Transplantation immune responses: Biology, challenges, and opportunities using biomaterials

The organs or cells transplantation is well-established in clinics. However, despite the increasing success rates and the broadening of various transplantation techniques, a key challenge is the requirement of life-long systemic immunosuppression to prevent rejection. Therefore, it is necessary to develop novel immuno-engineering strategies that can overcome the drawbacks of conventional immune cell depletion or immunosuppressive agents. In recent years, engineered biomaterials have been expanded toward localized and controlled release of immunomodulatory agents to decrease the effective dose and frequency of drug administration, mainly through immuno-engineering at the transplantation site. In this review, we concisely address a general overview of mechanisms involved in immune tolerance and rejection, followed by challenges within current therapeutic regimens, and then discuss recent developments on potent biomaterial-based immunoengineering strategies to prolong graft survival.

Automated summary

Organ or cell transplantation is widely used in clinical practice. However, the need for lifelong immunosuppression remains a major challenge. Engineered biomaterials have emerged as a promising strategy for localized and controlled release of immunomodulatory agents, enabling decreased drug administration frequency and dose. This review provides an overview of immune tolerance and rejection mechanisms, discusses current therapeutic challenges, and highlights recent advancements in biomaterial-based immunoengineering strategies for prolonged graft survival.