Cutting edge: Critical role of intracellular osteopontin in antifungal innate immune responses

Makoto Inoue, Yasuhiro Moriwaki, Tomohiro Arikawa, Yu Hsun Chen, Young Joo Oh, Timothy Oliver, Mari L. Shinohara

Research output: Contribution to journalArticlepeer-review


We found that absence of osteopontin (OPN) in immunocompromised Rag2 -/- mice, which lack T and B cells, made the mice extremely susceptible to an opportunistic fungus Pneumocystis, although immunocompetent OPN-deficient mice could clear Pneumocystis as well as wild-type mice. OPN has been studied as an extracellular protein, and the role of an intracellular isoform of OPN (iOPN) is still largely unknown. In this study, we elucidated the mechanism by which iOPN was involved in antifungal innate immunity. First, iOPN was essential for cluster formation of fungal receptors that detect Pneumocystis, including dectin-1, TLR2, and mannose receptor. Second, iOPN played a role as an adaptor molecule in TLR2 and dectin-1 signaling pathways and mediated ERK activation and cytokine production by zymosan, which simultaneously activates TLR2 and dectin-1 pathways. Third, iOPN enhanced phagocytosis and clearance of Pneumocystis. Our study suggests the critical involvement of iOPN in antifungal innate immunity.

Original languageEnglish (US)
Pages (from-to)19-23
Number of pages5
JournalJournal of Immunology
Issue number1
StatePublished - Jan 1 2011
Externally publishedYes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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