biostudies-literatureNaumenko VGouvernement du Canada | Instituts de Recherche en Santé du Canada | CIHR Skin Research Training CentreCanadian Cancer Society Research InstituteCIHR1385https://www.ebi.ac.uk/biostudies/studies/S-EPMC9761050biostudies-literatureUnknown5(1)There is debate in the field of oncolytic virus (OV) therapy, whether a single viral dose, or multiple administrations, is better for tumor control. Using intravital microscopy, we describe the fate of vesicular stomatitis virus (VSV) delivered systemically as a first or a second dose. Following primary administration, VSV binds to the endothelium, initiates tumor infection and activates a proinflammatory response. This initial OV dose induces neutrophil migration into the tumor and limits viral replication. OV administered as a second dose fails to infect the tumor and is captured by intravascular monocytes. Despite a lack of direct infection, this second viral dose, in a monocyte-dependent fashion, enhances and sustains infection by the first viral dose, promotes CD8 T cell recruitment, Communications biologyRepeated dosing improves oncolytic rhabdovirus therapy in mice via interactions with intravascular monocytes.PMC9761050#DF-18-5#420828Mah LKKim DChekhonin VPKaul EKTse MRajwani JRakic AMahoney DJNaumenko VDastidar HTurk MZhang CJenne CNDavis RPVan SfalseRepeated dosing improves oncolytic rhabdovirus therapy in mice via interactions with intravascular monocytes.There is debate in the field of oncolytic virus (OV) therapy, whether a single viral dose, or multiple administrations, is better for tumor control. Using intravital microscopy, we describe the fate of vesicular stomatitis virus (VSV) delivered systemically as a first or a second dose. Following primary administration, VSV binds to the endothelium, initiates tumor infection and activates a proinflammatory response. This initial OV dose induces neutrophil migration into the tumor and limits viral replication. OV administered as a second dose fails to infect the tumor and is captured by intravascular monocytes. Despite a lack of direct infection, this second viral dose, in a monocyte-dependent fashion, enhances and sustains infection by the first viral dose, promotes CD8 T cell recruitment, 2022-01-01T00:00:00Z2022 Dec2026-05-29T04:34:16.544Z2025-04-07T01:57:07.704ZS-EPMC97610503653609710.1038/s42003-022-04254-3