Serum Amyloid P Aids Complement-Mediated Immunity to Streptococcus pneumoniae

The physiological functions of the acute phase protein serum amyloid P (SAP) component are not well defined, although they are likely to be important, as no natural state of SAP deficiency has been reported. We have investigated the role of SAP for innate immunity to the important human pathogen Streptococcus pneumoniae. Using flow cytometry assays, we show that SAP binds to S. pneumoniae, increases classical pathway–dependent deposition of complement on the bacteria, and improves the efficiency of phagocytosis. As a consequence, in mouse models of infection, mice genetically engineered to be SAP-deficient had an impaired early inflammatory response to S. pneumoniae pneumonia and were unable to control bacterial replication, leading to the rapid development of fatal infection. Complement deposition, phagocytosis, and control of S. pneumoniae pneumonia were all improved by complementation with human SAP. These results demonstrate a novel and physiologically significant role for SAP for complement-mediated immunity against an important bacterial pathogen, and provide further evidence for the importance of the classical complement pathway for innate immunity

TGF-β Isoform Specific Regulation of Airway Inflammation and Remodelling in a Murine Model of Asthma

The TGF-β family of mediators are thought to play important roles in the regulation of inflammation and airway remodelling in asthma. All three mammalian isoforms of TGF-β, TGF-β1–3, are expressed in the airways and TGF-β1 and -β2 are increased in asthma. However, there is little information on the specific roles of individual TGF-β isoforms. In this study we assess the roles of TGF-β1 and TGF-β2 in the regulation of allergen-induced airway inflammation and remodelling associated with asthma, using a validated murine model of ovalbumin sensitization and challenge, and isoform specific TGF-β neutralising antibodies. Antibodies to both isoforms inhibited TGF-β mediated Smad signalling. Anti-TGF-β1 and anti-TGF-β2 inhibited ovalbumin-induced sub-epithelial collagen deposition but anti-TGF-β1 also specifically regulated airway and fibroblast decorin deposition by TGF-β1. Neither antibody affected the allergen-induced increase in sub-epithelial fibroblast-like cells. Anti- TGF-β1 also specifically inhibited ovalbumin-induced increases in monocyte/macrophage recruitment. Whereas, both TGF-β1 and TGF-β2 were involved in regulating allergen-induced increases in eosinophil and lymphocyte numbers. These data show that TGF-β1 and TGF-β2 exhibit a combination of specific and shared roles in the regulation of allergen-induced airway inflammation and remodelling. They also provide evidence in support of the potential for therapeutic regulation of specific subsets of cells and extracellular matrix proteins associated with inflammation and remodelling in airway diseases such as asthma and COPD, as well as other fibroproliferative diseases

The Importance of Context and Cognitive Agency in Developing Police Knowledge: Going Beyond the Police Science Discourse

This paper argues the current exposition of police knowledge through the discourses of police science and evidenced based policing (EBP) leads to exaggerated claims about what is, and can be, known in policing. This new orthodoxy underestimates the challenges of applying knowledge within culturally-mediated police practice. The paper draws upon virtue epistemology highlighting the role cognitive agency plays in establishing knowledge claims. We challenge the assumption that it is possible to derive what works in all instances of certain aspects of policing and suggest it would be more apt to speak about what worked within a specific police context

Clearance of the ST2 S. pneumoniae Strain from Wild-Type and <i>Apcs</i>^−/− Mice Inoculated Intravenously with 1.0 × 10⁶ cfu

<div><p>Each data point represents log₁₀ cfu/ml results for a single mouse, with the bar showing the median for each group.</p><p>(A) Results for blood 2 h after inoculation.</p><p>(B) Results for blood 4 h after inoculation.</p><p>(C) Results for spleen homogenates 4 h after inoculation. Data is obtained from one experiment that is representative of two separate experiments.</p><p><i>p</i>-Values for Mann–Whitney <i>U</i> comparisons between wild-type and <i>Apcs</i>^−/− mice are given below the title for each panel.</p></div

