bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vitro Experiments Demonstrate that Monocytes and Dendritic Cells are Rendered Apoptotic by Extracorporeal Photochemotherapy, but Exhibit Unaffected Surviving and Maturing Capacity after 30 Gy Gamma Irradiation
Authors: Rao V. , Saunes M. , Jørstad S. , Moen T. 
Published: August 2010

AbstractExtracorporeal photochemotherapy (ECP) has been shown to induce apoptosis in lymphocytes. Until recently the prevailing opinion has been that the monocytes were mainly not affected by this treatment. This study has investigated the effect of ECP and gamma irradiation on monocytes and immature dendritic cells (DC) in vitro and followed the ability of the cells to differentiate and survive post treatment. ECP induced apoptosis in lymphocytes, monocytes and immature DC within 72 h following treatment, in contrast to 30 Gy gamma irradiation, which seemed mainly to affect lymphocytes. The minority of the surviving ECP‐treated monocytes presented a reduced ability to differentiate into immature DC within this time frame. We also demonstrated that immature DC after ECP‐treatment lost their normal ability to mature on stimulation with lipopolysaccharide. As monocytes and immature DC seem to have a reduced ability to differentiate after ECP‐treatment, it is suggested that the therapeutic effect of ECP is caused by in vivo effects of reinfused apoptotic cells, rather than by infusion of monocytes induced to differentiate into immature DC.
Naive Human T‐Cells become Non‐Responsive towards Anti‐TNFα (Infliximab) Treatment In vitro if Co‐Stimulated through CD28
Authors: Gunnlaugsdottir B. , Skaftadottir I. , Ludviksson B. R. 
Published: August 2010

AbstractTumour necrosis factor α (TNFα) inhibitors are widely used successfully as immunomodulatory agents in various autoimmune diseases. They primarily target the direct pro‐inflammatory effect of TNFα. They have also been found to be critical for T‐cell viability and activation. In this study we evaluated the effect of infliximab treatment under different in vitro stimulatory conditions of naive human cord blood T‐cells and adult peripheral blood mononuclear cells (PBMC). PBMC and negatively selected cord blood naive human T‐cells were stimulated with αCD3 with or without αCD28 co‐stimulation. The role of in vitro infliximab treatment was evaluated in relation to transforming growth factor‐β1 (TGF‐β1) under the above different stimulatory conditions. Anti‐TNFα treatment with infliximab significantly suppressed proliferation of adult and cord blood T‐cells (P < 0.013) during suboptimal stimulatory conditions. Infliximab prevented division of naive CD4+ and CD8+ T‐cells and consequently also activation induced cell death, which was induced after three cell divisions. Interleukin (IL)‐2 secretion was significantly decreased during infliximab treatment of suboptimally stimulated T‐cells (P < 0.05) while TGF‐β1 levels were unchanged. Strikingly, the anti‐proliferative effect of infliximab was overcome by the administration of anti‐TGF‐β1 or by the addition of exogenous IL‐2. Interestingly, CD28 mediated co‐stimulation restored the proliferative response in a dose–responsive manner during infliximab treatment. Finally, exogenous TNFα administration during suboptimal stimulation reduced the inhibitory effect of TGF‐β1 upon proliferation (P < 0.03). These results demonstrate that anti‐TNFα treatment is primarily working upon T cells under low stimulatory conditions and probably through TGF‐β1.
The Impact of Hormone Replacement Therapy on Humoral and Cell‐mediated Immune Responses In Vivo in Post‐menopausal Women with Rheumatoid Arthritis
Authors: Forsblad d′Elia H. , Carlsten H. 
Published: August 2010

