Identification of Critical Amino Acids in an Immunodominant IgE Epitope of Pen c 13, a Major Allergen from Penicillium citrinum

Background: Pen c 13, identified as a 33-kDa alkaline serine protease, is a major allergen secreted by Penicillium citrinum. Detailed knowledge about the epitopes responsible for IgE binding would help inform the diagnosis/prognosis of fungal allergy and facilitate the rational design of hypoallergenic candidate vaccines. The goal of the present study was to characterize the IgE epitopes of Pen c 13. Methodology/Principal Findings: Serum samples were collected from 10 patients with mold allergy and positive Pen c 13 skin test results. IgE-binding epitopes on rPen c 13 were mapped using an enzymatic digestion and chemical cleavage method, followed by dot-blotting and mass spectrometry. A B-cell epitope-predicting server and molecular modeling were used to predict the residues most likely involved in IgE binding. Theoretically predicted IgE-binding regions were further confirmed by site-directed mutagenesis assays. At least twelve different IgE-binding epitopes located throughout Pen c 13 were identified. Of these, peptides S16 (A 148 –E 166) and S22 (A 243 –K 274) were recognized by sera from 90 % and 100 % of the patients tested, and were further confirmed by inhibition assays. Peptide S22 was selected for further analysis of IgE-binding ability. The results of serum screening showed that the majority of IgE-binding ability resided in the C-terminus. One Pen c 13 mutant, G270A (T 261 –K 274), exhibited clearly enhanced IgE reactivity, whereas another, K274A, exhibited dramatically reduced IgE reactivity

An update on molecular cat allergens: Fel d 1 and what else? Chapter 1: Fel d 1, the major cat allergen

Background: Cats are the major source of indoor inhalant allergens after house dust mites. The global incidence of cat allergies is rising sharply, posing a major public health problem. Ten cat allergens have been identified. The major allergen responsible for symptoms is Fel d 1, a secretoglobin and not a lipocalin, making the cat a special case among mammals. Main body: Given its clinical predominance, it is essential to have a good knowledge of this allergenic fraction, including its basic structure, to understand the new exciting diagnostic and therapeutic applications currently in development. The recent arrival of the component-resolved diagnosis, which uses molecular allergens, represents a unique opportunity to improve our understanding of the disease. Recombinant Fel d 1 is now available for in vitro diagnosis by the anti-Fel d 1 specific IgE assay. The first part of the review will seek to describe the recent advances related to Fel d 1 in terms of positive diagnosis and assessment of disease severity. In daily practice, anti-Fel d 1 IgE tend to replace those directed against the overall extract but is this attitude justified? We will look at the most recent arguments to try to answer this question. In parallel, a second revolution is taking place thanks to molecular engineering, which has allowed the development of various forms of recombinant Fel d 1 and which seeks to modify the immunomodulatory properties of the molecule and thus the clinical history of the disease via various modalities of anti-Fel d 1-specific immunotherapy. We will endeavor to give a clear and practical overview of all these trends

Synthesis of Niti Based Nanocomposites Reinforced by Ha Addition

NiTi alloy is well known for its unique properties, such as good ductility at room temperature, good corrosion resistance and also thermal shape memory effects. On the other hand hydroxyapatite has a combination of desirable properties, such as low density and excellent compatibility with the bone which used as ceramic reinforced phases can change the properties and thermal stability of the NiTi alloy. In this study, the NiTi alloy matrix shape memory composite reinforced by hydroxyapatite particles was successfully fabricated using mechanical alloying and powder metallurgical process. The structural evaluation of milled and heat treated powders was studied by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The differential scanning calorimetry was used to measure the phase transformation temperatures. The porosity, Vickers’ hardness and corrosion resistance of the TiNi-HA composites were investigated. The results show that the increase of the weight ratio of hydroxyapatite causes increase the porosity and decrease the corrosion resistance. The fabricated NiTi alloy matrix composite possesses lower density and higher Vickers’ hardness as the pure NiTi shape memory alloy, yet still exhibiting the shape memory effect

Rhinovirus-induced VP1-specific Antibodies are Group-specific and Associated With Severity of Respiratory Symptoms.

Rhinoviruses (RVs) are a major cause of common colds and induce exacerbations of asthma and chronic inflammatory lung diseases.We expressed and purified recombinant RV coat proteins VP1-4, non-structural proteins as well as N-terminal fragments of VP1 from four RV strains (RV14, 16, 89, C) covering the three known RV groups (RV-A, RV-B and RV-C) and measured specific IgG-subclass-, IgA- and IgM-responses by ELISA in subjects with different severities of asthma or without asthma before and after experimental infection with RV16.Before infection subjects showed IgG1 > IgA > IgM > IgG3 cross-reactivity with N-terminal fragments from the representative VP1 proteins of the three RV groups. Antibody levels were higher in the asthmatic group as compared to the non-asthmatic subjects. Six weeks after infection with RV16, IgG1 antibodies showed a group-specific increase towards the N-terminal VP1 fragment, but not towards other capsid and non-structural proteins, which was highest in subjects with severe upper and lower respiratory symptoms.Our results demonstrate that increases of antibodies towards the VP1 N-terminus are group-specific and associated with severity of respiratory symptoms and suggest that it may be possible to develop serological tests for identifying causative RV groups

