Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The crystal structure of Fab of an Ab PC283 complexed with its corresponding peptide Ag, PS1 (HQLDPAFGANSTNPD), derived from the hepatitis B virus surface Ag was determined. The PS1 stretch Gln2P to Phe7P is present in the Ag binding site of the Ab, while the next three residues of the peptide are raised above the binding groove. The residues Ser11P, Thr12P, and Asn13P then loop back onto the Ag-binding site of the Ab. The last two residues, Pro14P and Asp15P, extend outside the binding site without forming any contacts with the Ab. The PC283-PS1 complex is among the few examples where the light chain complementarity-determining regions show more interactions than the heavy chain complementarity-determining regions, and a distal framework residue is involved in Ag binding. As seen from the crystal structure, most of the contacts between peptide and Ab are through the five residues, Leu3-Asp4-Pro5-Ala6-Phe7, of PS1. The paratope is predominantly hydrophobic with aromatic residues lining the binding pocket, although a salt bridge also contributes to stabilizing the Ag-Ab interaction. The molecular surface area buried upon PS1 binding is 756 A(2) for the peptide and 625 A(2) for the Fab, which is higher than what has been seen to date for Ab-peptide complexes. A comparison between PC283 structure and a homology model of its germline ancestor suggests that paratope optimization for PS1 occurs by improving both charge and shape complementarity.
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PMID:Crystal structure of an antibody bound to an immunodominant peptide epitope: novel features in peptide-antibody recognition. 1112 Aug 21

Several cytotoxic T lymphocyte peptide-based vaccines against hepatitis B, human immunodeficiency virus and melanoma were recently studied in clinical trials. One interesting melanoma vaccine candidate alone or in combination with other tumor antigens, is the decapeptide ELA. This peptide is a Melan-A/MART-1 antigen immunodominant peptide analog, with an N-terminal glutamic acid. It has been reported that the amino group and gamma-carboxylic group of glutamic acids, as well as the amino group and gamma-carboxamide group of glutamines, condense easily to form pyroglutamic derivatives. To overcome this stability problem, several peptides of pharmaceutical interest have been developed with a pyroglutamic acid instead of N-terminal glutamine or glutamic acid, without loss of pharmacological properties. Unfortunately compared with ELA, the pyroglutamic acid derivative (PyrELA) and also the N-terminal acetyl-capped derivative (AcELA) failed to elicit cytotoxic T lymphocyte (CTL) activity. Despite the apparent minor modifications introduced in PyrELA and AcELA, these two derivatives probably have lower affinity than ELA for the specific class I major histocompatibility complex. Consequently, in order to conserve full activity of ELA, the formation of PyrELA must be avoided. Furthermore, this stability problem is worse in the case of clinical grade ELA, produced as an acetate salt, like most of the pharmaceutical grade peptides. We report here that the hydrochloride salt, shows higher stability than the acetate salt and may be suitable for use in man. Similar stability data were also obtained for MAGE-3, another N-terminal glutamic acid containing CTL peptide in clinical development, leading us to suggest that all N-terminal glutamic acid and probably glutamine-containing CTL peptide epitopes may be stabilized as hydrochloride salts.
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PMID:Stability and CTL activity of N-terminal glutamic acid containing peptides. 1143 56

Hepatitis B virus (HBV) is an enveloped DNA virus with a spherical capsid (or core). The capsid is constructed from 120 copies of the homodimeric capsid protein arranged with T = 4 icosahedral symmetry. We examined in vitro assembly of purified E. coli expressed HBV capsid protein. After equilibration, concentrations of capsid and dimer were evaluated by size exclusion chromatography. The extent of assembly increased as temperature and ionic strength increased. The concentration dependence of capsid assembly conformed to the equilibrium expression: K(capsid) = [capsid]/[dimer](120). Given the known geometry for HBV capsids and dimers, the per capsid assembly energy was partitioned into energy per subunit-subunit contact. We were able to make three major conclusions. (i) Weak interactions (from -2.9 kcal/mol at 21 degrees C in low salt to -4.4 kcal/mol at 37 degrees C in high salt) at each intersubunit contact result in a globally stable capsid; weak intersubunit interactions may be the basis for the phenomenon of capsid breathing. (ii) HBV assembly is characterized by positive enthalpy and entropy. The reaction is entropy-driven, consistent with the largely hydrophobic contacts found in the crystal structure. (iii) Increasing NaCl concentration increases the magnitude of free energy, enthalpy, and entropy, as if ionic strength were increasing the amount of hydrophobic surface buried by assembly. This last point leads us to suggest that salt acts by inducing a conformational change in the dimer from an assembly-inactive form to an assembly-active form. This model of conformational change linked to assembly is consistent with immunological differences between dimer and capsid.
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PMID:Weak protein-protein interactions are sufficient to drive assembly of hepatitis B virus capsids. 1226 96