Binding of hSAP to ST2, ST4, and ST23F Strains of S. pneumoniae

<div><p>(A) Results of whole-cell ELISAs presented as maximum ODs after incubation with different concentrations of hSAP (given below each column as μg/ml), using the E. coli O111:B4 strain as a negative control. Error bars represent SDs, and asterisks mark significant <i>p</i>-values for comparisons of results for S. pneumoniae in 20 μg/ml hSAP versus medium alone (2-tailed <i>t</i> tests, *<i>p</i> < 0.01, ***<i>p</i> < 0.0001).</p><p>(B) Examples of flow cytometry histograms demonstrating hSAP binding to the surface of the three different S. pneumoniae strains, the E. coli O111:B4 strain, and the S. pyogenes H372 strain (positive control) after incubation in human serum.</p><p>(C) Effect of different concentrations of EDTA on SAP binding to the ST2 S. pneumoniae strain in human serum. Error bars represent SDs, and asterisks mark significant <i>p</i>-values for comparisons of results for EDTA versus serum alone (2-tailed <i>t</i> tests, ***<i>p</i> < 0.0001).</p><p>(D) Effect of addition of 100 mM PC on SAP and CRP binding to the ST2 S. pneumoniae strain in human serum. Grey columns, results for human serum; white columns, results for human serum in the presence of PC. Addition of 100 mM bovine serum albumin had no effect on SAP binding (unpublished data). Error bars represent SDs, and <i>p</i>-values are indicated above the columns.</p><p>(E) Examples of flow cytometry histograms demonstrating inhibition of hSAP binding to the surface of the ST2 S. pneumoniae strains by addition of 100 mM PC to human serum.</p></div

Effects of SAP on C3b Deposition on S. pneumoniae Measured Using Flow Cytometry

<div><p>(A) Time course of the proportion of ST2 S. pneumoniae bacteria positive for C3b after incubation in serum from wild-type and <i>Apcs^−/−</i> mice. For the comparison of results for wild-type versus <i>Apcs^−/−</i> mice, <i>p</i> < 0.001 at all time points from 1 to 20 min.</p><p>(B and C) Proportion of ST4 (B) and ST23F (C) S. pneumoniae bacteria positive for C3b after incubation for 20 min in serum from wild-type and <i>Apcs^−/−</i> mice.</p><p>(D and E) Examples of flow cytometry histograms of C3b deposition on ST2 (D) and ST23F (E) S. pneumoniae strains after incubation in PBS or serum from wild-type or <i>Apcs^−/−</i> mice.</p><p>(F) Effect on the proportion of ST2 S. pneumoniae positive for C3b of addition of 10 μg/ml hSAP to serum from <i>Apcs^−/−</i> mice.</p><p>(G) Effect on the proportion of ST2 S. pneumoniae positive for C3b of addition of an equal volume of serum from wild-type mice to serum from <i>Apcs^−/−</i> mice.</p><p>(H) Effect of addition of hSAP (50 μg/ml, white column) on C3b deposition on the ST2 S. pneumoniae strain in serum from <i>Apcs</i>^−/−<i>.C1qa</i>^−/− mice. Grey columns, results for <i>Apcs</i>^−/−<i>.C1qa</i>^−/− serum; white columns, results for <i>Apcs</i>^−/−<i>.C1qa</i>^−/− serum in the presence of hSAP.</p><p>For panels (A–C) and (F–H), error bars represent SDs, and in (A) when not visible are too small to be seen outside of the symbol. <i>p</i>-Values are calculated using 2-tailed <i>t</i> tests.</p></div

Effect of SAP on Phagocytosis of S. pneumoniae

<div><p>(A–C) Phagocytosis (presented as proportion of HL60 cells associated with fluorescent bacteria) of (A) ST2, (B) ST4, and (C) ST23F after incubation in different dilutions of serum from wild-type (circles) or <i>Apcs^−/−</i> (squares) mice. Results for incubation in HBSS are shown by the triangle symbol, and for the ST2 strain the results for a 50:50 mix of serum from wild-type and <i>Apcs^−/−</i> mice (diamonds) are also included.</p><p>(D) Example of a flow cytometry histogram of phagocytosis of ST2 S. pneumoniae by HL60 cells after incubation in HBSS or serum from wild-type or <i>Apcs^−/−</i> mice.</p><p>(E) Effect of addition of 5 or 50 μg/ml exogenous hSAP on phagocytosis of the ST2 S. pneumoniae strain in serum from <i>Apcs^−/−</i> mice.</p><p>(F) Effect of addition of hSAP (50 μg/ml) on phagocytosis of the ST2 S. pneumoniae strain in serum from <i>Apcs</i>^−/−<i>.C1qa</i>^−/− mice. Grey column, results for <i>Apcs</i>^−/−<i>.C1qa</i>^−/− serum; white column, results for <i>Apcs</i>^−/−<i>.C1qa</i>^−/− serum in the presence of hSAP. For panels (A–C), (E), and (F), asterisks mark significant <i>p</i>-values for comparisons of results for wild-type or mixed serum to <i>Apcs^−/−</i> serum (2-tailed <i>t</i> tests, *<i>p</i> < 0.01, **<i>p</i> < 0.001, ***<i>p</i> < 0.0001). All error bars represent SDs and when not visible are too small to be seen outside the symbol.</p></div