Effects of Expression of Streptococcus pneumoniae PspC on the Ability of Streptococcus mitis to Evade Complement-Mediated Immunity

Streptococcus pneumoniae and Streptococcus mitis are genetically closely related and both frequently colonise the naso-oropharynx, yet S. pneumoniae is a common cause of invasive infections whereas S. mitis is only weakly pathogenic. We hypothesise that sensitivity to innate immunity may underlie these differences in virulence phenotype. We compared the sensitivity of S. pneumoniae and S. mitis strains to complement-mediated immunity, demonstrating S. mitis strains were susceptible to complement-mediated opsonophagocytosis. S. pneumoniae resistance to complement is partially dependent on binding of the complement regulator Factor H by the surface protein PspC. However, S. mitis was unable to bind factor H. The S. pneumoniae TIGR4 strain pspC was expressed in the S. mitis SK142 strain to create a S. mitis pspC+ strain. Immunoblots demonstrated the S. mitis pspC+ strain expressed PspC, and flow cytometry confirmed this resulted in Factor H binding to S. mitis, reduced susceptibility to complement and improved survival in whole human blood compared to the wild-type S. mitis strain. However, in mouse models the S. mitis pspC+ strain remained unable to establish persistent infection. Unlike S. pneumoniae strains, culture in serum or blood did not support increased CFU of the S. mitis strains. These results suggest S. mitis is highly sensitive to opsonisation with complement partially due to an inability to bind Factor H, but even when complement sensitivity was reduced by expression of pspC, poor growth in physiological fluid limited the virulence of S. mitis in mice

Improving Implementation: Building Research Capacity in Maternal, Neonatal, and Child Health in Africa

As part of a series on maternal, neonatal, and child health in sub-Saharan Africa, Valerie Snewin and colleagues discuss the challenges of implementation and research capacity in Africa

Calprotectin — A Novel Marker of Obesity

BACKGROUND: The two inflammatory molecules, S100A8 and S100A9, form a heterodimer, calprotectin. Plasma calprotectin levels are elevated in various inflammatory disorders. We hypothesized that plasma calprotectin levels would be increased in subjects with low-grade systemic inflammation i.e. either obese subjects or subjects with type 2 diabetes. METHODOLOGY/PRINCIPAL FINDINGS: Plasma calprotectin and skeletal muscle S100A8 mRNA levels were measured in a cohort consisting of 199 subjects divided into four groups depending on presence or absence of type 2 diabetes (T2D), and presence or absence of obesity. There was a significant interaction between obesity and T2D (p = 0.012). Plasma calprotectin was increased in obese relative to non-obese controls (p<0.0001), whereas it did not differ between obese and non-obese patients with T2D (p = 0.62). S100A8 mRNA levels in skeletal muscle were not influenced by obesity or T2D. Multivariate regression analysis (adjusting for age, sex, smoking and HOMA2-IR) showed plasma calprotectin to be strongly associated with BMI, even when further adjusted for fitness, CRP, TNF-alpha or neutrophil number. CONCLUSIONS/SIGNIFICANCE: Plasma calprotectin is a marker of obesity in individuals without type 2 diabetes

Mannose 6-Phosphate Receptor and Sortilin Mediated Endocytosis of α-Galactosidase A in Kidney Endothelial Cells

Prominent vasculopathy in Fabry disease patients is caused by excessive intracellular accumulation of globotriaosylceramide (GL-3) throughout the vascular endothelial cells causing progressive cerebrovascular, cardiac and renal impairments. The vascular lesions lead to myocardial ischemia, atherogenesis, stroke, aneurysm, thrombosis, and nephropathy. Hence, injury to the endothelial cells in the kidney is a key mechanism in human glomerular disease and endothelial cell repair is an important therapeutic target. We investigated the mechanism of uptake of α-galactosidase A (α-Gal A) in renal endothelial cells, in order to clarify if the recombinant enzyme is targeted to the lysosomes via the universal mannose 6-phosphate receptor (M6PR) and possibly other receptors. Immunohistochemical localization of infused recombinant α-Gal A in a renal biopsy from a classic Fabry disease patient showed that recombinant protein localize in the endothelial cells of the kidney. Affinity purification studies using α-Gal A resins identified M6PR and sortilin as α-Gal A receptors in cultured glomerular endothelial cells. Immunohistochemical analyses of normal human kidney with anti-sortilin and anti-M6PR showed that sortilin and M6PR were expressed in the endothelium of smaller and larger vessels. Uptake studies in cultured glomerular endothelial cells of α-Gal A labeled with fluorescence and 125I showed by inhibition with RAP and M6P that sortilin and M6PR mediated uptake of α-Gal A. Biacore studies revealed that α-Gal A binds to human M6PR with very high affinity, but M6PR also binds to sortilin in a way that prevents α-Gal A binding to sortilin. Taken together, our data provide evidence that sortilin is a new α-Gal A receptor expressed in renal endothelial cells and that this receptor together with the M6PR is able to internalize circulating α-Gal A during enzyme replacement therapy in patients with Fabry disease

Receptor-Mediated Endocytosis of α-Galactosidase A in Human Podocytes in Fabry Disease

Injury to the glomerular podocyte is a key mechanism in human glomerular disease and podocyte repair is an important therapeutic target. In Fabry disease, podocyte injury is caused by the intracellular accumulation of globotriaosylceramide. This study identifies in the human podocyte three endocytic receptors, mannose 6-phosphate/insulin-like growth II receptor, megalin, and sortilin and demonstrates their drug delivery capabilities for enzyme replacement therapy. Sortilin, a novel α-galactosidase A binding protein, reveals a predominant intracellular expression but also surface expression in the podocyte. The present study provides the rationale for the renal effect of treatment with α-galactosidase A and identifies potential pathways for future non-carbohydrate based drug delivery to the kidney podocyte and other potential affected organs

Early start and stop of biologics: has the time come?

