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)

Human hybridomas with specificity for recombinant hepatitis B surface antigen (HBSAg) were produced by adoptive transfer of human peripheral blood mononuclear cells prepared from HBSAg-immune donors to CB.17 mice bearing the severe combined immunodeficiency (SCID) phenotype. A total of ten SCID-Hu mice were immunized with recombinant HBSAg. Eight SCID-Hu mice found to have human HBSAg antibody in their serum were sacrificed, and single-cell suspensions were made from their spleens. The SCID-Hu spleen cells were electrofused to the mouse-human fusion partner H7. HBSAg-specific hybridomas were recovered from all fusions. This method may provide the means for the production of other human hybridomas and may, in some cases, circumvent the need for in vitro immunization or Epstein-Barr virus transformation of human B lymphocytes.
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PMID:Immunization of SCID-Hu mice and generation of anti-hepatitis B surface antigen-specific hybridomas by electrofusion. 147 1

SCID mice reconstituted with adult human peripheral blood leukocytes (hu-PBL-SCID mice) make antigen-specific human antibody responses following secondary immunization and can be infected with human immunodeficiency virus 1 (HIV-1), suggesting that they might prove useful for evaluating protective immunity to HIV-1 following vaccination of PBL donors. HIV-seronegative volunteers were immunized with vaccinia expressing HIV-1LAV-1/Bru 160-kDa envelope glycoprotein (vaccinia gp160) and subsequently given booster injections of recombinant gp160 protein (rgp160). Their PBLs were used at intervals of 4-72 weeks after booster injections to construct hu-PBL-SCID mice, which were then challenged with 10(2)-10(3) minimal animal infectious doses of highly homologous HIV-1IIIB. Control hu-PBL-SCID mice were constructed from donors receiving vaccinia, alum, or hepatitis B vaccine. Protection against virus infection was defined as the absence of HIV-1 by culture and no detection of proviral genomes following PCR amplification. Control animals were highly susceptible to HIV infection. By contrast, hu-PBL-SCID mice reconstituted with cells from three of four donors immunized with vaccinia gp160 and recently injected with rgp160 showed no evidence of HIV-1 infection by culture or PCR assays. With increasing time after rgp160 injection, the ability of vaccine-derived hu-PBL-SCID mice to resist HIV-1 infection diminished. These results demonstrate that a potentially protective human immune response was stimulated by this HIV gp160 immunization protocol and show the utility of the hu-PBL-SCID model in the rapid evaluation of candidate vaccines.
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PMID:Resistance to human immunodeficiency virus 1 infection of SCID mice reconstituted with peripheral blood leukocytes from donors vaccinated with vaccinia gp160 and recombinant gp160. 846 Jan 55

DNA-based immunization of mice by intramuscular injection of antigen-encoding plasmid DNA results in immune responses which may be sustained for extended periods of time without an antigen boost. For example, we have previously shown that a strong humoral response against hepatitis B virus surface antigen (HBsAg) will persist for up to 74 weeks following a single intramuscular administration of DNA. It has been proposed that the longevity of the response is due to sustained expression of antigen in transfected muscle cells. However, here we show by immunohistochemistry and electron microscopy that HBsAg-expressing muscle fibers are destroyed around 10 days after injection of DNA in mice. We have also evaluated destruction of the transfected muscle fibers indirectly, by measurement of luciferase activity in muscles at different times after injection of a luciferase reporter gene construct, alone or in combination with HBsAg-expressing DNA. Control muscles injected with luciferase-expressing DNA alone maintain expression of high levels of luciferase for at least 60 days. In contrast, muscles co-injected with DNAs expressing luciferase and a secreted form of HBsAg show high levels of luciferase activity at 5 days but > 99% of this is lost by 20 days. Similar results are obtained with co-expression of luciferase and beta-galactosidase, a non-secreted antigen. Loss of luciferase expression does not occur in muscles of mice with severe combined immunodeficiency, indicating that the myofiber destruction is immunologically mediated.
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PMID:Immune-mediated destruction of transfected muscle fibers after direct gene transfer with antigen-expressing plasmid DNA. 913 31

Hepatocellular carcinoma (HCC) frequently overexpresses the MDR1 gene and is resistant to drugs transported by the multidrug-resistance efflux pump. A xanthine analog, 1-(11-dodecylamino-10-hydroxyundecyl)-3,7-dimethylxanthine (CT-2584,CTI), is cytotoxic to many tumors in culture and was four times more effective than verapamil in inhibiting Rhodamine 123 secretion in MDR1-overexpressing Chinese hamster ovary cells. However, studies using PRF/PLC/5 (Alexander) cells revealed that CT-2584 is cytotoxic by another mechanism not involving inhibition of MDR1 function. Alexander cells have integrated the hepatitis B surface antigen (HBsAg) gene and quantitatively secrete HBsAg. The parent cell line, Alex 0, has low MDR1 expression and is drug-sensitive, whereas a derived line, Alex 0.5, is drug-resistant and overexpresses MDR1 100 times. Both cell lines were similarly killed within 24 or 48 hours by CT-2584. Freshly isolated rat and human hepatocytes were considerably more resistant to killing by CT-2584. In vivo, CT-2584 significantly reduced tumor growth in SCID mice bearing Alex 0 or 0.5 xenografts as determined by serial measurements of HBsAg. Hepatic parenchyma was normal, whereas apoptosis and cellular loss were observed in xenografts. The xenograft model is useful for testing pharmacological therapy of HCC.
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PMID:Effect of a xanthine analog on human hepatocellular carcinoma cells (Alexander) in culture and in xenografts in SCID mice. 936 62

