CD4 and neoplasm: In a breast cancer model, a recombinant fusogenic VSV variant carrying reovirus fusion-associated small transmembrane (FAST) proteins and the VSV(MΔ51) backbone (a more immunogenic variant of VSV) induced a significant increase in iNKT cells, NK cells, CD8+ and CD4+ T cells, and DCs in the tumor, compared to untreated and VSV-GFP-treated tumors [30], which is consistent with our observations of immune cell responses to VSV-NDV treatment.