Proinflammatory T helper type 17 cells are effective B-cell helpers

T helper type 17 (TH17) cells are highly proinflammatory effector T cells that are characterized by the production of high amounts of IL-17A, IL-17F, IL-21, and IL-22. Furthermore, TH17 cells have been associated with a number of autoimmune diseases. However, it is not clear whether TH17 cells can also serve as effective helper cells. Here we show that TH17 cells can function as B-cell helpers in that they not only induce a strong proliferative response of B cells in vitro but also trigger antibody production with class switch recombination in vivo. Transfer of TH17 cells into WT or T-cell receptor α–deficient mice, which lack endogenous T cells, induces a pronounced antibody response with preferential isotype class switching to IgG1, IgG2a, IgG2b, and IgG3, as well as the formation of germinal centers. Conversely, blockade of IL-17 signaling results in a significant reduction in both number and size of germinal centers. Whereas IL-21 is known to help B cells, IL-17 on its own drives B cells to undergo preferential isotype class switching to IgG2a and IgG3 subtypes. These observations provide insights into the unappreciated role of TH17 cells and their signature cytokines in mediating B-cell differentiation and class switch recombination.     

Objectively measured physical activity of USA adults by sex, age, and racial/ethnic groups: a cross-sectional study

Background  

Accelerometers were incorporated in the 2003–2004 National Health and Nutritional Examination Survey (NHANES) study cycle for objective assessment of physical activity. This is the first time that objective physical activity data are available on a nationally representative sample of U.S. residents. The use of accelerometers allows researchers to measure total physical activity, including light intensity and unstructured activities, which may be a better predictor of health outcomes than structured activity alone. The aim of this study was to examine objectively determined physical activity levels by sex, age and racial/ethnic groups in a national sample of U.S. adults.     

Reasons for non-adherence to vaccination at mother and child care clinics (MCCs) in Lambaréné, Gabon

The aim of this paper is to explore attitudes of mothers towards childhood vaccinations and reasons for non-attendance and non-adherence to mother–child clinics (MCCs). Forty in-depth interviews with mothers of children under 5 years of age revealed positive attitudes towards vaccination that seem at odds with the region's observed low vaccination coverage. Important reasons for MCC non-attendance included distance to the MCC, transport costs, negative experiences at MCCs (such as interactions with unfriendly staff) and mothers’ feeling of shame provoked by different, often poverty-associated reasons such as attending the clinic with a dirty or poorly clothed child.     

Comparison of three-year clinical outcome of sirolimus- and paclitaxel-eluting stents versus bare metal stents in patients with ST-segment elevation myocardial infarction (from the RESEARCH and T-SEARCH Registries)

Sirolimus-eluting stents (SESs) recently proved to be superior to bare metal stents (BMSs) in decreasing the need for repeat revascularization in patients with ST-segment elevation myocardial infarction (STEMI) at 1 year. Whether this also holds for paclitaxel-eluting stents (PESs) is currently unclear and the long-term relatively efficacy of the 2 drug-eluting stents is currently unknown. We investigated the 3-year efficacy of SESs and PESs versus BMSs in patients with STEMI. Primary angioplasty was performed in a consecutive group of 505 patients (BMSs in 183, SESs in 186, PESs in 136). At 3 years, the cumulative mortality rate was comparable in the 3 groups: 13.3% in the BMS group, 11.5% in the SES group, and 12.4% in the PES group (nonsignificant for all). The rate of target vessel revascularization (TVR) was 12.0% in the BMS group compared with 8.0% and 7.7% in the SES and PES groups, respectively (p = 0.12 for BMS vs SES, 0.30 for BMS vs PES, 0.62 for SES vs PES). The cumulative incidence of death, MI, or TVR was 25.5% in the BMS group compared with 17.9% and 20.6% in the SES and PES groups, respectively (p = 0.06 for BMS vs SES, 0.32 for BMS vs PES, 0.45 for SES vs PES). Angiographic stent thrombosis occurred in 2.4% of all patients (BMS 1.6%, SES 2.7%, PES 2.9%). In conclusion, in this relatively small consecutive patient cohort, the use of SESs and PESs was no longer associated with significantly lower rates of TVR and major adverse cardiace events in patients with STEMI after 3 years of follow-up. A high frequency of stent thrombosis was observed in the 2 drug-eluting stent groups.     

Generation of activation-specific human anti-alphaMbeta2 single-chain antibodies as potential diagnostic tools and therapeutic agents

The leukocyte integrin Mac-1 (alpha(M)beta(2)) plays a pivotal role in inflammation and host defense. Upon leukocyte activation, Mac-1 undergoes a conformational change exposing interaction sites for multiple ligands. We aimed to generate single-chain antibodies (scFv's) directed against activation-specific Mac-1 ligand-binding sites. Using human scFv phage libraries, we developed subtractive strategies with depletion of phages binding to nonactivated Mac-1 and selection of phages binding to activated Mac-1, using monocytes as well as CHO cells transfected with native or mutated, activated Mac-1. Three scFv clones demonstrated exclusive binding to activated Mac-1. Mac-1 binding of the ligands fibrinogen, heparin, and ICAM-1, but not C3bi, was inhibited. Using alanine substitutions, the paratope was identified within the heavy chain HCDR3s of the scFv's. The epitope was localized to Lys(245)-Arg(261) of the alpha(M) I-domain. In a pilot study with septicemic patients, we provide initial support for the use of these scFv's as markers of monocyte activation and as potential diagnostic tools. Potential therapeutic use was tested in adhesion assays under static and flow conditions demonstrating the selective blockade of activated monocytes only. Furthermore, scFv HCDR3-derived peptides retain selectivity for the activated integrin, providing a unique template for the potential development of inhibitors that are specific for the activated Mac-1.     

Selegiline reduces cisplatin-induced neuronal death in neuroblastoma cells

Long-term administration of the monoamine oxidase (MAO)-B inhibitor selegiline may reduce neuronal death based on preclinical findings and reduce progression of chronic neurodegeneration due to outcomes of long-term clinical trials in patients with Parkinson's disease. Additional modes of action of this compound are immune system modulating and neurotrophic properties. We investigated the impact of simultaneous selegiline and cisplatin administration on the degree of cisplatin-induced cell death in SH-SY 5Y human neuroblastoma cells. We found a significantly reduced cell death rate after 50 and 74 hours after 2 hours lasting cisplatin exposure of SH-SY 5Y cells with additional selegiline treatment in comparison with cultures without selegiline. No previous incubation of cell cultures with selegiline was necessary to achieve this neuroprotective effect. We suggest that the neuroprotective effect of selegiline is predominantly associated with neurotrophic actions but not MAO-B inhibition, because SH-SY 5Y human neuroblastoma cells only contain MAO-A. Clinically, our findings support an early start of long-term treatment with selegiline in view of the various neurotoxin hypotheses and mechanisms of neuronal death in chronic neurodegenerative disorders.