AbstractIt is well known that oestrogen has immunomodulatory properties. We have previously shown disease ameliorating effects of hormone replacement therapy (HRT) in post‐menopausal women with rheumatoid arthritis (RA). The aim of this study was to investigate the effects of HRT and the patients inflammatory state on humoral and cell‐mediated immune responses. Eighty‐eight post‐menopausal RA women were allocated to receive HRT (oestradiol and noretisterone acetate), vitamin D3 and calcium or vitamin D3 and calcium alone in a 2‐year randomized controlled trial. Immunoglobulins (IgM, IgG and IgA) in serum were measured by nephelometry and rheumatoid factor (RF) concentration by enzyme‐linked immunosorbent assay. Immunization with influenza vaccine was performed to quantitate humoral response to recall antigen and tuberculin skin test with purified protein derivative (PPD) to test T‐cell‐mediated immune response. These immune related measures were correlated with demographic and disease‐related variables. HRT during 2 years did not alter concentrations of Ig, RF, IgM response to influenza vaccine or the PPD reaction. The increase in IgM against influenza vaccine was significantly positively correlated with signs of disease activity; C‐reactive protein, disease activity score 28 and inversely with haemoglobin. In contrast, PPD reactivity was inversely associated with disease activity. In conclusion, long‐term HRT in RA does not influence Ig or autoantibody concentrations in serum and has no significant impact on humoral and cell‐mediated immune responses to recall antigens. Interestingly, high disease activity was associated to increased humoral but decreased cell‐mediated immune responses irrespectively of hormone treatment.
Influence of L‐naphthylalanine in position 3 of AVP and its analogues on their pharmacological properties
Authors: LAMMEK B. , CZAJA M. , DERDOWSKA I. , REKOWSKI P. , TRZECIAK H.I. , SIKORA P. , SZKRÓBKA W. , STOJKO R. , KUPRYSZEWSKI G. 
Published: August 2010

We describe the synthesis and pharmacological properties of two series of analogues: one which consists of three peptides having L‐1‐naphthylalanine in position 3 and the second composed of analogues substituted in position 3 with L‐2‐naphthylalanine. All peptides were tested in bioassays for pressor and antidiuretic activities. We also checked the uterotonic activityin vitro. We observed that the activity of counterparts in both series is, in two cases, strikingly different.One of. the new analogues, [(L‐2‐Nal)3, (D‐Arg)8]VP is among the most potent antagonists of the vasopressor response to AVP. Moreover, it is the first potent V1antagonist devoid of antiuterotonic activity. This analogue was designed without modification of position 1, which was previously thought to be essential for substantial pressor antagonism. Two other peptides, [Mpa1, (L‐2‐Nal)3, (o‐Arg)8]VP and [Mpa1, (L‐1‐Nal)3, D‐Arg)8]VP, are highly potent V2agonists. The second analogue is highly selective. With the exception of [(L‐2‐Nal)3]AVP, which showed weak antioxytocic activity, (L‐Nal)3modification resulted in the almost complete removal of interaction of our analogues with oxytocic receptorsin vitro.Our results suggest that position 3 in AVP and its analogues is important not only for binding and recognition as previously thought, but also for pressor, antidiuretic and uterotonic activities. We also assume that the hindering effect caused by bulky naphthyl moiety has a significant impact on the bioactive conformations of molecules which contain Nal residue, and can thus influence their interaction with V1, V2and oxytocic receptors. © Munksgaard 1997.
Histidine‐rich human salivary peptides are inhibitors of proprotein convertases furin and PC7 but act as substrates for PC1
Authors: BASAK AJOY , ERNST BLAIR , BREWER DYANNE , SEIDAH NABIL G. , MUNZER JON S. , LAZURE CLAUDE , LAJOIE GILLES A. 
Published: August 2010

A 32 amino acid peptide called histatin‐3 (H3; 22% His) and its TV‐terminal 24 amino acid fragment histatin‐5 (H5, 33% His), are found in human saliva and possess powerful antimicrobial properties. These His‐rich peptides have been synthesized by Fmoc‐based solid‐phase chemistry. Their sequences are: DSHAKRHHGYKRKFHEKHHSHRGYRSNYLYDN (H3) and DSHAKRHHGYKRKFHEKHHSHRGY (H5). In addition, we also prepared two H5 and one H3 mutants. The H5 mutants were: DH5 (all amino acids in D configuration) and H5F (where all His are replaced by Phe at positions 3, 7, 8, 15, 18, 19, 21). The 9–24 segment of H3 with all the His at positions 15, 18, 19, 21 replaced by Tyr was also prepared (Δ1–8H3Y). The behavior of these five peptides was examined with three proprotein convertases (PC's) which possess cleavage specificity directed towards single and pairs of basic residues. These were: human (h)PCl, an endocrine and neural convertase, hfurin and rat (r)PC7, two widely expressed enzymes. All are serine endoproteases belonging to the kexin/subtilisin family. Our in vitro study revealed that H3 behaves as a substrate for PCI, being cleaved by this endoprotease primarily at a site carboxy terminal to the single Arg25 residue (HRGYR↓SN). On prolonged incubation some minor cleavage was also observed C‐terminal to the first Lys Arg6 pairs of basic amino acids namely at: HAKR↓HH, which contains a P4 as well as P'l and P'2 His residues. The second potential site YKRK12‐FH which does not have a P4 basic residues is not cleaved, even upon incubation with excess protease. PCI only poorly cleaves H5 at the same site mentioned above for H3, i.e., at HAKR↓HH. As expected, neither the D‐amino acid analogue (DH5), nor the Phe and Tyr mutant analogues of the long and short histatins, respectively, are cleaved at all.In contrast to the above findings for hPCl, the convertase hfurin did not cleave any of the five synthetic peptides. Instead, H3 and H5 were found to be moderately potent inhibitors of the furin‐mediated cleavage of the pentapeptide pGlu‐Arg‐Thr‐Lys‐Arg‐MCA fluorogenic substrate. This inhibition was reversible and competitive, with an estimated inhibition constant Ki of 1.98 μM for H3 and 2.98 μM for H5. The other analogs exhibited only a moderate to weak inhibition of furin, suggesting that substitution of all His by aromatic residues (Phe or Tyr) drastically reduces their inhibitory potency. When tested against rPC7, H3 exhibited almost identical inhibition profile with a measured Ki of 2.4 μM. The partial sequence identity of H3 to the inhibitory pro‐peptide of furin and PC7 provides a rationale for our observation. © Munksgaard 1997.
Design of ligands for the purification of anti‐MUC1 antibodies by peptide epitope affinity chromatography
Authors: Murray A. , Spencer D.I.R. , Missailids S. , Denton G. , Price M.R. 
Published: August 2010

