| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2015: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2014: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2013: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Outline of Final Research Achievements |
Nontypeable Haemophilus influenzae (NTHi) is associated with chronic otitis media (COM). In this study, we generated a murine model of COM by using Eustachian tube obstruction and NTHi inoculation into the tympanic bulla, and we investigated the relationship between regulatory T (T reg) cells and chronic inflammation in the middle ear. Middle ear effusions (MEEs) and middle ear mucosae (MEM) were collected at days 3 and 14 and at 1 and 2 months after inoculation. CD4+ CD25+ FoxP3+ T reg cells accumulated in the middle ear, and the percentage of T reg cells in the MEM increased for up to 2 months after inoculation. T reg cell depletion induced a 99.9% reduction of bacteria counts in MEEs and also significantly reduced the ratio of NTHi culture-positive MEE. The levels of these cytokines were also reduced in MEEs. In summary, we developed a murine model of COM and our findings indicate that T reg cells confer infectious tolerance to NTHi in the middle ear.
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