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

The human immunodeficiency virus (HIV) proteins gp120 and gp41 are the principal immune target in HIV infection. One of the most important trends in the study of AIDS is linked to the mapping of sites involving in the binding to the cell receptor CD4 and in the induction of virus-neutralizing antibodies (VNA). Recent studies have revealed that gp120 as the major domain contains inducing type-specific BNA (PND) and a binding region with CD4 (CD4-BR). PND is located in the hypervariable loop of gp120 (residues 301-336 for a BRU strain), and CD4-BR is in the conservation area (residues 410-450). By using the synthetic fragments from these areas (BRU and MN strains) and HIV-infected persons' sera, the authors established that the immune response to PND and CD4-BR is somewhat interrelated: there is a synchronized response of HIV antibodies to peptides from the two regions in ELISA (r = 0.82). For analysis of this phenomenon, experiments with cross-linked immunoreactivity of rabbit antisera to peptides from PND and CD4-BR with homologous and heterologous peptides were performed by applying three control peptides from HIV and hepatitis B virus. It has been found that there is a cross reactivity between rabbit anti-PND (MN, BRU) and anti-CD4-BR abs. Peptide homological analysis revealed common structural elements for PND and CD4-BR despite significant differences in their proposed functions. There is a large amount of positively charged aa within both PND and CD4-BR which may be involved in gp120-CD4 interaction. Acetylation of Lys residues resulted in complete loss of peptide reactivity.
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PMID:[Peptides from the principal neutralizing and CD4-binding domain: similar immunoreactive properties and structure pattern]. 128 21

Seven immortalized B cell clones, five of which secreted specific human monoclonal antibodies (MAbs) against hepatitis B, tetanus toxoid, and Rhesus D antigens, were evaluated for their susceptibility to infection by human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2). Infection was confirmed in three human MAb-producing lines by detection of infectious virus and p24 antigen in culture supernates, by immunofluorescence, and by detection of viral DNA in cells by polymerase chain reaction. The infectable lines were as susceptible to HIV-1 infection as several T cell lines and remained persistently infected for several months, but in contrast to T cell controls, viral cytopathic effects were not observed. Levels of unintegrated viral DNA in the HB1 B cell line were significantly lower than in the HUT78 T cell line. Cell lines that were susceptible to HIV expressed HLA DR, CD20, and CD21, whereas the uninfectable cell lines did not express any of the markers tested. CD4 was undetectable or present on a small percentage of cells in two of the infectable cell lines. However, infection with HIV-1 was blocked more efficiently in B cells than in T cells by soluble CD4, anti-CD4 MAb, and dextran sulphate. The effect of HIV infection on human MAb secretion was variable, being reduced on a per-cell basis in one line, increased in another, and unchanged in a third.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Susceptibility of human monoclonal antibody-producing B cell lines to infection by human immunodeficiency virus. 133 86

The debate over the potential risk of tumorigenicity attributable to the use of CCL substrates for biologicals production has continued for over 30 years and may continue for some time to come. Manufacturers and regulatory agencies are developing scientifically based guidelines for such products. It is currently possible to follow these guidelines to prepare recombinant biologicals and monoclonal antibodies in CCLs which do not pose unreasonable risks. This chapter has attempted to describe the scientific tools available to evaluate the putative risk of tumorigenicity due to potential virus DNA and protein contaminants. No theoretical or experimental basis exists to hypothesize that residual cellular protein might present a significant risk of tumorigenicity. The tools are certainly adequate for characterization of putative risks due to viruses and DNA but are not sufficiently powerful by themselves to assure product safety. The subsequent chapter on process validation describes how adequate assurances of safety ultimately can be obtained for products of CCLs against theoretical risks of tumorigenicity due to putative viruses and DNA. In addition to these safeguards, no evidence of tumorigenicity has been found in human or livestock animal recipients of the products prepared in CCL substrates. Many patients have received inoculations of tissue plasminogen activator, erythropoeitin, factor VIII, soluble CD4, GM-CSF, hepatitis B surface antigen vaccine, and various monoclonal antibodies and other recombinant products of continuous cell lines in clinical trials. For tissue plasminogen activator, large doses of 100 mg per patient or more have been used. At the time of writing over 10 kg of CHO-derived tissue plasminogen activator has been sold since late 1987 for administration to over 100,000 human patients. For recombinant factor VIII, erythropoeitin, and soluble CD4 proteins, chronic administration has been employed. Millions have received polio and rabies vaccines prepared in continuous Vero cells. In addition to this human experience, livestock animals have received annual inoculations of foot-and-mouth virus vaccine prepared in BHK-21 (a highly tumorigenic CCL) for up to 14 years without effect (69). No effects have been reported which might be attributed to oncogenic factors. Thus, scientific tools of characterization and principles of process validation are available to protect patients from putative risks of tumorigenicity associated with products prepared in CCLs. Increasing clinical experience also supports this conclusion.
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PMID:Continuous cell substrate considerations. 137 28