Abstract: The fine specificity of epitope recognition of the anti‐MUCl mucin monoclonal antibody, C595 has been studied using solid‐phase replacement net (RNET) analysis. Two peptides (RAAP and RPPP) showed increased reactivity with C595 antibody compared with the native epitope (RPAP). These were synthesized as integral motifs within MUCl immunodominant peptides and analyzed by fluorescence quenching (FQ) and circular dichroism (CD). They were also tested as ligands for the purification of C595 antibody using epitope affinity chromatography. Affinity matrices were compared with respect to capacity, affinity, and quality of the purified product.In FQ tests the native epitope peptide (APDTRPAPG) and the alanine substituted peptide had similar association constants when reacting with C595 antibody, whereas the proline substituted peptide (APDTRPPPG) had a higher association constant. This order of affinity for C595 was confirmed in chromatography experiments in which antibody was eluted from the former two peptide matrices at approximately the same point on the NaSCN elution gradient, whereas antibody was desorbed from APDTRPPPG at a higher NaSCN concentration. Circular dichroism analysis showed that the thermodynamically preferred conformation of these peptides in aqueous solution is the P‐II extended helix, the conformation preferred for an extended bound form of the peptide held by interactions with the peptide amides. The stronger binding peptide (APDTRPPPG) has the higher population of the P‐II helix in solution.In conclusion, RNET analysis is useful in the rational design of peptide ligands so that the performance of affinity matrices may be regulated.
The hydrophobic pocket of 24p3 protein from mouse uterine luminal fluid: Fatty acid and retinol binding activity and predicted structural similarity to lipocalins
Authors: Chu S.‐T. , Lin H.‐J. , Huang H.‐L. , Chen Y.‐H. 
Published: August 2010

Abstract: The conformation of 24p3 protein purified from mouse uterine luminal fluid was studied by circular dichroism spectroscopy in 200–300 nm. At pH 7.4, the spectrum in the UV region appears as one negative band with a minimum mean residue ellipticity of ‐3,600 deg.cm2.dmole−1 at 217 nm, suggesting a very low or no helical content, but a considerable amount of β‐form, β‐turn, and unordered form in the protein molecule. This agrees with the predicted secondary structures consisting of only one a‐helical segment of residues 150–163 and nine segments of residues 28–35, 50–60, 67–72, 78–86, 94–97, 106–114, 119–125, 136–140 and 166–172 in β‐forms, which would construct two orthonormal β‐sheets to form a less polar β‐barrel. The environments around Trp‐31 and Trp‐81 of this protein were studied by intrinsic fluorescence and solute quenching. They give an emission peak at 332 nm, and only about 21% of them are accessible to quenching by acrylamide. This together with their low accessibility to either CsCl or KI suggests that they are located in the less polar P‐barrel.Hydrophobic compounds such as fatty acids, retinoids, and cholesteryl oleate in the protein solution diminish the protein fluorescence. Analysis of the fluorescence data suggests that the protein has a binding site for hydrophobic ligand. The association constants for the complex formation are 1.03 × 106M−1, 1.92 × 105M−1, 2.38 × 105M−1 or 1.25 × 105M−1for cholesteryl oleate, oleic acid, retinol, or retinoic acid at pH 7.4. Analysis of the equilibrium binding data from binding assay using [H3]‐retinol and [H3]‐retinoic acid reveals a singular type of retinoid‐binding site in the protein with the association constant of 4.92 × 105M−1 and 1.17 × 105M−1 for retinol and retinoic acid, respectively. Trp‐31 or/ and Trp‐81 is in or very near the binding site and the gross conformation of protein changes considerably as the formation of protein‐ligand complex.
Solid‐phase synthesis and characterization of carcinoembryonic antigen (CEA) domains
Authors: Kaplan B.E. , Hefta L.J. , II R.C. Blake , Swiderek K.M. , Shively J.E. 
Published: August 2010

