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)

We investigated the major histocompatibility complex (MHC) class I-restricted presentation of an epitope of the hepatitis B virus small surface (S) antigen particle to cloned murine cytotoxic T lymphocytes (CTL). Efficient Ld-restricted presentation of the S28-39 epitope to CTL is observed in cells of different tissue origin pulsed in vitro, either with the antigenic S28-39 12-mer S-peptide, or with particulate S-antigen. The kinetics of epitope presentation differ in S-peptide-pulsed and in S-particle-pulsed cells: while a 15-min pulse with the antigenic peptide sensitizes targets for class I-restricted CTL lysis, presentation of S-particles requires 30-60 min to sensitize cells for CTL lysis. Uptake of antigenic material and active metabolism of the presenting cell are required for processing of S-particles, but not for sensitizing targets with S-peptides. Intracellular processing and presentation of S-particles is blocked in cells treated with chloroquine, NH4Cl, primaquine, or leupeptin, but not by treatment with cycloheximide or brefeldin A. This processing pathway operates efficiently in peptide-transporter-deficient, Ld-transfected T2 cells, revealing a novel endosomal/lysosomal processing pathway for class I-restricted presentation of peptides derived from exogenous S-particles.
 ...
PMID:Hepatitis B virus small surface antigen particles are processed in a novel endosomal pathway for major histocompatibility complex class I-restricted epitope presentation. 753 71

A total of 133 subjects aged 15 to 55 were followed up, the main group (n = 87), patients with chronic diffuse diseases of the liver caused by hepatitis B virus, and two reference groups, 26 patients with uveitis and 20 normal subjects, 13 and 4 subjects of each group, respectively, were Australian antigen (HBsAg) carriers. Functional disorders of the retina were detected in 93.2% of group 1 patients, as well as intensified local (tears) and total system (blood) autoimmune reactions to tissue-specific retinal S-antigen (mol.mass 48 kD). An increased detection rate of antibodies to S-antigen and its higher titers were found in healthy virus carriers as compared to HBsAg-seronegative donors. These data may be regarded as evidence of an increased risk of uveoretinal pathology in subjects infected with hepatitis B virus, this being confirmed by a higher incidence (50%) of latent virus carriership in the group of patients with uveoretinitis. Stabilizing effect of cavinton in functional changes of the retina was revealed, this recommending this drug for combined therapy of patients with chronic diffuse diseases of the liver and for prevention of ocular diseases. The majority of the examinees in whom retinal abnormalities were found being young, the authors draw attention to the social aspect of the problem.
 ...
PMID:[Clinical and immunological signs of retinal lesions and possibilities of their correction by drugs in patients with chronic diffuse liver diseases of viral etiology and carriers of Australia antigen]. 787 48

In the murine system, we tested in vivo the immunogenicity of different preparations of the yeast-derived surface antigen (S-antigen or S-protein) of hepatitis B virus (HBV). Native S-protein molecules self-assemble into stable 22-nm particles. BALB/c mice immunized with low doses of native S-particles without adjuvants efficiently generated an H-2 class I-restricted CD8+ cytotoxic T lymphocyte (CTL) response, and developed easily detectable serum antibody titers against conformational determinants of the native S-particle or linear epitopes of the denatured S-protein. Disruption of S-particles with sodium dodecyl sulfate and beta-2-mercaptoethanol generated p24 S-monomers. Injection of an equal dose of S-monomers into mice efficiently primed CTL, but did not stimulate an antibody response against conformational or linear epitopes of the native or denatured S-protein. In vivo priming of CTL by S-particles or S-monomers required "endogenous" processing of the antigen because the injection of an equimolar (or higher) dose of an antigenic, S-derived 12-mer peptide into mice did not prime CTL. Native (particulate) or denatured (monomeric) S-antigen injected with mineral oil (incomplete Freund's adjuvant) or aluminum hydroxide failed to stimulate a CTL response. Hence, different preparations can be produced from a small protein antigen which specifically stimulate selected compartments of the immune system.
 ...
PMID:Selective stimulation of murine cytotoxic T cell and antibody responses by particulate or monomeric hepatitis B virus surface (S) antigen. 818 20

