RNAi suppression of recognition protein mediated immune responses in the tobacco hornworm Manduca sexta causes increased susceptibility to the insect pathogen Photorhabdus
Bacterial pathogens either hide from or overcome the immune response of their hosts. Here we show that two different species of insect pathogenic bacteria, Photorhabdus luminescens TT01 and Photorhabdus asymbiotica ATCC43949, were both recognized by the immune system of their host Manduca sexta, as...
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Published in | Developmental & Comparative Immunology Vol. 30; no. 12; pp. 1099 - 1107 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier Ltd
2006
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Subjects | |
Online Access | Get full text |
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Summary: | Bacterial pathogens either hide from or overcome the immune response of their hosts. Here we show that two different species of insect pathogenic bacteria,
Photorhabdus luminescens TT01 and
Photorhabdus asymbiotica ATCC43949, were both recognized by the immune system of their host
Manduca sexta, as indicated by a rapid increase in the levels of mRNAs encoding three different inducible microbial recognition proteins, Hemolin, Immulectin-2 and peptidoglycan recognition protein. RNA interference (RNAi)-mediated inhibition of expression (“knock-down”) of each of these genes at the level of both mRNA and protein was achieved through injection of double-stranded RNA (dsRNA). Knock-down of any one of these genes markedly decreased the ability of the insects to withstand infection when exposed to either species of
Photorhabdus, as measured by the rate at which infected insects died. RNAi against Immulectin-2 caused the greatest reduction in host resistance to infection. The decreased resistance to infection was associated with reduced hemolymph phenoloxidase activity. These results show not only that
Photorhabdus is recognized by the
Manduca sexta immune system but also that the insect's immune system plays an active, but ultimately ineffective, role in countering infection. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0145-305X 1879-0089 1365-2567 |
DOI: | 10.1016/j.dci.2006.02.008 |