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

Figure 4

PTX3 increases degranulation, production of inflammatory mediators, and activation of the FcεRI signaling pathways in RBL-2H3 cells mimicking shrimp allergy. (a) Three-to-four-week-old female BALB/c mice ( per group) were intraperitoneally sensitized with PBS, shrimp extract or recombinant tropomyosin peptides, and challenged by a high dose of shrimp extract. Using Al(OH)₃ as an adjuvant, shrimp allergy mice received either 10 mg of shrimp extract or 1 mg of tropomyosin peptides in PBS i.p. on days 1, 4, 7, 10, 13, 16, 19, and 22. Blood was collected after the challenge with 50 mg of shrimp extract on day 30. (b, c) Levels of serological total IgE and PTX3 were determined by ELISA. (d) RBL-2H3 cells were incubated with sera from the various groups overnight and further stimulated with shrimp extract for 15 min. β-hexosaminidase activity was determined as described in the Materials and Methods. (e) Effects of sera from the various groups as indicated on the mRNA levels of TNF-α, IL-4, IL-6, IL-13, and COX-2 in serum-treated RBL-2H3 cells. (f) Effects of sera from the various groups on FcεRI signaling pathways in serum-stimulated RBL-2H3 cells. Total lysates were harvested for western blot analysis using antibodies as indicated. The quantitative analysis of phosphorylated proteins is shown in the graph.

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