<i>S. japonicum</i> infection induced a shift in systemic cytokine profiles from pro-inflammation to anti-inflammation.

<p><i>S. japonicum</i> infection induced a shift in cytokine patterns from pro-inflammatory to anti-inflammatory. Splenocytes obtained from DBA/1 mice 12 weeks after CII immunization were cultured <i>in vitro</i> in RPMI 1640 containing 10% fetal calf serum with ConA (5 µg/ml) for 48 hrs. Supernatants were collected and analyzed for cytokine production by ELISA as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0023453#s4" target="_blank">Materials and Methods</a>. Note that the levels of the Th1 signature cytokine IFN-<i>γ</i> and the pro-inflammatory cytokines TNF-<i>α</i>, IL-1, IL-6 were lowered, while those of the Th2 signature cytokine IL-4 and IL-10 were enhanced in prior <i>S. japonicum</i>-infected mice. No differences were found between unisexual and bisexual infected mice. Data are expressed as means ± SD for duplicate cultures. Compared with CIA control group, *: <i>P</i><0.05; **: <i>P</i><0.01. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0023453#pone-0023453-g001" target="_blank">Figures 1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0023453#pone-0023453-g002" target="_blank">2</a> for other definitions.</p

Prior <i>S. japonicum</i> infection reduced the expression of immune mediators in inflammatory joints.

<p>Reduced pro-inflammatory cytokines expression in the focal joints in <i>S. japonicum</i> infected mice. The mRNA expression of cytokines and RANKL were quantified by Real time PCR as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0023453#s4" target="_blank">Materials and Methods</a>. Prior <i>S. japonicum infection balanced the pro- and anti-inflammatory cytokines and reduced the expression of RANKL in the local site. Values along the vertical axis represent relative expression levels normalized to β</i>-actin. Compared with CIA control group, *: <i>P</i><0.05; **: <i>P</i><0.001. Data are representative of three repeated experiments. Abbreviations: RANKL, receptor activator of NF-κB ligand. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0023453#pone-0023453-g001" target="_blank">Figure 1</a> for other definitions.</p

Effects of <i>S. japonicum</i> infection on anti-type-II collagen (anti-CII) antibody production.

<p><i>S. japonicum</i> infection alters the levels of auto-antibodies in CIA mice. Sera were taken from DBA/1 mice 12 weeks after CII immunization. The concentration of anti-CII IgG and its subtype antibodies were determined by ELISA. The levels of anti-CII IgG and its subtypes were elevated in CIA mice. Compared with uninfected CIA mice, prior schistosome infection significantly reduced the levels of IgG and IgG2a in the sera, while the level of IgG1 was elevated in the infected mice. However, there was no statistically significant difference in the post schistosome infected CIA mice. No difference was observed between unisexual and bisexual infected mice. Means ± SD data for each mouse are shown. Compared with CIA control group, *: <i>P</i><0.05; **: <i>P</i><0.01. Data are representative of three repeated experiments. Abbreviations: ELISA, enzyme linked immunosorbent assay. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0023453#pone-0023453-g001" target="_blank">Figure 1</a> for other definitions.</p

Effects of <i>S. japonicum</i> infection on the development of collagen-induced arthritis (CIA) in DBA/1 mice.

<p>Attenuated clinical manifestation of arthritis in prior <i>S. japonicum</i> infected mice. Mice were infected with <i>S. japonicum</i> 2 weeks prior to bovine type II collagen (CII) immunization or at the onset of disease. The severity (A) and incidence (B) of arthritis were assessed as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0023453#s4" target="_blank">Materials and Methods</a>. Data are expressed as means of the total scores for four limbs or the incidence of arthritis after CII immunization. (n = 12/group). Statistical analysis by one-way ANOVA with Bonferroni's multiple comparison tests or by log-rank test of Kaplan–Meier survival curves. The clinical score of each mouse was recorded every day from 14 d after primary CII immunization. The onset of arthritis was about 28 d after CII immunization, and the peak time of the onset was around 33–35 d after immunization. The clinical score and the survival curve only differ significantly between prior schistosome-infected CIA mice and uninfected control mice. The diseases were exacerbated in the established CIA mice at one week after bisexual cercariae challenging. group A = unisexual <i>S. japonicum</i> infection prior to CII immunization; group B = bisexual <i>S. japonicum</i> infection prior to CII immunization; group C = unisexual <i>S. japonicum</i> infection post CII immunization; group D = bisexual <i>S. japonicum</i> infection post CII immunization; group E = uninfected CIA control mice, group E = age-matched normal control mice. (C) (a), A normal mouse and (b) a Type-II collagen (CII)-immunized uninfected mouse. Note the presence of severe synovial hyperplasia, mononuclear cell infiltration and angiogenesis, and the destruction of cartilage, focal fibrotic ankylosis and stenosis of articular cavity in the CII-immunized uninfected mouse. The arrows indicate an area of cartilage and bone (calcaneus) destruction. (c and d), Prior unisexual and bisexual <i>S. japonicum</i> infected CIA mouse. (e and f), Unisexual and bisexual <i>S. japonicum</i> infected in an established CIA mouse. Note the marked reduction of cell influx. Neither severe synovitis nor synovial hyperplasia was observed. Abbreviations: <i>S. japonicum</i>, <i>Schistosoma japonicum</i>; CII, bovine Type-II collagen; B, bone (calcaneus); JS, joint space; C, cartilage; S, synovitis. Original magnification: 100×.</p

Effects of <i>S. japonicum</i> infection on splenocyte proliferation.

<p><i>S. japonicum</i> infection inhibited splenocyte proliferation <i>in vitro</i>. 12 weeks after CII immunization in DBA/1 mice, splenocytes were cultured in RPMI 1640 containing 10% fetal calf serum for 72 hrs in the presence of polyclonal (ConA 5 µg/ml) or antigen-specific stimuli (CII 50 µg/ml or 100 µg/ml), respectively. Splenocyte proliferation was analyzed by ³H-TdR. Proliferation data are presented as mean ± SE of c.p.m. values. Data are representative of three repeated experiments. Compared with CIA control group, *: <i>P</i><0.05; **: <i>P</i><0.001. Abbreviations: ³H-TdR, tritiated thymidin incorporation; c.p.m., counts per minute. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0023453#pone-0023453-g001" target="_blank">Figure 1</a> for other definitions.</p