Antigenics’ researchers have shown that the Oncophage vaccine, which consists of the HSP-peptide complexes derived from a patient’s tumor, interacts with the immune system’s antigen-presenting cells at the site of injection. From this point on, the steps involved in triggering specific immune response appear to be the same as those triggered naturally when extracellular HSPs send a danger signal to the immune system.

Specifically, the HSP complexes bind to the CD91 receptor on antigen-presenting cells (APCs), and are taken into the cells. The APCs then travel to the lymph nodes, where they re-present the antigenic peptides on their surfaces. This triggers a cancer-specific immune response, including stimulation of various immune cells and release of immune system chemicals called cytokines.