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Published on: October 4, 2024
Silkworm plasmatocytes are more resistant than other hemocyte morphotypes to Bombyx mori nucleopolyhedrovirus
Takanori Hori1, Takashi Kiuchi, Toru Shimada
1Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.
Abstract:
Differences in the viral susceptibility of multiple insect hemocyte morphotypes have not been investigated to date. In this study, a Bombyx mori nucleopolyhedrovirus (BmNPV) derivative possessing a Drosophila hsp70 promoter-driven green fluorescent protein (GFP) gene was used to observe NPV tropism of B. mori larval hemocytes. The experiments clearly revealed that there were fewer GFP-positive plasmatocytes than those observed in other types of hemocytes, such as granulocytes, oenocytoids, and spherulocytes, when infected via the intrahemocoelic or oral route. Our results indicate that silkworm plasmatocytes are more resistant than other hemocyte morphotypes to BmNPV infection.
Insights
Silkworm plasmatocytes show greater resistance to Bombyx mori nucleopolyhedrovirus (BmNPV) infection compared to other hemocyte types. This study investigated viral tropism in insect hemocytes, revealing differential susceptibility.
Area of Science:
- Entomology
- Virology
- Cell Biology
Background:
- Insect hemocytes are crucial for immune responses.
- Understanding viral tropism in hemocytes is vital for insect disease management.
- Previous studies have not detailed viral susceptibility across different insect hemocyte morphotypes.
Purpose of the Study:
- To investigate the differential susceptibility of Bombyx mori hemocyte morphotypes to Bombyx mori nucleopolyhedrovirus (BmNPV).
- To determine the tropism of BmNPV within various hemocyte populations in silkworm larvae.
Main Methods:
- Utilized a BmNPV derivative engineered with a green fluorescent protein (GFP) reporter gene under the control of the Drosophila hsp70 promoter.
- Infected silkworm larvae via intrahemocoelic and oral routes.
- Quantified GFP expression in different hemocyte morphotypes (plasmatocytes, granulocytes, oenocytoids, spherulocytes) to assess viral infection.
Main Results:
- Fewer GFP-positive plasmatocytes were observed compared to granulocytes, oenocytoids, and spherulocytes.
- Differential susceptibility to BmNPV infection was evident across hemocyte morphotypes.
- Plasmatocytes exhibited significantly lower infection rates than other hemocyte types.
Conclusions:
- Silkworm plasmatocytes are more resistant to BmNPV infection than other hemocyte morphotypes.
- This finding contributes to understanding host-pathogen interactions in insects.
- Highlights the importance of hemocyte heterogeneity in antiviral defense mechanisms.