Initial CD4 lymphocyte counts were studied in 244 patients with human immunodeficiency virus (HIV) seroconversion. The CD4 cell counts at initial presentation after seroconversion were normally distributed (mean, 579/mm3; SD, 252). The mean percentage of CD4 cells was 26.1% (SD, 5.6). CD4 cell counts were < 500/mm3 in 41% and < 200/mm3 in 4%. The mean calculated duration of HIV infection was 7.7 months, which was not significantly different between the highest and lowest CD4 count quartiles (8.1 vs. 7.9). Age, sex, race, and serologic evidence of toxoplasmosis, cytomegalovirus, hepatitis B, syphilis, and varicella-zoster virus were not associated with initial low CD4 cell counts; however, never-married men were significantly overrepresented in the lowest quartile. These findings suggest that extensive CD4 lymphocyte depletion is common in early HIV infection and that frequent screening is necessary to identify newly infected patients who would benefit from antiretroviral therapy.
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PMID:Initial low CD4 lymphocyte counts in recent human immunodeficiency virus infection and lack of association with identified coinfections. 140 28

A case is described of an HIV+ man who was successfully treated for Hodgkin's lymphoma, but who later developed non-Hodgkin's lymphoma 3 years later when his immune system became suppressed. The patient was 22 years old when he presented with fever, asthenia, weight loss, and cervical lymphadenopathy. With Hodgkin's lymphoma he also had positive serology for HIV and hepatitis B. He was treated with alternate courses of MOPP and ABVD chemotherapy. In 1990 he again appeared with high fever, progressive cervical, axillary and inguinal lymphadenopathy, with hilar and mediastinal lymph node enlargement on x-ray. CD4 lymphocytes were 577/cubic mm, and the CD4/CD8 ratio was 0.57 (normal 1.8). His cervical lymph node biopsy was classified as non-B non-T large-cell anaplastic lymphoma which was EBV-positive. A Western Blot was positive for small amounts of p24 and p18 antigens. The man was treated with MACOP-B chemotherapy, with some results, but died of sepsis 6 weeks later. The relationships between Hodgkins and non-Hodgkin's lymphoma, the timing of the neoplasm in the course of HIV infection, and the possible re-activation of hepatitis virus were discussed.
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PMID:Non-Hodgkin's lymphoma after prolonged remission of Hodgkin's disease in an HIV-infected patient. 166 42

Previously we showed that mononuclear cells from about half of human T-lymphotropic virus (HTLV)-seropositive persons exhibit spontaneous proliferation in vitro. We sought to determine if proliferation was associated with other immunologic changes characteristic of HTLV infection. The parameters assessed were (1) percentages of lymphocytes expressing CD4 and/or CD25 (interleukin-2 receptor), (2) serum levels of soluble CD25, (3) serostatus for other viruses, (4) anti-HTLV antibody levels, and (5) HTLV type determined by polymerase chain reaction or serologic reactivity with type-specific peptides. The proliferation+ HTLV (PROL+) group, proliferation HTLV (PROL-) group, and control group showed similar percentages of CD4+, CD25+, and CD4+CD25+ lymphocytes; serum levels of soluble CD25 were also similar. Antibodies to cytomegalovirus, hepatitis B core, and hepatitis C were present in similar proportions of PROL+ and PROL+ groups. However, a significant association was found between spontaneous proliferation and anti-HTLV antibody levels; sera from 67% of PROL+ persons, but only 18% of PROL- persons, required dilution to yield absorbance values within the linear range of the anti-HTLV antibody assay. In the PROL+ group, persons whose sera required the most dilution had proliferative responses significantly higher than those whose sera required no dilution. The PROL+ and PROL groups were similar with regard to the relative distribution of HTLV-I and HTLV-II infection. These findings indicate that HTLV-related spontaneous lymphocyte proliferation is related to levels of circulating anti-HTLV antibodies, and characterizes both HTLV-I and HTLV-II infection.
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PMID:Immunologic correlates of spontaneous lymphocyte proliferation in human T-lymphotropic virus infection. 167 16

