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Updated: Mar 12, 2026
Trichuris muris Infection: A Model of Type 2 Immunity and Inflammation in the Gut
Published on: May 24, 2011
Microscopic investigation of AcMNPV infection in the Trichoplusia ni midgut
Muhammad Afzal Javed1, Stephanie Harris1, Leslie G Willis2
1Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, Saskatoon, SK S7N 0X2, Canada.
Abstract:
Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is the type species for the genus Alphabaculovirus in the family Baculoviridae. In nature, AcMNPV infection begins with ingestion of viral occlusion bodies (OBs) from which occlusion-derived viruses (ODV) are released to infect midgut cells. This study explored the early stages of Trichoplusia ni midgut infection using recombinant viruses expressing green fluorescent protein (GFP) and/or a VP39-mCherry fusion protein under the control of early and late promoters, respectively. Using a recombinant ie1:GFP virus, the anterior midgut region was identified as the predominant site for primary infection. Infection of midguts using the GFP-VP39mCherry-dual labelled recombinant virus revealed that active viral replication and cell-to-cell spread was required for the formation of infection foci and the subsequent spread to uninfected midgut cells and tracheoblasts. The spread of the infection from primary infected cells to secondary cells within the midgut was shown to be dependent upon the membrane fusion protein GP64.
Insights
Autographa californica multiple nucleopolyhedrovirus (AcMNPV) primarily infects the anterior midgut of Trichoplusia ni. Viral replication and GP64 protein are crucial for AcMNPV cell-to-cell spread within the insect.
Area of Science:
- Virology
- Insect Pathology
- Molecular Biology
Background:
- Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a key baculovirus infecting Lepidoptera.
- Baculovirus infection initiates with ingestion of occlusion bodies (OBs), releasing occlusion-derived virions (ODV) to infect midgut cells.
Purpose of the Study:
- To investigate the early infection stages of AcMNPV in Trichoplusia ni midgut.
- To identify the primary infection sites and mechanisms of viral spread within the host.
Main Methods:
- Utilized recombinant AcMNPV expressing green fluorescent protein (GFP) and VP39-mCherry fusion protein.
- Employed fluorescence microscopy to track viral infection and spread in T. ni midgut tissues.
- Examined the role of the GP64 protein in viral dissemination.
Main Results:
- The anterior midgut was identified as the primary site of AcMNPV infection.
- Active viral replication and cell-to-cell movement are essential for forming infection foci.
- The membrane fusion protein GP64 is critical for the spread of infection from primary to secondary midgut cells.
Conclusions:
- AcMNPV establishes primary infection in the anterior midgut of T. ni.
- Viral replication and GP64-mediated cell fusion drive AcMNPV dissemination within the host.
- Understanding these early events is vital for baculovirus-based pest control strategies.