A murine model in which to study multiple drug resistance in human hepatocellular carcinoma was developed. PRF/PLC/5 hepatoma cells (Alex 0) and an induced multidrug resistant clone (Alex 0.5) were injected intrasplenically into severe combined immunodeficiency mice. In 70% of injected mice, hepatoma cells engrafted in the liver and grew as intrahepatic metastasis. Since Alex cells contain an integrated hepatitis B virus genome and secrete hepatitis B surface antigen (HBsAg), the serum HBsAg concentration in tumor-bearing mice was used to quantitate tumor burden. Tumor wet weight determined at necropsy was directly proportional to the serum HBsAg concentration. In Alex 0 cells, IC50s for doxorubicin, vinblastine, and cis-platinum were 0.35 microM, 0.029 microM, and 3.70 microM, respectively. Alex 0.5 cells were 25-, 14-, and 1.4-fold more resistant to doxorubicin, vinblastine, and cis-platinum, respectively. Immunoblotting of Alex 0 cell membranes with an anti-P-glycoprotein antibody (C219) revealed small amounts of P-glycoprotein, whereas Alex 0.5 membranes overexpressed the protein. Concurrent exposure to verapamil (10 microM) sensitized both cell lines to the cytotoxic action of vinblastine and doxorubicin but had no effect on the cytotoxicity of cis-platinum. Mice bearing intrahepatic xenografts derived from Alex 0 and 0.5 cells had no response to treatment with i.v. vinblastine or doxorubicin, as was anticipated from in vitro drug testing. Addition of verapamil to vinblastine treatment did not improve the success of in vivo chemotherapy. Immunotherapy with a human anti-P-glycoprotein antibody (MRK16) suppressed the in vivo growth of tumors derived from both cell lines. The effect was most pronounced in mice bearing Alex 0.5 tumors. Immunoblotting of tumors which initially responded to MRK16 therapy, but subsequently relapsed, revealed a marked decrease in P-glycoprotein expression when compared to results in tumors that were untreated or treated with vinblastine or control antibody. In summary, we have developed an intrahepatic tumor xenograft model of human hepatocellular carcinoma in mice that permits noninvasive serial quantification of tumor burden by determination of serum HBsAg levels and demonstrated a positive response to immunotherapy with anti-P-glycoprotein antibodies.
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PMID:Establishment and serial quantification of intrahepatic xenografts of human hepatocellular carcinoma in severe combined immunodeficiency mice, and development of therapeutic strategies to overcome multidrug resistance. 981 20

Previous studies have demonstrated the feasibility of implantation of human blood cells or tissues in lethally irradiated mice or rats, radioprotected with SCID mouse bone marrow cells: The Trimera system. In the present study, we describe the development of a mouse Trimera model for human hepatitis B virus (HBV) infection. In this model, viremia is induced by transplantation of ex vivo HBV-infected human liver fragments. Engraftment of the human liver fragments, evaluated by hematoxylin-eosin staining and human serum albumin mRNA expression, was observed in 85% of the transplanted animals 1 month postimplantation. Viremia levels were determined in these mice by measuring serum HBV DNA using polymerase chain reaction (PCR), followed by dot-blot hybridization. HBV DNA is first detected 8 days after liver transplantation. Viremia attains a peak between days 18 and 25 when HBV infection is observed in 85% of the transplanted animals. The HBV-Trimera model was used to evaluate the therapeutic effects of human polyclonal anti-HBs antibodies (Hepatect) and of two reverse-transcriptase inhibitors, lamivudine (3TC) and beta-L-5-fluoro-2',3'-dideoxycytidine (beta-L-5FddC). Treatment of HBV-Trimera mice with these drugs effectively reduced both the percentage of infected animals and the viral load in their sera. Treatment cessation resulted in rebound of viral load, indicating HBV replication upon drug withdrawal. These results show that the HBV-Trimera model represents a novel experimental tool for simulating human HBV infection and evaluating potential anti-HBV therapeutic agents.
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PMID:The hepatitis B virus-trimera mouse: a model for human HBV infection and evaluation of anti-HBV therapeutic agents. 991 35