AbstractCarcinoembryonic antigen (CEA), a 180,000 dalton cell surface glycoprotein expressed on tumors of the colon, breast, ovary, and lung, has seven predicted immunoglobulin‐like domains (N‐A1‐B1‐A2‐B2‐A3‐B3), most of which are recognized by distinct monoclonal antibodies. To study the individual domains, we have prepared several of the domains (N, A3, B3, and A3‐B3) by solid‐phase peptide synthesis. The syntheses were performed by the Fmoc method using single couplings, elevated temperatures for both the coupling and deblocking reactions, and a flexible solvent system for the coupling reactions. The syntheses were accomplished on an in‐house built synthesizer which allowed for temperature control and flexible solvent control during the course of the coupling reactions. Due to the large size of the peptides (84‐184 residues), it was anticipated that the overall purity of the final product would not exceed 60% even for an average coupling yield of 99.5%. Therefore, several of the peptides were synthesized with a His6“tail” at the amino terminus, allowing for purification on a Ni‐NTA chelate column. For the most part, the purified peptides exhibited single sharp peaks by RP‐HPLC, migrated at their expected molecular weights by gel permeation chromatography, gave correct masses by electrospray ionization or matrix‐assisted laser desorption ionization time of flight mass spectrometry, gave the expected amino acid analyses, N‐terminal sequences, and tryptic maps, and bound their appropriate monoclonal antibodies. The N‐domain was extremely hydrophobic, requiring 6m guanidinium hydrochloride for solubilization, the A3 domain was soluble in dilute acid, and the B3 domain had an intermediate solubility. The affinity constants of the A3 domain and several mutants (also made by peptide synthesis) are reported, along with characterization of the 178 amino acid two‐domain peptide, A3‐B3. Although there is no evidence for proper folding of these domains by NMR, their ability to bind monoclonal antibodies with high affinity suggests that this is a plausible approach for producing individual domains of CEA.
Properties of HIV envelope expressed in the presence of SPC3, an Env‐derived peptide drug under phase II clinical trials
Authors: Barbouche R. , Fenouillet E. , Papandréou M.‐J. , Kiény M.P. , Sabatier J M. 
Published: August 2010

AbstractA multibranched peptide construct (SPC3) derived from the conserved sequence of the third variable domain (V3) of the human immunodeficiency virus (HIV) envelope (Env) inhibits HIV infectivity. It is being tested in phase II clinical trials (FDA protocol 257A). Because some Env‐derived peptides inhibit HIV infectivity through alteration of Env biosynthetic pathway, we studied whether SPC3 displays its activity through interference with Env biosynthesis or with its functions at the membrane. Syncytium formation was impaired when human CD4+ cells expressed recombinant HIV Env in the presence of SPC3. This inhibition was not due to an effect of SPC3 on the amount of Env expressed at the cell membrane. As assessed using antibodies, the conformation of the receptor binding site and of V3 presented on membrane Env was not affected by the presence of SPC3 during biosynthesis. Finally, despite the ability of SPC3 to bind to CD4+ cell membrane, SPC3 did not interfere with Env binding to CD4. These data suggest that SPC3 interferes with the infection process at a post‐CD4 binding step, and not with the folding of Env.
The use of synthetic peptides in the design of a consensus sequence vaccine for Pseudomonas aeruginosa
Authors: Cachia P.J. , Glasier L.M.G. , Hodgins R.R.W. , Wong W.Y. , Irvin R.T. , Hodges R.S. 
Published: August 2010

