Pentraxin 3 Facilitates Shrimp-Allergic Responses in IgE-Activated Mast Cells

Background. Since food avoidance is currently the only way to prevent allergic reactions to shrimp, a better understanding of molecular events in the induction and progression of allergy, including food allergy, is needed for developing strategies to inhibit allergic responses. Pentraxin 3 (PTX3) is rapidly produced directly from inflammatory or damaged tissues and is involved in acute immunoinflammatory responses. However, the role of PTX3 in the development of immediate IgE-mediated shrimp allergy remains unknown. Methods. Wild-type BALB/c mice were immunized intraperitoneally and were challenged with shrimp extract. Serum IgE and PTX3 levels were analyzed. RBL-2H3 cells were stimulated with either dinitrophenyl (DNP) or serum of shrimp-allergic mice, and markers of degranulation, proinflammatory mediators, and phosphorylation of signal proteins were analyzed. We further examined the effect of PTX3 in shrimp extract-induced allergic responses in vitro and in vivo. Results. Mice with shrimp allergy had increased PTX3 levels in the serum and small intestine compared with healthy mice. PTX3 augmented degranulation, the production of proinflammatory mediators, and activation of the Akt and MAPK signaling pathways in mast cells upon DNP stimulation. Furthermore, the expression of transcription factor CCAAT/enhancer-binding protein delta (CEBPD) was elevated in PTX3-mediated mast cell activation. Finally, the PTX3 inhibitor RI37 could attenuate PTX3-induced degranulation, proinflammatory mediator expression, and phosphorylation of the Akt and MAPK signaling. Conclusions. The results suggested that PTX3 can facilitate allergic responses. Our data provide new insight to demonstrate that PTX3 is a cause of allergic inflammation and that RI37 can serve as a therapeutic agent in shrimp allergy.