Abstract
We characterize a novel pathogen recognition protein obtained from the lepidopteran Galleria mellonella. This protein recognizes Escherichia coli, Micrococcus luteus, and Candida albicans via specific binding to lipopolysaccharides, lipoteichoic acid, and beta-1,3-glucan, respectively. As a multiligand receptor capable of coping with a broad variety of invading pathogens, it is constitutively produced in the fat body, midgut, and integument but not in the hemocytes and is secreted into the hemolymph. The protein was confirmed to be relevant to cellular immune response and to further function as an opsonin that promotes the uptake of invading microorganisms into hemocytes. Our data reveal that the mechanism by which a multiligand receptor recognizes microorganisms contributes substantially to their phagocytosis by hemocytes. A better understanding of an opsonin with the required repertoire for detecting diverse invaders might provide us with critical insights into the mechanisms underlying insect phagocytosis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Candida albicans / metabolism
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Candida albicans / physiology
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Escherichia coli / metabolism
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Escherichia coli / physiology
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Flow Cytometry
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Hemocytes / metabolism
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Hemocytes / microbiology
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Insect Proteins / chemistry
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Insect Proteins / genetics
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Insect Proteins / metabolism*
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Larva / metabolism
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Larva / microbiology
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Lepidoptera / metabolism*
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Lepidoptera / microbiology*
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Lipopolysaccharides / metabolism
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Opsonin Proteins / chemistry
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Opsonin Proteins / genetics
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Opsonin Proteins / metabolism*
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Phagocytosis / genetics
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Phagocytosis / physiology*
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Protein Binding
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Receptors, Pattern Recognition / chemistry
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Receptors, Pattern Recognition / genetics
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Receptors, Pattern Recognition / metabolism
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Reverse Transcriptase Polymerase Chain Reaction
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Teichoic Acids / metabolism
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Tissue Culture Techniques
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beta-Glucans / metabolism
Substances
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Insect Proteins
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Lipopolysaccharides
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Opsonin Proteins
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Receptors, Pattern Recognition
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Teichoic Acids
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beta-Glucans
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lipoteichoic acid
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beta-1,3-glucan