This entry is represented by Autographa californica nuclear polyhedrosis virus (AcMNPV) Orf68 (also known as per os infectivity factor 6, PIF6 or ac68). PIF6 is present in both the budded virus (BV) and the occluded-derived virus (ODV). The ac68 gene overlaps the lef3 gene which encodes the single-stranded DNA binding protein, and knockout experiments of ac68 have to ensure that a functional lef3 gene is present. In ac68KO experiments, viral DNA replication and BV levels were unaffected as were mortality rates if caterpillars were injected with BV directly into the hemolymph bypassing the gut. However, in oral bioassays the ac68KO occlusion bodies failed to kill larvae, indicating that PIF6 is a per os infectivity factor.