CD4 and neoplasm: Syncytia formation, which is a notable characteristic of the IHD-W strain, is likely to induce immunogenic cell death33 and consequently activate antitumor immune cells in the tumor microenvironment.30 Intratumoral administration of KLS-3010 in the LLC1 syngeneic mouse model increased the number of lymphocytes, including CD8+ and CD4+ T cells, in the tumor at 5 days after injection.