Hepatitis B virus (HBV) transgenic mice (official designation, Tg [Alb-1 HBV] Bri 44) invariably develop macroscopically evident tumors within the 20th month of life. Sustained proliferative activity seems to play an important role in the development of these lesions. We previously showed that ursodeoxycholate (UDC) stimulates hepatocyte proliferation in various experimental settings. Herein, we tested the assumption that biological factors able to further increase liver cell proliferation, such as UDC, could accelerate tumor development in this animal model. For this study, 22 eight-week-old male transgenic mice were divided into 2 groups; 11 animals received a standard diet, and 11 received a UDC-enriched diet. The 2 groups were further divided into 2 subgroups of 5 and 6 animals each and were sacrificed at 3 and 15 months of age, respectively. These different times were chosen to exclude diet-related toxicity (in 3-month-old mice) and evaluate tumor growth (in 15-month-old mice). In addition, hepatocyte proliferation was assessed in all animals. In 3-month-old mice receiving UDC, cholestatic and cytolytic indices as well as liver histology were comparable to those in controls. At 15 months, all UDC-treated mice showed large multinodular tumors whereas only 33% of controls developed smaller uninodular neoplasms. Hepatocyte proliferation was increased in all animals receiving UDC compared with controls. In conclusion, the increase in serum UDC (undetectable in mice fed a standard diet), in the absence of any toxic effect on the liver, suggests the involvement of this bile salt in the stimulation of hepatocyte proliferation and tumor growth.
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PMID:Influence of ursodeoxycholate-enriched diet on liver tumor growth in HBV transgenic mice. 1266 81

About 10% of the Chinese population are chronic carriers of hepatitis B virus (HBV). Thus, the development of a highly efficient process for the preparation of a vaccine based on a recombinant hepatitis B surface antigen (HBsAg) is very important to the Chinese national immunization program. To this end, the ion exchange chromatography recovery of CHO-HBsAg from a recombinant Chinese hamster ovary cell line was shown to increase from about 55 to 80% by the addition of 1% poly(ethylene glycol) (PEG 10,000) to the mobile phase. Furthermore, based on analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), the intact glycoprotein form of CHO-HBsAg was completely preserved by the addition of PEG. In the absence of PEG the glycoprotein form of CHO-HBsAg was also spread out into the high salt elution fraction. High-performance size-exclusion chromatography with on-line multiangle-laser-light scattering (HPSEC-MALLS) analysis was performed to monitor the status of the CHO-HBsAg aggregate structure assembly, particle size and molecular weight distribution after each purification step, and the results showed further that the presence of PEG facilitated the separation and recovery of intact glycoprotein form of CHO-HBsAg and promoted their assembly to proper virus-like particles, which are both important features and prerequisites of their immunogenicity.
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PMID:Ion-exchange chromatography of hepatitis B virus surface antigen from a recombinant Chinese hamster ovary cell line. 1627 91

