ICOS and neoplasm: In other aspects, several attempts have been made to stimulate anti-tumor activity and/or to eliminate immune-threatening suppressors: the development of agonistic antibodies against costimulatory receptors (ICOS, GITR, 4-1BB, etc.)121,122, therapeutic vaccines that induce immune responses to tumor-specific antigen123,124, and agents that remove suppressive myeloid cells (MDSC, M2 macrophage, tolerogenic DC, etc.)125,126.