Abstract
Much attention has been focused on oncolytic viruses, which specifically infect and kill tumor cells without apparent cytotoxicity in normal cells, as a novel anticancer agent. In 2021, a recombinant oncolytic herpesvirus simplex virus （HSV）-1 was approved in Japan（conditional and time-limited approval）. Recent studies demonstrated that oncolytic viruses induce not only activation of innate immunity, but also release of neoantigens and damage-associated molecular patterns（DAMPs） from infected tumor cells, leading to efficient activation of antitumor immunity, which contributes to the antitumor effects of oncolytic viruses. In addition, several studies reported that combination therapy of oncolytic viruses and cancer immunotherapy, including immune checkpoint inhibitors, exhibits superior synergistic therapeutic effects on various types of cancers. In this review, we introduce oncolytic virus-mediated activation of antitumor immunity and combination therapy with cancer immunotherapy.