Hepatitis B virus (HBV) isolates with A-1762 to T and G-1764 to A mutations in the core promoter have been associated with active hepatitis, severe liver disease following liver transplantation, hepatocellular carcinoma and acute fulminant courses--in the latter case combined with a C-1653 to T mutation. In this study, a mutant core promoter region containing the T-1653, T-1762 and A-1764 mutations was placed into the context of a wild-type HBV genome and analysed by transfection. The mutations reduced the level of pre-C mRNA (by 55%) and e-antigen secretion. In contrast, no significant effects on the levels of pregenome/C and pre-S/S mRNAs, intracellular core, polymerase, and pre-S /S2 proteins and secreted S-antigen were observed. The amount of progeny virus DNA in the cells and in the culture medium was increased marginally, if at all.
 ...
PMID:Wild-type levels of pregenomic RNA and replication but reduced pre-C RNA and e-antigen synthesis of hepatitis B virus with C(1653) --> T, A(1762) --> T and G(1764) --> A mutations in the core promoter. 947 23

Hepatitis B virus (HBV) infection is the leading cause of chronic hepatitis and cirrhosis in Turkey. The prevalence of hepatitis B surface antigen (HBsAg) positivity in Turkey is 5 to 10%. HBV is almost completely preventable with the use of hepatitis B vaccines. The most commonly used vaccine is that which contains the predominant viral surface (S) polypeptide. It elicits protective antibodies in greater than 90% of healthy subjects. A vaccine containing the PreS1 and PreS2 antigenic domains has recently been reported as being more efficient in achieving successful immunization in individuals who have not previously responded to the isolated S-antigen vaccine. In this study, the efficacy of a S and PreS-containing vaccine was compared with that of two different standard isolated S-antigen-containing vaccines in terms of the immunization protection produced against HBV in normal healthy adults who had not previously been immunized. Seventy-six young adults (aged 17-22) were randomly assigned to receive 1 ml (20 micrograms) of either one of two standard S-subunit recombinant hepatitis B vaccines (Engerix B. or Hepavax) or the combined S and PreS subunit vaccine (Gen Hevac B) intramuscularly in the deltoid muscle at 0, 1 and 2 months. Hepatitis B surface antigen antibody titres were measured at 1, 2 and 12 months. A titre > or = 10 IU ml-1 was considered to be protective. All subjects receiving the two standard isolated S-antigen-containing vaccines responded to the vaccination with reasonable antibody titres. One-half to two-thirds of those vaccinated developed high antibody titres (> 100 IU ml-1). In contrast, 9% of those receiving the combined PreS1 and PreS2 plus S antigens failed to respond, as demonstrated by antibody titres below the level considered to be protective. The mean titres at 12 months were 107 +/- 12 IU ml-1 (Engerix B), 102 +/- 12 IU ml-1 (Gen Hevac B) and 117 +/- 12 IU ml-1 (Hepavax Gene). Hence, no important difference in term of response to vaccination was found between the two different types of vaccines. As recombinant S-subunit vaccines are less expensive than those that combine S and PreS antigens, it is suggested that, when immunizing normal healthy adults, a standard isolated S-antigen-containing vaccine should be used.
 ...
PMID:A comparative trial of two surface subunit recombinant hepatitis B vaccines vs a surface and PreS subunit vaccine for immunization of healthy adults. 975 Oct 13

We previously developed a method of detecting drug-resistant mutation of hepatitis B virus (tyrosine (Y)-methionine (M)-aspartic acid (D)-aspartic acid (D) (YMDD) mutation) caused by the antiviral agent lamivudine. Using this method, we also reported that YMDD mutation is present in asymptomatic carriers that had not been administered antiviral agents. Thus, we investigated the clinical characteristics of 18 asymptomatic carriers of hepatitis B virus by various biochemical and virological examinations, and compared the results between five subjects with YMDD mutation and 13 subjects without mutation. Although there was no significant difference in the results of various examinations between the two groups, the quantity of virus was generally small, and S-antigen disappeared in 2 patients in whom YMDD mutation was detected. These results suggest that there is no particular cause for the appearance of mutant viruses, but that they occur spontaneously as they gain fitness and, with a subsequent decrease in the absolute quantity of viruses, become relatively easy to detect.
 ...
PMID:Clinical characteristics of asymptomatic hepatitis B virus carriers with YMDD mutant not treated with lamivudine. 1476 70