A 39-yr-old male with hepatorenal syndrome type 1 and refractory ascites was treated with continuous renal replacement therapy (CRRT) resulting in clinical improvement. He was positive for antibodies to hepatitis B, C, and human immunodeficiency viruses, and had a history of chronic alcohol and iv drug abuse. The patient had 4 hospital admissions during a 12-wk period. He first presented with advanced liver disease including pedal edema and a serum ammonia level of 56 micromol/L (reference range: 11 - 35 micromol/L). In subsequent admissions, he had asterixis, nausea, vomiting, jaundice, and worsening pedal edema. On his 4th admission, there was lethargy, tense ascites, decreased urinary output, bilateral edema of the lower extremities and scrotum, serum creatinine of 6.2 mg/dl (reference range: 0.6 - 1.5 mg/dl), and weight gain of 16 kg during the prior 8 wk. During the first 3 hospitalizations, he was treated with lactulose with slight improvement. On the 4th admission, he was started on low-dose dopamine (3 microg/kg/min) and 25% salt-poor albumin without clinical improvement. A pulmonary artery catheter was placed and hemofiltration by CRRT was performed for 5 days, with removal of 26.7 L of fluid and a net reduction of 11 kg of body weight. Serum creatinine decreased to 4.2 mg/dl during CRRT and was 2.2 mg/dl at hospital discharge 2 weeks later. His PaO(2) improved from 66 to 78 mmHg and his systemic vascular resistance increased from 571 to 799 dyne.sec/cm(5). CRRT was effective in relieving severe fluid retention and producing marked clinical improvement. We suggest that CRRT should be considered for the treatment of refractory ascites including that caused by hepatorenal syndrome.
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PMID:Hepatorenal syndrome: resolution of ascites by continuous renal replacement therapy in an alcoholic coinfected with hepatitis B, C, and human immunodeficiency viruses. 1650 Dec 43

The electron microscope provides a powerful tool for investigating the structure of biological complexes such as viruses. A modern instrument is fully capable of atomic resolution on suitable non-biological specimens, but biological materials are difficult to preserve, owing to their fragility, and to image, owing to their radiation, sensitivity. The act of imaging the specimen severely damages it. Originally, samples were prepared by staining with a heavy metal salt, which provides a stable specimen but limits the amount of details that can be retrieved. Now particulate specimens, such as viruses, are prepared by rapid freezing of unstained material and observed in a frozen state with low doses of electrons. The resulting images require extensive computer processing to extract fully detailed three-dimensional information about the specimen. The whole process is referred to as single-particle electron cryomicroscopy. Using this approach, the structure of the human hepatitis B virus core was solved at the level of the protein fold. By comparing maps of RNA- and DNA-containing cores, it was possible to propose a model for the maturation and control of the envelopment of the virus during assembly. These examples show that cryomicroscopy offers great potential for understanding the structure and function of complex biological assemblies.
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PMID:The Leeuwenhoek lecture 2006. Microscopy goes cold: frozen viruses reveal their structural secrets. 1769 55

Novel hydrophobic absorbents were synthesized by immobilizing butyl derivative onto the highly cross-linked agarose beads manufatured in China, which are used as matrix. The effect of the spacer arm length (3C, 8C and 10C) and ligand density (from 13 to 45 micromol/mL) on the hydrophobicity were investigated using purified Hepatitis B surface antigen (HBsAg) expressed by CHO cell lines. Also considering the effects of salt concentration and pH on HBsAg recovery and purification factor, orthogonal experiment design method was used to evaluated the absorbents. The results showed the butyl-S absorbent with the spacer arm length of C8, the ligand density of 22 micromol/mL gel showed the best performance for the separation of HBsAg. Approximately 100% HBsAg recovery and 60 as purification fold were achieved by this media under the operating condition of pH 7.0 and 9% of salt concentrateion.
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PMID:[Comparison of adsorbent with varying arm length and ligand density for the purification of recombinant hepatitis B virus surface antigen]. 1782 46

