Understanding Dendritic Cells and Their Role in Cutaneous Carcinoma and Cancer Immunotherapy
Current strategies for DC immunotherapy in the treatment of cutaneous carcinoma. (a) Direct in vivo DC vaccination involves the targeted delivery of tumor antigen to DCs by linking them to antibodies specific for a given DC surface molecule. Examples include CD205 for mDCs or Langerin/CD207 for LCs. (b) Epicutaneous immunization allows for the direct application of protein antigen to a disruption in the skin barrier, which will preferentially target LCs due to their predominance in the epidermis. (c) Ex vivo DC vaccination relies on the in vitro generation of immature DCs from hematopoietic progenitors or peripheral blood monocytes. DCs are then loaded with tumor antigen and reinfused into the patient. (d) Immunomodulatory therapy involves the application of topical agents that may directly regulate the immune response. Often they act as adjuvants to induce the activation and migration of LCs to nearby lymph nodes. Other effects include the TLR7/8-dependent recruitment of pDCs to the tumor region following imiquimod treatment.