Submitted to: Society of Invertebrate Pathology
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2009
Publication Date: 8/19/2009
Citation: Terenius, O., Popham, H.J., Shelby, K. 2009. Bacterial but not Baculoviral Infections Stimulate Hemolin Expression in Helicoverpa zea and Heliothis virescens [abstract]. Society of Invertebrate Pathology. p. 91. Interpretive Summary:
Technical Abstract: Lepidopteran larvae are regularly infected by baculoviruses during feeding on infected plants. The differences in sensitivity to these infections can be substantial, even among closely related species. For example, the noctuids Cotton bollworm (Helicoverpa zea) and budworm (Heliothis virescens), which a couple of decades ago were considered to belong to the same genus, have a 1000-fold difference in sensitivity to Autographa californica multiple nucleopolyhedrovirus (AcMNPV) infection. Recent data were interpreted to indicate that the lepidopteran immunoglobulin protein, Hemolin, is activated upon viral injection and therefore to participate in anti-viral responses. To investigate whether Hemolin is activated after a natural virus infection specific transcription in fat bodies and hemocytes of H. zea and H. virescens larvae was monitored following per os infection with the baculovirus HzSNPV (H. zea single nucleopolyhedrovirus). Both moths showed strong Hemolin expression at 24 and 48 hours, which are time points that correspond to viral entry into hemocytes. However, the same expression pattern was seen in uninfected animals and coincided with ecdysone responses, previously known to induce Hemolin expression. In contrast, injection of lyophilized Micrococcus luteus resulted in increased Hemolin expression supporting a role for Hemolin as an immunoresponsive protein in these species. The combined data are consistent with the suggestion that while Hemolin seems to participate in the response to virus infection in the superfamily Bombycoidea, this is not true in the Noctuoidea.