Vaccine-Based Immunotherapy from Novel Nanoparticle Systems. Researchers at the Texas Center for Cancer Nanomedicine (TCCN) are creating particle-based vaccines for cancer therapy. The particles carry molecules that stimulate immune cells and cancer antigens (proteins) that direct the immune response. This scanning electron microscope image shows dendritic cells, pseudo-colored in green, interacting with T cells, pseudo-colored in pink. The dendritic cells internalize the particles, process the antigens, and present peptides to T cells to direct immune responses.