The long term goal of this project is to gain a comprehensive understanding of the intimate associations of larval digenetic trematodes and gastropod mollusks. Larval digeneans and their secretory-excretory products (SEP) will be used as probes to understand how the molluscan internal defence system (IDS) recognizes and responds to intruders. Strategies employed by larval digeneans in subverting the molluscan IDS will also be investigated. In the process, a broader understanding of host-parasite associations and the evolution of internal defence systems will be gained. This project will also contribute information of potential relevance to the development of novel methods for controlling human schistosomes. Using the snail Biomphalaria glabrata and the trematode Echinostroma paraensei as primary model systems, the functional role of snail hemolymph polypeptides known to increase in abundance following infection and to precipitate parasite antigens will be studied. The gene encoding this parasite responsive molecule will be identified and characterized and its possible homology with other molecules assessed. Also, specific molecules within E. paraensei sporocyst SEP that directly affect the functional integrity of B. glabrata hemocytes will be identified. The genes producing relevant SEP components will be identified, sequenced and compared to other known genes. A series of studies is also proposed to determine if SEP has cytotoxic or mitogenic effects for hemocyte structure. A panel of six digenean and four snail species will be investigated to determine if SEP from each parasite specifically affects only hemocytes of compatible snails, and if parasites are more likely to be bound by hemocytes from incompatible than compatible snail hosts. This comparative study will serve to check the validity of results obtained with commonly-studied model systems, and will help to elucidate fundamental principles underlying the phenomenon of host specificity. Finally, using genes outlined in the above studies, the genomes of the six trematode and four snail species will be probed in search of related genes.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Tropical Medicine and Parasitology Study Section (TMP)
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University of New Mexico
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Hanington, Patrick C; Forys, Michelle A; Loker, Eric S (2012) A somatically diversified defense factor, FREP3, is a determinant of snail resistance to schistosome infection. PLoS Negl Trop Dis 6:e1591
Loker, Eric S (2012) Macroevolutionary Immunology: A Role for Immunity in the Diversification of Animal life. Front Immunol 3:25
Hanington, Patrick C; Zhang, Si-Ming (2011) The primary role of fibrinogen-related proteins in invertebrates is defense, not coagulation. J Innate Immun 3:17-27
Adema, Coen M; Hanington, Patrick C; Lun, Cheng-Man et al. (2010) Differential transcriptomic responses of Biomphalaria glabrata (Gastropoda, Mollusca) to bacteria and metazoan parasites, Schistosoma mansoni and Echinostoma paraensei (Digenea, Platyhelminthes). Mol Immunol 47:849-60
Loker, Eric S (2010) Gastropod immunobiology. Adv Exp Med Biol 708:17-43
Hanington, Patrick C; Lun, Cheng-Man; Adema, Coen M et al. (2010) Time series analysis of the transcriptional responses of Biomphalaria glabrata throughout the course of intramolluscan development of Schistosoma mansoni and Echinostoma paraensei. Int J Parasitol 40:819-31
Hanington, Patrick C; Forys, Michelle A; Dragoo, Jerry W et al. (2010) Role for a somatically diversified lectin in resistance of an invertebrate to parasite infection. Proc Natl Acad Sci U S A 107:21087-92
Hathaway, Jennifer J M; Adema, Coen M; Stout, Barbara A et al. (2010) Identification of protein components of egg masses indicates parental investment in immunoprotection of offspring by Biomphalaria glabrata (gastropoda, mollusca). Dev Comp Immunol 34:425-35
Zhang, Si-Ming; Nian, Hong; Wang, Bo et al. (2009) Schistosomin from the snail Biomphalaria glabrata: expression studies suggest no involvement in trematode-mediated castration. Mol Biochem Parasitol 165:79-86
Adema, Coen M; Luo, Mei-Zhong; Hanelt, Ben et al. (2006) A bacterial artificial chromosome library for Biomphalaria glabrata, intermediate snail host of Schistosoma mansoni. Mem Inst Oswaldo Cruz 101 Suppl 1:167-77

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