Bovine herpesvirus type 1 as a novel oncolytic virus.

Oncolytic virotherapy is a promising avenue of cancer gene therapy. Current vectors include human viruses that have been engineered to replicate in tumor cells or nonhuman viruses that are naturally oncotropic and preferentially replicate in tumor cells harboring defects in innate immune pathways such as the type 1 interferon (IFN) pathway. Bovine herpesvirus type 1 (BHV-1) is a species-specific herpesvirus closely related to the human herpes simplex virus type 1 (HSV-1). Although BHV-1 does not efficiently replicate in and affect cellular viability of normal human cells, it is capable of infecting and killing various immortalized and transformed human cell types. Surprisingly, BHV-1 infection of human cells fails to elicit IFN production at the mRNA or protein level and the ability of BHV-1 to kill immortalized and transformed human cells does not correlate with defects in IFN pathways. Furthermore, although some cross-reactivity between BHV-1 and HSV-1 exists, the majority of human antibody or serum samples tested failed to neutralize BHV-1 despite possessing HSV-1 neutralizing capacity. Thus, BHV-1 is a novel candidate oncolytic virus with a distinct mechanism of tumor targeting.