Both CD4 and CD8 T cells are subdivided into two phenotypically distinct sublineages via another two T cell markers, Leu-8 and CD11b antigens. The proportions of these four T cell subsets, CD4+Leu8+, CD4+Leu8-, CD8+11b+ and CD8+11b-, were studied in patients with auto-immune chronic active hepatitis (CAH) and compared with disease controls (hepatitis B surface antigen positive chronic active hepatitis) and healthy controls. We found that the proportion of CD4+Leu8+ cells was significantly reduced compared with controls (P less than 0.01), whereas those of the other cells were almost identical in all 3 groups. The absolute number of these CD4+Leu8+ cells was also lower than that of controls (P less than 0.01). Thus, the present study suggests that a reduced number of CD4+Leu8+ cells is associated with the aberrant immune response in auto-immune CAH.
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PMID:Dual colour fluorescein analysis of peripheral blood T cells in auto-immune chronic active hepatitis. 168 Apr 81

Clones of hepatitis B surface antigen-reactive CD8+ and CD4+ T cells were obtained from peripheral blood mononuclear cells (PBM) of a hepatitis B immunized individual whose PBM proliferated when cultured with hepatitis B surface antigen (HBsAg). Lymphocytes were activated by culturing for 2 weeks with HBsAg and high concentrations of interleukin-2 (IL-2), then cloned in the presence of irradiated HBsAg-activated PBM and autologous Epstein-Barr virus (EBV)-transformed B cells, together with antigen and IL-2. All clones examined proliferated in an antigen-specific manner. Of 7 clones examined by flow cytometry, 4 were CD4+, CD8-; and 3 were CD4-, CD8+. Several clones produced IL-2 activity after stimulation with hepatitis B surface antigen. Since development of CD8+ T-cell clones specific for soluble antigens is difficult, the high frequency with which CD8+ cells were cloned in these experiments suggests that the cloning strategy employed might have general use for development of CD8+ clones. Availability of hepatitis B virus specific T cell clones of different phenotypes may help elucidate mechanisms of immunotolerance in hepatitis B infection.
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PMID:Hepatitis B surface antigen-specific CD8-positive T cell clones. Antigen specificity and interleukin-2 production. 169 32

Lymphoblastoid interferon is effective therapy in some but not all patients with chronic hepatitis B virus infection. To assess whether immunological parameters were predictive of response to interferon therapy, we determined the human leukocyte antigen type, CD4/CD8 ratio, natural killer cell activity, IgM anti-HBc antibody levels and concanavalin A-induced lymphocyte proliferative response in 30 patients before treatment. In addition, to investigate the mechanisms of action of interferon in promoting hepatitis B virus clearance, we serially measured the CD4/CD8 ratios, natural killer activity and lymphocyte proliferative response at wk 4, 8 and 12 of treatment. A beneficial response to therapy was defined as the sustained clearance of HBeAg and serum hepatitis B virus DNA within 1 yr of commencing therapy. Elevated IgM anti-HBc levels were associated with a beneficial response to therapy, but there was no correlation observed between response and pretreatment CD4/CD8 ratio, natural killer activity or lymphocyte proliferative response. Six of seven human leukocyte antigen DR3-positive patients responded. No measurable changes in the immunological parameters studied were observed in the nonresponder group, whereas a significant rise in CD4/CD8 ratio, associated with a fall in peripheral CD8 number and a decline in measurable NK activity, was seen in the responder group. These changes were maximal at the time of hepatitis B virus DNA clearance, which was associated with a transient increase in hepatic inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Immunological studies before and during interferon therapy in chronic HBV infection: identification of factors predicting response. 169 61

The hepatitis B virus genome encodes a transcriptional transactivator protein designated HBxAg. We have investigated whether this antigen is a target structure for human T-lymphocytes. Using recombinant HBxAg protein, we found HBxAg-specific stimulation of peripheral blood mononuclear cells in patients with acute hepatitis B virus infection (6 of 6) and chronic hepatitis B virus infection (6 of 17) but not in healthy individuals. With HBxAg-specific synthetic polypeptides, several T-cell epitopes were identified. Most were located in the carboxyterminal half of the HBxAg protein. Five T-cell clones specific for a T-cell epitope located at the carboxyterminal region of HBxAg were established and found to belong to the CD2/CD4-positive, CD8-negative subtype. These data establish for the first time HBxAg as an antigen in the cellular immune response.
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PMID:Immune response of peripheral blood mononuclear cells to HBx-antigen of hepatitis B virus. 170 27


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