The N-terminal region of the human papillomavirus L2 protein contains overlapping binding sites for neutralizing, cross-neutralizing and non-neutralizing antibodies

The N-terminal region of the human papillomavirus (HPV) L2 protein has been shown to contain immune epitopes able to induce the production of neutralizing and cross-neutralizing antibodies (Gambhira et al., 2007; Kawana et al., 1999). Using bacterial thioredoxin as a scaffold, we managed to enhance the immunogenicity of putative L2 neutralizing epitopes, but only a minor fraction of the resulting immune responses was found to be neutralizing (Rubio et al., 2009). To determine the recognition patterns for non-neutralizing, neutralizing and cross-neutralizing antibodies, we isolated and characterized a panel of 46 monoclonal antibodies directed against different HPV16 L2 epitopes. Four of such antibodies proved to be neutralizing, and two of them, both targeting the amino acid (aa) 20-38 region of L2, were found to cross-neutralize a broad range of papillomaviruses. The epitopes recognized by neutralizing and cross-neutralizing antibodies were mapped at high resolution and were found to be characterized by distinct recognition patterns. Even in the case of the L2 20-38 epitope, cross-neutralization of HPV31 pseudovirions proved to be extremely inefficient, and this was found to be primarily due to the lack of a proline residue at position 30. HPV16 specific amino acids in this region also appear to be responsible for the lack of cross-neutralizing activity, thus suggesting a potential immune escape mechanism. For the aa 71-80 region, instead, the data indicate that restriction of neutralization to HPV16 is due to sequence (or structural) differences laying outside of the epitope. Besides providing new insights on the molecular bases of L2-mediated immune reactivity, the present data may pave the way to novel vaccination approaches specifically evoking cross-neutralizing antibody responses.     

Hard and fast rules about the body: contributions of the action stream to judging body space

Analogously to the visual system, somatosensory processing may be segregated into two streams, with the body constituting either part of the action system or a perceptual object. Experimental studies with participants free from neurological disease which test this hypothesis are rare, however. The present study explored the contributions of the two putative streams to a task that requires participants to estimate the spatial properties of their own body. Two manipulations from the visuospatial literature were included. First, participants were required to point either backward towards pre-defined landmarks on their own body (egocentric reference frame) or to a forward projection of their own body (allocentric representation). Second, a manipulation of movement mode was included, requiring participants to perform pointing movements either immediately, or after a fixed delay, following instruction. Results show that accessing an allocentric representation of one’s own body results in performance changes. Specifically, the spatial bias shown to exist for body space when pointing backward at one’s own body disappears when participants are requested to mentally project their body to a pre-defined location in front space. Conversely, delayed execution of pointing movements does not result in performance changes. Altogether, these findings provide support for a constrained dual stream hypothesis of somatosensory processing and are the first to show similarities in the processing of body space and peripersonal space.     

Electrospun Hydroxyapatite-Functionalized PLLA Scaffold: Potential Applications in Sternal Bone Healing

Sternal synthesis after median sternotomy, a conventional access practice in thoracic and cardiac surgery, is at the basis of severe complications, often impairing the clinical outcome of surgical interventions. In this work, we propose the use of an acellular biomaterial scaffold, to be interposed across the fracture rime during closure operations, directly exposing the biomaterial to bone marrow, in order to expedite healing process. A rabbit model of median sternotomy was performed and an electrospun scaffold composed of a hydroxyapatite-loaded absorbable biopolymer (poly-L: -lactide), shaped into a fibrillar structure, was used. CT follow-up confirmed a complete healing in the scaffold-treated group 1 week before the control. Histological evaluation demonstrated presence of newly formed bone trabeculae among scaffold fibers showing a higher degree of maturity with respect to the control untreated group. The proposed approach is able to both guide a more rapid healing and modulate inflammatory response across the wound site, resulting in improved healing and tissue remodeling with respect to conventional closure technique.     

Interleukins, from 1 to 37, and interferon-γ: receptors, functions, and roles in diseases

Advancing our understanding of mechanisms of immune regulation in allergy, asthma, autoimmune diseases, tumor development, organ transplantation, and chronic infections could lead to effective and targeted therapies. Subsets of immune and inflammatory cells interact via ILs and IFNs; reciprocal regulation and counter balance among T(h) and regulatory T cells, as well as subsets of B cells, offer opportunities for immune interventions. Here, we review current knowledge about ILs 1 to 37 and IFN-γ. Our understanding of the effects of ILs has greatly increased since the discoveries of monocyte IL (called IL-1) and lymphocyte IL (called IL-2); more than 40 cytokines are now designated as ILs. Studies of transgenic or knockout mice with altered expression of these cytokines or their receptors and analyses of mutations and polymorphisms in human genes that encode these products have provided important information about IL and IFN functions. We discuss their signaling pathways, cellular sources, targets, roles in immune regulation and cellular networks, roles in allergy and asthma, and roles in defense against infections.     

Free Fatty Acids Link Metabolism and Regulation of the Insulin-Sensitizing Fibroblast Growth Factor-21

OBJECTIVE

Fibroblast growth factor (FGF)-21 improves insulin sensitivity and lipid metabolism in obese or diabetic animal models, while human studies revealed increased FGF-21 levels in obesity and type 2 diabetes. Given that FGF-21 has been suggested to be a peroxisome proliferator–activator receptor (PPAR) α–dependent regulator of fasting metabolism, we hypothesized that free fatty acids (FFAs), natural agonists of PPARα, might modify FGF-21 levels.

