Similarly to <i>BmToll9-1</i>, <i>BmToll9-2</i> Is a Positive Regulator of the Humoral Immune Response in the Silkworm, <i>Bombyx mori</i>

Toll receptors play important roles in the development and innate immunity of insects. Previously, we reported the immunological function of <i>BmToll9-2</i> in silkworm, <i>Bombyx mori</i>, larvae. In this study, we focused on the role of <i>BmToll9-2</i> as a re...

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Bibliographic Details
Main Authors: Jisheng Liu, Weijian Chen, Sihua Chen, Shuqiang Li, Luc Swevers
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Insects
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Online Access:https://www.mdpi.com/2075-4450/15/12/1005
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Summary:Toll receptors play important roles in the development and innate immunity of insects. Previously, we reported the immunological function of <i>BmToll9-2</i> in silkworm, <i>Bombyx mori</i>, larvae. In this study, we focused on the role of <i>BmToll9-2</i> as a regulator in the Toll signaling pathway. The expressions of most signaling genes in the Toll pathway, as well as immune effectors, were reduced after the RNAi of <i>BmToll9-2</i>. Coincidentally, hemolymph from <i>BmToll9-2</i>-silenced larvae exhibited decreased antibacterial activity in the growth of <i>Escherichia coli</i>, demonstrated either by growth curve or inhibitory zone experiments. The oral administration of heat-inactivated <i>E. coli</i> and <i>Staphylococcus aureus</i> following the RNAi of <i>BmToll9-2</i> up-regulated the expression of most signaling genes in the Toll pathway and downstream immune effectors. The above results indicate that <i>BmToll9-2</i> is positively involved in the Toll signaling pathway. As a positive regulator, <i>BmToll9-2</i> is shown to be activated preferentially against <i>E. coli</i> and, in turn, positively modulates the humoral immune response in antibacterial activity.
ISSN:2075-4450