antigen molecules during migration in the bloodstream and lymphatic system. Therefore, various delivery platforms with protective efficacy for cargo TCLs, and additional functionality to improve the immunogenicity of TCLs, have been investigated. As well as the intrinsic stimulation by biomaterial via direct immune cell regulation (i.e., DC activation and T cell proliferation) through the recognition of exogenous substances and their following interactions with immune cells [95], cargo TCL protection (i.e., preservation of its bioactivity upon in vivo administration) and subsequent augmentation under sustained DC activation, are technical advantages of biomaterial-based delivery platforms. The successful development of an efficient TCL delivery platform could represent a novel immune modulatory strategy for anticancer treatments, through the sequential accurate targeting processes of longer circulation with improved colloidal stability, sufficient delivery of TAAs in TCLs to lymph nodes, the sustained release of cargo TCLs, preservation of in vivo TCL bioactivity, and the enhanced cellular uptake of TAAs to DCs [96,97]. Hence, recent therapeutic approaches have focused on material-assisted TCL delivery platforms. This section reviews the current progress in TCL-mediated immune activation, anticancer treatment, and prospective applications of cancer vaccines.
