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作者 Pham, Linh Nguyen
書名 Specific memory in the Drosophila immune response is dependent on phagocytes
國際標準書號 9780549356127
book jacket
說明 125 p
附註 Source: Dissertation Abstracts International, Volume: 68-12, Section: B, page: 7799
Adviser: David S. Schneider
Thesis (Ph.D.)--Stanford University, 2008
All organisms have an innate immune response, but only vertebrates possess T cells and the ability to produce antibodies. It has been a long-standing assumption that invertebrate immune systems are not adaptive and respond identically to multiple challenges. In this thesis, I demonstrate that the fly innate immune response adapts to repeated challenges; flies pre-inoculated with dead S. pneumoniae are protected against a second, otherwise lethal dose. Although the underlying mechanisms are likely to be very different, this primed response is reminiscent to vaccine-induced protection in that it is highly specific (dead S. pneumoniae only protects against itself), persists for the life of the fly, and is dependent on phagocytic cells. Although not all microbial challenges induced this specific primed response, we find that a similar specific protection can be elicited by Beauveria bassiana, a natural fly pathogen
To characterize this primed response, we focused on S. pneumoniae -induced protection. The mechanism underlying this protective effect requires the Toll pathway, but activation of the Toll pathway is not sufficient for priming-induced protection. Although the imd, TNF (eiger), and JAK/STAT signaling pathways contribute to fighting S. pneumoniae infections, they are all dispensable for the primed response. We also characterized a novel gene, little wing, which is required for the primed response
In addition to the specific primed immune response, we also found that previously wounded flies exhibit an enhanced antimicrobial peptide (AMP) response. Wound-activated flies injected with PBS induce a higher level of AMPs more quickly upon a second injection of PBS. The peak of AMP transcription is shifted from 6 hours to 2 hours, and the level of AMP transcription in doubly wounded flies is higher than flies injected once with bacteria
Taken together, this body of work contradicts the paradigm that insect immune responses cannot adapt and will promote the search for similar responses overlooked in organisms with an adaptive immune response. Determining whether the innate immune system of vertebrates shares adaptive characteristics is of particular interest since immunocompromised individuals only possess an innate immune system
School code: 0212
Host Item Dissertation Abstracts International 68-12B
主題 Biology, Microbiology
Health Sciences, Immunology
Alt Author Stanford University
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