Despite considerable advances in the management of rheumatoid arthritis, results are still not satisfactory for all patients. The treatment goal in rheumatoid arthritis is remission, and there currently are numerous conventional and biological medications available to reach this aim. There are also different treatment strategies but with only limited comparative evidence about their efficacies. More patients now achieve remission while on treatment, but it remains elusive in the majority of patients. Treatment-free remission, the ultimate goal of therapy, is only achieved in very few patients; even when this happens, it is most likely due to the natural course of the disease rather than to any specific therapies. Modern treatment is based on the initiation of aggressive therapy as soon as the diagnosis is established, and on modifying or intensifying therapy guided by frequent assessment of disease activity. In this commentary we will discuss the current treatment paradigm as well as the possibility of an induction-maintenance regimen with biological disease-modifying antirheumatic drugs in early rheumatoid arthriti

Low level of physical activity in women with rheumatoid arthritis is associated with cardiovascular risk factors but not with body fat mass - a cross sectional study

<p>Abstract</p> <p>Background</p> <p>As many patients with rheumatoid arthritis (RA) have increased fat mass (FM) and increased frequency of cardiovascular diseases we evaluated if total physical activity (MET-hours) had impact on body composition and cardiovascular risk factors in women with RA.</p> <p>Methods</p> <p>Sixty-one out-ward RA women, 60.8 (57.3-64.4) years, answered a self-administered questionnaire, to estimate total daily physical activity during the previous year. Physical activity level was given as metabolic equivalents (MET) × h/day. Diet content was assessed by a food frequency questionnaire and body composition by whole-body dual-energy X-ray absorptiometry. Blood lipids and antibodies against phosphorylcholine (anti-PC) were determined.</p> <p>Results</p> <p>Forty-one percent of the women had BMI > 25, 6% were centrally obese and 80% had FM% > 30%. The median (IQR) total physical activity was 40.0 (37.4-47.7), i.e. the same activity level as healthy Swedish women in the same age. Total physical activity did not significantly correlate with disease activity, BMI or FM%. Disease activity, BMI and FM% did not differ between those in the lowest quartile of total physical activity and those in the highest quartile. However, the women in the lowest quartile of physical activity had lower HDL (p = 0.05), Apo A1 (p = 0.005) and atheroprotective natural anti-PC (p = 0.016) and higher levels of insulin (p = 0.05) and higher frequency of insulin resistance than those in the highest quartile. Women in the lowest quartile consumed larger quantities of saturated fatty acids than those in the highest quartile (p = 0.042), which was associated with high oxidized low-density lipoprotein (oxLDL).</p> <p>Conclusion</p> <p>This cross sectional study demonstrated that RA women with fairly low disease activity, good functional capacity, high FM and high frequency of central obesity had the same total physical activity level as healthy Swedish women in the same age. The amount of total physical activity was not associated with functional capacity or body composition. However, low total physical activity was associated with dyslipidemia, insulin resistance, low levels of atheroprotective anti-PC and consumption of saturated fatty acids, which is of interest in the context of increased frequency of cardiovascular disease in RA.</p

Search for rare quark-annihilation decays, B --> Ds(*) Phi

We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and u-bar quarks in the B- meson. Our results are based on 234 million Upsilon(4S) --> B Bbar decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions BF(B- --> Ds- Phi) Ds*- Phi)<1.2x10^(-5). These results are consistent with Standard Model expectations.Comment: 8 pages, 3 postscript figues, submitted to Phys. Rev. D (Rapid Communications

Search for Charged Higgs Bosons in e+e- Collisions at \sqrt{s} = 189 GeV

A search for pair-produced charged Higgs bosons is performed with the L3 detector at LEP using data collected at a centre-of-mass energy of 188.6 GeV, corresponding to an integrated luminosity of 176.4 pb^-1. Higgs decays into a charm and a strange quark or into a tau lepton and its associated neutrino are considered. The observed events are consistent with the expectations from Standard Model background processes. A lower limit of 65.5 GeV on the charged Higgs mass is derived at 95 % confidence level, independent of the decay branching ratio Br(H^{+/-} -> tau nu)

Observation and study of baryonic B decays: B -> D(*) p pbar, D(*) p pbar pi, and D(*) p pbar pi pi

We present a study of ten B-meson decays to a D(*), a proton-antiproton pair, and a system of up to two pions using BaBar's data set of 455x10^6 BBbar pairs. Four of the modes (B0bar -> D0 p anti-p, B0bar -> D*0 p anti-p, B0bar -> D+ p anti-p pi-, B0bar -> D*+ p anti-p pi-) are studied with improved statistics compared to previous measurements; six of the modes (B- -> D0 p anti-p pi-, B- -> D*0 p anti-p pi-, B0bar -> D0 p anti-p pi- pi+, B0bar -> D*0 p anti-p pi- pi+, B- -> D+ p anti-p pi- pi-, B- -> D*+ p anti-p pi- pi-) are first observations. The branching fractions for 3- and 5-body decays are suppressed compared to 4-body decays. Kinematic distributions for 3-body decays show non-overlapping threshold enhancements in m(p anti-p) and m(D(*)0 p) in the Dalitz plots. For 4-body decays, m(p pi-) mass projections show a narrow peak with mass and full width of (1497.4 +- 3.0 +- 0.9) MeV/c2, and (47 +- 12 +- 4) MeV/c2, respectively, where the first (second) errors are statistical (systematic). For 5-body decays, mass projections are similar to phase space expectations. All results are preliminary.Comment: 28 pages, 90 postscript figures, submitted to LP0