Baculovirus infection influences host protein expression in two established insect cell lines

We identified host proteins that changed in response to host cell susceptibility to baculovirus infection. We used three baculovirus–host cell systems utilizing two cell lines derived from pupal ovaries, Hz-AM1 (from Helicoverpa zea) and Hv-AM1 (from Heliothis virescens). Hv-AM1 cells are permissive to Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and semi-permissive to H. zea single nucleopolyhedrovirus (HzSNPV). Hz-AM1 cells are non-permissive to AcMNPV. We challenged each cell line with baculovirus infection and after 24 h determined protein identities by MALDI TOF/TOF mass spectrometry. For Hv-AM1 cells, 21 proteins were identified, and for Hz-AM1 cells, 19 proteins were newly identified (with 8 others having been previously identified). In the permissive relationship, 18 of the proteins changed in expression by 70% or more in AcMNPV infected Hv-AM1 cells as compared with non-infected controls; 12 were significantly decreased and 6 cellular proteins were significantly increased. We also identified 3 virus-specific proteins. In the semi-permissive infections, eight proteins decreased by 2-fold or more. Non-permissive interactions did not lead to substantial changes in host cell protein expression. We hypothesize that some of these proteins act in determining host cell specificity for baculoviruses.