| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
Mucus is closely contact with gastrointestinal parasites reside in the gut and has been recognized as a platform where protective immune responses are expressed against the parasites. Adult worms of a rodent gastrointestinal nematode, Nippostrongylus brasiliensis, were intraduodenally challenged into mice that were given subcutaneous infection with infective larvae of the parasite 10 days before and terminated the intestinal infection. This experimental system is suitable to investigate the role of T-cell induced mucins for immune-mediated worm expulsion. Although almost the all worms were expelled by 24 hr after challenge, substantial number of challenged worms was recovered from the small intestine up to 6 hr after challenge. Second intraduodenal challenge was performed 18 hr after the first challenge when primed mucins were actively discharged. Again secondary challenged worms were recovered in the same level to that of the first challenge. These results suggested that primed mucins
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allowed temporally the attainment and adhesion of the challenged adult worms, but finally prevented the establishment from the gut (Ishiwata and Watanabe, 2006). This indicates that primed mucins have some physiological effects on the adult worms dwelling in the mucosa and resisting the natural flow of intestinal contents propelled by peristaltic contractions. Any reduction in the available energy in adult worms would impair this anchoring ability and promote expulsion from the gut. Therefore, energy metabolism of adult worms was measured by employing the CellTiter-Glo^<【○!R】> Luminescent Cell Viability Assay which determines the number of alive cells in culture via detecting fluorescence based on quantitation of ATP in cells (Ishiwata and Watanabe, in press). The study suggested that energy metabolism of adult worms was affected by the environment around the worms, although relevance of host immunity to the energy metabolism was not directly demonstrated. Adult nematodes are undoubtedly expelled by host immunity from the gut, but the attack is not lethal to the parasites. Thus, above results, which suggest that physiological activities of the worms are affected by host factors, are logically acceptable, although convincing evidences demonstrating direct implications of mucins on adult N. brasiliensis are under study. Less
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