12B75, 274150; Abacavir sulfate/lamivudine, Abatacept, Ad2/HIF-1alpha, Adalimumab, Adefovir, Adefovir dipivoxil, AGN-201904-Z, AIDSVAX, Albinterferon alfa-2b, Alemtuzumab, Aliskiren fumarate, Alvimopan hydrate, Amlodipine besylate/atorvastatin calcium, Amlodipine besylate/Olmesartan medoxomil, Ammonium tetrathiomolybdate, Amodiaquine, Apaziquone, Aprepitant, Arsenic trioxide, Artesunate/Amodiaquine, Ascorbic acid, Atazanavir sulfate, Atazanavir/ritonavir, Atomoxetine hydrochloride, Atrigel-Leuprolide, Axitinib; Bevacizumab, Binodenoson, Bortezomib, Bovine lactoferrin; Calcipotriol/betamethasone dipropionate, Carisbamate, Certolizumab pegol, Ciclesonide, Conivaptan hydrochloride, CP-690550, CP-751871, Cypher; Dapivirine, Darbepoetin alfa, Darunavir, Dasatinib, del-1 Genemedicine, Denosumab, Desloratadine, Dexlansoprazole, DiabeCell, Drospirenone/ethinylestradiol, DTaP-HepB-IPV, Duloxetine hydrochloride, Dutasteride; Eculizumab, Eldecalcitol, Eletriptan, Emtricitabine, Entecavir, Eritoran tetrasodium, Ertapenem sodium, Escitalopram oxalate, Eslicarbazepine acetate, Esomeprazole magnesium, Estradiol acetate, Eszopiclone, ETEC vaccine, Etoricoxib, Exenatide, Ezetimibe; Fluticasone furoate, Fosmidomycin, Fosmidomycin/clindamycin; Glutamine; Heat Shock Protein 10, Hepatitis B hyperimmunoglobulin, HIV vaccine, Hochuekki-to, Human Albumin, Human papillomavirus vaccine; Immune globulin subcutaneous [human], IMP-321, Interferon omega, ISIS-301012, Istaroxime; Japanese encephalitis virus vaccine; Latanoprost/timolol maleate, Lenalidomide, Linaclotide acetate, Lumiracoxib, LY-517717; Malaria vaccine, MAS-063D, Meningitis B vaccine, Mepolizumab, Methylnaltrexone bromide, Micafungin sodium, MK-0822A, Morphine glucuronide, Morphine hydrochloride, Mycophenolic acid sodium salt; Natalizumab, Nesiritide, Norelgestromin/ethinyl estradiol, NT-201; Oblimersen sodium, Olmesartan medoxomil, Olmesartan medoxomil/hydrochlorothiazide, Omalizumab, Otamixaban; Paclitaxel nanoparticles, Panitumumab, Panobinostat, Parathyroid hormone (human recombinant), Parecoxib sodium, Pegfilgrastim, Peginterferon alfa-2a, Peginterferon alfa-2b, Pegvisomant, PI-88, Pimecrolimus, Pneumococcal 7-valent conjugate vaccine, Pneumococcal 9-valent conjugate vaccine, Pneumococcal conjugate vaccine, Poloxamer-188, Prasugrel, Pregabalin, Prulifloxacin; R-109339, Ramipril/amlodipine, Ranolazine, Rasburicase, rHA influenza vaccine, Ro-50-3821, Rosuvastatin calcium, Rotavirus vaccine, Rotigotine, Ruboxistaurin mesilate hydrate; Satavaptan, SC-75416, Solifenacin succinate, Sorafenib, Sugammadex sodium, Sunitinib malate, Synthetic conjugated estrogens B; Tadalafil, Talnetant, Taxus, Tegaserod maleate, Telbivudine, Temsirolimus, Tenofovir disoproxil fumarate, Tetomilast, Tiotropium bromide, Tipifarnib, Tofimilast, Tremelimumab, Trimethoprim; Udenafil, Urocortin 2; Valdecoxib, Vernakalant hydrochloride; XP-828L.
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PMID:Gateways to clinical trials. 1798 11

Adefovir dipivoxil, a marketed drug for the treatment of hepatitis B, is dosed at submaximally efficacious doses because of renal toxicity. In an effort to improve the therapeutic index of adefovir, 1-aryl-1,3-propanyl prodrugs were synthesized with the rationale that this selectively liver-activated prodrug class would enhance liver levels of the active metabolite adefovir diphosphate (ADV-DP) and/or decrease kidney exposure. The lead prodrug (14, MB06866, pradefovir), identified from a variety of in vitro and in vivo assays, exhibited good oral bioavailability (F = 42%, mesylate salt, rat) and rate of prodrug conversion to ADV-DP. Tissue distribution studies in the rat using radiolabeled materials showed that cyclic 1-aryl-1,3-propanyl prodrugs enhance the delivery of adefovir and its metabolites to the liver, with pradefovir exhibiting a 12-fold improvement in the liver/kidney ratio over adefovir dipivoxil.
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PMID:Pradefovir: a prodrug that targets adefovir to the liver for the treatment of hepatitis B. 1817 34


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