Vaccinia virus oncolysate (VO)

Vaccinia virus oncolysate (VO) is a complex immunotherapeutic preparation consisting of the plasma membrane fragments of tumor cells that have been infected and subsequently lysed by the Vaccinia virus (Wallack et al., 1986, Cancer). This approach functions as a polyvalent cancer vaccine, where the Vaccinia virus acts as a potent biological adjuvant to enhance the host's immune recognition of tumor-associated antigens (TAAs) (Hersey et al., 1987, Ann Surg). By presenting tumor antigens in the context of a viral infection, the vaccine aims to overcome immune tolerance and stimulate a robust T-cell mediated anti-tumor response (Wallack et al., 1998, J Clin Oncol). Historically, VO was primarily investigated as an adjuvant therapy for patients with high-risk melanoma to prevent recurrence after surgical resection (Slingluff, 2011, Cancer J). While clinical trials demonstrated that VO could induce specific humoral and cellular immunity, its overall clinical efficacy was modest, leading to its replacement by more modern immunotherapies like checkpoint inhibitors (Wallack et al., 1998, J Clin Oncol). Today, the concept lives on in the development of recombinant oncolytic viruses that both lyse tumor cells and express specific immunostimulatory cytokines.

Other names

Vaccinia melanoma oncolysateVMOViral oncolysateVaccinia-lysed tumor cell vaccineVaccinia virus antigens

Induction of active specific immunotherapy by utilizing the vaccinia virus as a biological adjuvant to enhance the host's immune recognition and response against tumor-associated antigens present in the lysate.