RESEARCH DESIGN AND METHODS

The effect of fatty acids on FGF-21 was investigated in vitro in HepG2 cells. Within a randomized controlled trial, the effects of elevated FFAs were studied in 21 healthy subjects (13 women and 8 men). Within a clinical trial including 17 individuals, the effect of insulin was analyzed using an hyperinsulinemic-euglycemic clamp and the effect of PPARγ activation was studied subsequently in a rosiglitazone treatment trial over 8 weeks.

RESULTS

Oleate and linoleate increased FGF-21 expression and secretion in a PPARα-dependent fashion, as demonstrated by small-interfering RNA–induced PPARα knockdown, while palmitate had no effect. In vivo, lipid infusion induced an increase of circulating FGF-21 in humans, and a strong correlation between the change in FGF-21 levels and the change in FFAs was observed. An artificial hyperinsulinemia, which was induced to delineate the potential interaction between elevated FFAs and hyperinsulinemia, revealed that hyperinsulinemia also increased FGF-21 levels in vivo, while rosiglitazone treatment had no effect.

CONCLUSIONS

The results presented here offer a mechanism explaining the induction of the metabolic regulator FGF-21 in the fasting situation but also in type 2 diabetes and obesity.Fibroblast growth factor (FGF)-21 is a recently discovered metabolic regulator of fasting metabolism. FGF-21 activates glucose uptake in adipocytes, protects animals from diet-induced obesity when overexpressed in transgenic mice, and lowers blood glucose and triglyceride levels when administered to diabetic rodents (1–3). Comparably, glucose- and triglyceride-lowering effects were found in diabetic rhesus monkeys during chronic FGF-21 treatment over a period of 6 weeks (4). Therefore, FGF-21 was assumed to be a novel target with potential antidiabetic properties, which might be useful in the treatment of hyperglycemia, insulin resistance, and hyperlipidemia.However, human data did not directly support these assumptions, since increased serum FGF-21 levels were found in obese individuals, patients with type 2 diabetes, and subjects with metabolic syndrome (5,6). In addition FGF-21 levels correlated positively not only with adiposity but also with fasting insulin and triacylglycerols (5). A recent study (3) reported a significant increase of FGF-21 levels during prolonged fasting. This process appeared to be peroxisome proliferator–activator receptor (PPAR) α–dependent (2,3), although exact mechanisms leading to fasting-induced FGF-21 elevations are yet unknown.Various data support that metabolic parameters themselves can modulate the circulating levels of hormones and adipokines (7–10). Thus, free fatty acids (FFAs) activate PPARs and were found to be elevated in fasting conditions. We therefore speculated that FFAs themselves might regulate FGF-21. This hypothesis is supported by recent data demonstrating that FGF-21 levels are positively associated with FFAs (11) and triacylglycerols (3) in a cross-sectional study population of nondiabetic individuals. Although the direction of that relation is unclear in a cross-sectional study, it offers a potential mechanism linking starvation to the increased levels of FGF-21. We therefore investigated the effect of fatty acids on FGF-21 secretion in HepG2 cells in vitro. Based on these in vitro data, we performed a randomized controlled trial to explore whether an increase in circulating FFAs and triacylglycerols modifies FGF-21 levels in humans. Since an increase of FFAs is known to induce insulin resistance and hyperinsulinemia, the effect of insulin on FGF-21 was additionally investigated by performing a hyperinsulinemic-euglycemic clamp at baseline of a noncontrolled, rosiglitazone intervention trial. As some recent animal data (12) also suggested a PPARγ-dependent regulation of FGF-21, we finally evaluated the effect of the PPARγ agonist, rosiglitazone, in that human trial.     

Effect of low-level laser therapy after implantation of poly-<Emphasis Type="SmallCaps">L</Emphasis>-lactic/polyglycolic acid in the femurs of rats

This study evaluated the use of red and infrared lasers on tissue surrounding the femurs of 60 rats randomly divided into three groups after implantation of bioabsorbable plates. The control group were not subjected to laser irradiation; group A was treated with red laser [indium–gallium–aluminum–phosphide (InGaAlP) laser, wavelength 685 nm, 35 mW, continuous wave (CW), Ø?=?0.06 cm, 2.23 min], and group B was subjected to infrared laser [gallium–aluminum–arsenium (GaAlAs) laser, wavelength 830 nm, 50 mw, CW, Ø?=?0.06 cm, 1.41 min], both at 10 J/cm². Samples were stained with hematoxylin and eosin (H&;E) and examined microscopically. Results showed that the laser irradiation had had a positive photobiomodulation effect on inflammation, confirmed by a better histologic pattern than that of the control group at 3 days and 7 days. Semiquantitative analysis revealed that groups A and B had a histologic score significantly greater than that of the control group at 3 days. At 21 days, histomorphometric analysis revealed a more intense inflammation in the red laser group than in the other groups. We concluded that low-level laser therapy (LLLT) has positive effects on the photobiomodulation of inflammation in the tissues surrounding the poly-L-lactic/polyglycolic acid (PLLA/PGA) bioabsorbable plate. It stimulated vascularization, fibroblast proliferation, and collagen deposition.