Nanokompozyty tytanowe do zastosowań w medycynie

Titanium and titanium alloys possess favorable properties, such as relatively low modulus, low density, high strength. Apart from that, these alloys are generally regarded to have good biocompatibility and high corrosion resistance, but cannot directly bond to the bone. In addition, metal implants may loose and even separate from surrounding tissues during implantation. One of the methods that allow the change of biological properties of Ti alloys is to produce a composite, which will exhibit the favorable mechanical properties of titanium and excellent biocompatibility and bioactivity of ceramic. Recently, at Poznan University of Technology, mechanical alloying method (MA) and powder metallurgy process for the fabrication of novel titanium-ceramic nanocomposites with a unique microstructure has been developed. This process permits the control of microstructural properties such as the size of pore openings, surfaces properties, and the nature of the base metal/alloy. In our work, the structure, mechanical, corrosion properties and biocompatibility of titanium-ceramic nanocomposites were studied. For example, the Ti-HA nanocomposites mainly consist of different apatite or calcium particles, respectively, reinforced with titanium matrix. The existence of Ti can promote decomposition of HA, however no reactions form between HA and Ti. Different phase constitutions have significant influence on the mechanical and corrosion properties of sintered materials. The biocompatibility was investigated studying the behaviour of Normal Human Osteoblast (NHOst) cells, as well. Ti-ceramic nanocomposites posses better mechanical and corrosion properties than microcrystalline titanium. For this reason, they are promising biomaterial for use as medical implants.Tytan i stopy tytanu charakteryzują szeregiem korzystnych własności takich jak niski moduł sprężystości, mała gęstość, wysoka wytrzymałość. Powszechnie uważa się, że stopy te maja dobrą biokompatybilność i odporność korozyjną lecz nie mogą bezpośrednio łączyć się z kością. Jednakże, implanty metalowe w czasie użytkowania mogą się obluzowywać a nawet oddzielać od otaczającej tkanki. Jedną z metod, pozwalającą na zmianę własności biologicznych stopów tytanu, jest wytwarzanie kompozytów, które będą łączyć korzystne własności wytrzymałościowe tytanu z doskonałą biokompatybilnością i bioaktywnością ceramiki. Ostatnio, w Instytucie Inżynierii Materiałowej Politechniki Poznańskiej opracowano technologię wytwarzania nowych nanokompozytów tytanowo-ceramicznych metodą mechanicznej syntezy i metalurgii proszków. Procesy te umożliwiają kontrolę własności mikrostruktury takich jak wielkość por i własności powierzchni. W niniejszej pracy zbadano własności strukturalne, mechaniczne, korozyjne i biokompatybilność kompozytów tytanowo-ceramicznych. Przykładowo, nanokompozyty typu Ti-HA zbudowane są głównie z cząstek różnego rodzaju apatytów i wapnia rozłożonych w osnowie tytanowej. Obecność tytanu może powodować rozkład HA, jednakże reakcja pomiędzy HA i Ti nie jest obserwowana. Różna budowa fazowa syntetyzowanych materiałów ma znaczący wpływ na ich własności mechaniczne i odporność korozyjną. Zbadano również biokompatybilność kompozytów w hodowli komórek ludzkich osteoblastów. Wytworzone nanokompozyty tytanowo-ceramiczne posiadają lepsze własności mechaniczne i korozyjne w porównaniu do mikrokrystalicznego tytanu. Z tego względu mogą stać się perspektywicznymi biomateriałami do zastosowań na implanty medyczne

Synthesis of Niti Based Nanocomposites Reinforced by Ha Addition

NiTi alloy is well known for its unique properties, such as good ductility at room temperature, good corrosion resistance and also thermal shape memory effects. On the other hand hydroxyapatite has a combination of desirable properties, such as low density and excellent compatibility with the bone which used as ceramic reinforced phases can change the properties and thermal stability of the NiTi alloy

Metallic nanomaterials for advanced applications

Artykuł jest przeglądem badań prowadzonych w Instytucie Inżynierii Materiałowej Politechniki Poznańskiej nad otrzymywaniem materiałów metalicznych z nanostrukturą. Materiały te otrzymywane są metodą mechanicznej syntezy a następnie konsolidowane za pomocą technologii metalurgii proszków. Przykładami otrzymanych nanomateriałów są: nanokompozyt tytan - hydroxyapatyt, nanokrystaliczna bez niklowa stal nierdzewna, mające zastosowanie jako biomateriały, oraz dwusiarczek molibdenu (MoS2) w postaci nanocząstek mający zastosowanie w materiałach inżynierskich. Wynik badań pokazują, iż materiały posiadające nanostrukturę wykazują lepsze właściwości w porównaniu do materiałów tradycyjnych.This paper reviews research at the Institute of Materials Science and Engineering, Poznań University of Technology, on the synthesis of nanoscale metallic materials. These materials were prepared by the combination of mechanical alloying and powder metallurgical process. Examples of the materials include a titanium-hydroxyapatite nanocomposite, a nanocrystalline nickel-free stainless steels, both for biomedical applications, and molybdenum disulfide (MoS2) nanoparticles for engineering applications. The results show an enhancement of properties due to the nanoscale structures in bulk consolidated materials