Abstract Pseudomonas aeruginosa employs pili to mediate adherence to epithelial cell surfaces. Research has shown that the C‐terminal region of the pilin monomer contains the epithelial cell binding domain, which is semiconserved in seven different strains of this bacterium. Antibodies to this region of the pilin molecule are also able to block and prevent the infection process. As there is a degree of sequence and structural homology in the C‐terminal region and all strains examined have been shown to bind to the same cell surface receptor, we reasoned that it should be possible to produce a synthetic peptide consensus sequence which would provide cross‐reactive antiserum from a single peptide immunogen inhibiting the adherence of the known strains of P. aeruginosa.In this article we examine the cross‐reactivity of five rabbit polyclonal antisera. One has been raised against the cell‐surface receptor binding domain of native PAK strain pilin (residues 128‐144) while the others have been raised to analogues of this region. Analysis of the cross‐reactivity of these antisera, using competitive ELISA assay, has shown that it is possible to manipulate the amino acid sequence of a peptide immunogen to generate antiserum, which exhibits enhanced cross‐reactivity to various strains of P. aeruginosa. Furthermore, when this peptide is conjugated to tetanus toxoid and used to vaccinate mice it provided cross‐reactive protection against heterologous challenge with PAO strain bacteria.The results of these experiments are analyzed, and the applicability of our hypothesis and the implications of this approach to the design of a strain‐independent consensus vaccine for immunization against Pseudomonas aeruginosa are discussed.
Carboxy‐terminal extension stabilizes the topological stereoisomers of guanylin
Authors: Schulz A. , Escher S. , Marx U.C. , Meyer M. , Rösch P. , Forssmann W‐G. , Adermann K. 
Published: August 2010

Abstract:The peptide hormone guanylin constitutes two topological stereoisomers, which are connected through an equilibrium of interconversion. To investigate the importance of amino acid residues in the central region between the inner cysteines and at the carboxy terminus for this isomerism, synthetic derivatives of guanylin were compared by HPLC, 2D 1H NMR spectroscopy and by their guanylyl cyclase‐C (GC‐C)‐activating potency. An increase in the central sterical bulk by introduction of diiodo‐Tyr9 had virtually no effect on the isomerization kinetics. Compared to guanylin, carboxy‐terminal amidation did not affect the equilibrium between the two isoforms either. In contrast, two significantly stabilized isomers were obtained by extending the carboxy terminus of guanylin with one additional leucine resembling the characteristic of human uroguanylin isomers. This effect was intensified by a further Lys‐Lys extension, thus revealing that the conformational exchange between the guanylin isomers is dependent on the extent of the sterical hindrance in the carboxyterminal region of this peptide. Demonstrated by 2D NMR spectroscopy, the separated isomers of the carboxy‐terminally extended derivatives of guanylin exhibit unambiguously closely related structures as found originally for guanylin isomers, which are only detectable as a mixture. Because only one of the stabilized guanylin isomers activates guanylyl cyclase‐C, the three‐dimensional structure of the GC‐C‐activating guanylin isomer is now defined. The stabilized isoforms of guanylin described in this study represent suitable tools for the separate functional investigation of the GC‐C‐agonistic isomer of guanylin as well as of its isomeric counterpart.
Influence of preformed α‐helix and α‐helix induction on the activity of cationic antimicrobial peptides
Authors: Houston M.E. , Kondejewski L.H. , Karunaratne D.N. , Gough M. , Fidai S. , Hodges R.S. , Hancock R.E.W. 
Published: August 2010

Abstract:One prominent class of cationic antibacterial peptides comprises the α‐helical class, which is unstructured in free solution but folds into an amphipathic α‐helix upon insertion into the membranes of target cells. To investigate the importance of α‐helicity and its induction on interaction with membranes, a series of peptides was constructed based on a hybrid of moth cecropin (amino acids 1‐8) and bee melittin (amino acids 1‐18) peptides. The new peptides were predicted to have a high tendency to form α‐helices or to have preformed α‐helices by virtue of construction of a lactam bridge between glutamate and lysine side‐chains at positions i and i+ 4 at various locations along the primary sequence. In two examples where the use of lactam bridge constraints induced and stabilized α‐helical structure in benign (aqueous buffer) and/or hydrophobic medium, there was a decrease in antibacterial activity relative to the linear counterparts. Thus the preformation of α‐helix in solution was not necessarily beneficial to antimicrobial activity. In the one case where the lactam bridge did result in increased antibacterial activity (lower minimal inhibitory concentration values) it did not increase α‐helical content in benign or hydrophobic medium. Broadly speaking, good activity of the peptides against Pseudomonas aeruginosa correlated best (r2= 0.88) with a helican parameter which was calculated as the induction of α‐helix in α membrane‐mimicking environment divided by the α‐helix formation under benign conditions. Interestingly, the activity of the lactam bridge peptide constructs correlated in part with alterations in bacterial outer or cytoplasmic membrane permeability.