Role of complement and Fcγ receptors in the protective activity of the long pentraxin PTX3 against Aspergillus fumigatus

F Moalli, A Doni, L Deban, T Zelante… - Blood, The Journal …, 2010 - ashpublications.org
F Moalli, A Doni, L Deban, T Zelante, S Zagarella, B Bottazzi, L Romani, A Mantovani
Blood, The Journal of the American Society of Hematology, 2010ashpublications.org
Abstract Pentraxin 3 (PTX3) is a soluble pattern recognition molecule playing a
nonredundant role in resistance against Aspergillus fumigatus. The present study was
designed to investigate the molecular pathways involved in the opsonic activity of PTX3. The
PTX3 N-terminal domain was responsible for conidia recognition, but the full-length
molecule was necessary for opsonic activity. The PTX3-dependent pathway of enhanced
neutrophil phagocytic activity involved complement activation via the alternative pathway; …
Abstract
Pentraxin 3 (PTX3) is a soluble pattern recognition molecule playing a nonredundant role in resistance against Aspergillus fumigatus. The present study was designed to investigate the molecular pathways involved in the opsonic activity of PTX3. The PTX3 N-terminal domain was responsible for conidia recognition, but the full-length molecule was necessary for opsonic activity. The PTX3-dependent pathway of enhanced neutrophil phagocytic activity involved complement activation via the alternative pathway; Fcγ receptor (FcγR) IIA/CD32 recognition of PTX3-sensitized conidia and complement receptor 3 (CR3) activation; and CR3 and CD32 localization to the phagocytic cup. Gene targeted mice (ptx3, FcR common γ chain, C3, C1q) validated the in vivo relevance of the pathway. In particular, the protective activity of exogenous PTX3 against A fumigatus was abolished in FcR common γ chain-deficient mice. Thus, the opsonic and antifungal activity of PTX3 is at the crossroad between complement, complement receptor 3-, and FcγR-mediated recognition. Because short pentraxins (eg, C-reactive protein) interact with complement and FcγR, the present results may have general significance for the mode of action of these components of the humoral arm of innate immunity.
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