Related Experiment Video
Updated: Apr 17, 2026

A Galleria mellonella Oral Administration Model to Study Commensal-Induced Innate Immune Responses
Published on: March 21, 2019
Scavenger receptor B1 modulates antimicrobial peptide expression and cellular immunity against bacterial infection in
Zhaoyang Han1, He Zhang1, Yulin Liu1
1Department of Entomology, College of Plant Protection, Yangzhou University, Yangzhou, Jiangsu 225009, China.
Abstract:
Scavenger receptor class B (SR-B) is a class of transmembrane glycoproteins involved in insect innate immunity through the recognition of pathogen-associated molecular patterns (PAMPs). Although extensively studied in vertebrates, the precise molecular mechanisms by which SR-B mediates immune responses in insects remain unclear. In this study, we identified and characterized an SR-B member from Ostrinia furnacalis. We report that OfSR-B1 localizes to the hemocyte membrane of O. furnacalis, and its expression is upregulated following infection with Micrococcus luteus and Pseudomonas aeruginosa. In vitro assays demonstrated that recombinant OfSR-B1 protein binds to both Gram-positive and Gram-negative bacteria and promotes bacterial agglutination. Knockout of O. furnacalis OfSR-B1 suppressed the transcription of a calcium channel protein, and pre-incubation with an OfSR-B1 antibody inhibited bacteria-induced Ca2+ influx. Transcriptomic analysis revealed that OfSR-B1 knockout impaired intracellular signaling in the Toll pathway and phagocytosis. Following OfSR-B1 RNA interference or antibody blockade, the expression of genes related to the Toll pathway, antimicrobial peptides (Attacin and Gloverin), and phagocytosis decreased. Further phagocytosis assays confirmed that the loss of OfSR-B1 impaired hemocyte-mediated bacterial phagocytosis. Finally, the OfSR-B1 knockout reduced larval survival following bacterial infection. These findings elucidate the role of OfSR-B1 in bacterial recognition and its underlying immune mechanisms, providing valuable insights for the development of biopesticides targeting the OfSR-B1 protein.
Related Concept Videos
Antimicrobial Proteins
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...
Gene Regulation in Microbial Communities: Quorum Sensing
Receptor Downregulation in MVBs
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR...
Regulation of Bacterial Virulence
Transduction
Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...

