PTX3 expression is up-regulated following RRV infection in murine model.

<p>(A) 21-day-old C57BL/6 WT mice (<i>n</i> = 4–5 per group) were subcutaneously injected with 10⁴ PFU of RRV or PBS (mock). Mice were sacrificed at 2, 5, 10 and 15 dpi. Serum, quadriceps and ankle joints were harvested. PTX3 expression in serum of RRV- or mock-infected mice was determined by ELISA. (B) Transcriptional profile of PTX3 in quadriceps and ankle joint harvested from RRV- or mock-infected mice at various time points were determined by qRT-PCR. Data were normalized to <i>HPRT</i> and shown as fold expression relative to mock-infected. *<i>P</i> < 0.05, **<i>P</i> < 0.01, ***<i>P</i> < 0.001, two-way ANOVA, Bonferroni post-test. Data are presented as mean ± SEM and are representative of 2 independent experiments. (C) Histology of RRV-induced inflammation in quadriceps of WT mice was analyzed by IHC staining with anti-PTX3 antibody at 10 dpi. Arrows indicate abundance of inflammatory infiltrates. Images were taken at 20× magnification. Scale bar, 40 μm. (D) 21-day-old C57BL/6 WT (<i>n</i> = 2–3 per group) mice were infected subcutaneously with 10⁴ PFU RRV. Spleens were harvested at 2 dpi and were characterized and quantified by flow cytometry using the markers as described in Materials and Methods to determine mean fluorescence intensity (MFI) of PTX3 expression in total leukocytes, inflammatory monocytes, neutrophils, NK cells, T cells and B cells. Data are presented as mean ± SEM. **<i>P</i> < 0.01, ***<i>P</i> < 0.001, two-way ANOVA, Bonferroni post-test.