Adoptive transfer of human peripheral blood mononuclear cells (PBMC) into mice with severe combined immunodeficiency (SCID) or into lethally irradiated BALB/c mice radioprotected with SCID bone marrow, leads to marked engraftment of human T and B cells. In such chimeras, human serum antibody responses can be stimulated readily by vaccination with recall antigens, but the detection of antigen-specific functional T or B cells has been extremely difficult. In the present study, we were able to detect by Elispot analysis high frequencies of immunoglobulin G (IgG)-secreting B cells and mitogen-responsive interferon-gamma (IFN-gamma) or interleukin-4 (IL-4)-secreting T cells in peritoneum and spleen of human/BALB/c chimeric mice during the first 3 weeks after PBMC transfer. Moreover, specific memory responses were elicited by vaccination with tetanus toxoid (TT) or hepatitis B virus (HBV) surface (HBs) antigen of chimeric mice transplanted with PBMC derived from TT- or HBV-immune donors. Substantially higher TT-specific B-cell frequencies were found during the first 3 weeks after vaccination in mice challenged with the specific antigen compared to the levels found in control animals. High numbers of TT-specific IFN-gamma-secreting T cells persisted in the peritoneum of vaccinated, but not of unvaccinated, animals during the entire observation period, but only low numbers of specific IL-4-secreting T cells were found in vaccinated mice. Similar results were achieved following vaccination with HBs antigen of chimeric mice, transplanted with PBMC of HBV immunized donors. Thus, TT or HBsAg-specific antibody responses in our model correlate closely with the existence of specific IFN-gamma-secreting T helper 1/0 cells. Furthermore, these results show that adoptive transfer of human PBMC into lethally irradiated mice provides an efficient approach to generate specific B-cell fusion partners for the production of human monoclonal antibodies and specific T-cell lines for adoptive cell therapy of malignant or infectious diseases.
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PMID:Antigen-specific B and T cells in human/mouse radiation chimera following immunization in vivo. 1023 52

We used recombinant SV40 (rSV40)-derived vectors to deliver transgenes to human and simian hematopoietic progenitor cells in culture, and in vivo after transduction ex vivo. rSV40 are highly efficient vectors that are made in very high titers. They infect almost all cells, whether resting or dividing. Two rSV40s were used: SV(HBS), carrying hepatitis B surface antigen as a marker; and SV(Aw) carrying IN#33, a single chain Fv antibody against HIV-1 integrase. CD34+ cells derived from human fetal bone marrow (HFBM) and rhesus macaque bone marrow were transduced once with SV(HBS) without selection. On average 60% of colonies derived from transduced CD34+ cells carried and expressed HBsAg, as assessed by PCR and immunochemistry. Transgene carriage persisted following differentiation of transduced rhesus CD34+ cells into T lymphocytes. In an effort to increase the percentage of gene-marked cells, three sequential treatments of CD34+ cells were done using SV(Aw), without selection. Two weeks later, >95% of colonies expressed IN#33. Unselected SV(Aw)-transduced CD34+ cells from HFBM were transplanted into sublethally irradiated SCID mice. Bone marrow harvested 3 months later showed that >50% of bone marrow cells expressed IN#33. This is comparable with the percentage of human cells in these animals' bone marrow as judged by immunostaining for human CD45. The stability and longevity of transduction in this setting suggests that rSV40 vectors integrate into the cellular genome. This possibility was supported by finding that PCR of genomic DNA using primer pairs with one cellular and one viral primer yielded PCR products only in transduced, but not control, cells. These PCR products hybridized with an SV40 DNA fragment. Thus, rSV40 vectors transduce normal human and primate bone marrow progenitor cells effectively without selection, and maintain transgene expression in vivo following reimplantation. Such high efficiency transduction may be useful in treating diseases of CD34+ cells and their derivatives.
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PMID:Efficient gene transfer to hematopoietic progenitor cells using SV40-derived vectors. 1084 27

A weakness of the hu-PBL-SCID model for the study of human immune functions is the appearance of anergy and the consequent loss of T cell function. We demonstrate here that human T cells retain normal functions during the early stage of chimerism. At 1 and 2 weeks post-engraftment, T cells isolated from the peritoneal cavity of hu-PBL chimeras could be activated and proliferated upon stimulation with phytohaemagglutinin (PHA) or specific antigens to which the cell donor was known to be immune. T cells derived from hu-PBL-SCID and hu-PBL-NOD/LtSz-scid (NOD/SCID) mice not only proliferated but also produced interferon-gamma (IFN-gamma) and IL-5 following in vitro stimulation with tetanus toxoid (TT) or hepatitis B surface antigen (HBsAg). These antigen-specific T cells could only be demonstrated when cognate antigen was administered together with or immediately following the PBL transfer. Without an early rechallenge with antigen in vivo, no TT- or HBsAg-specific T cell responses could be elicited, showing the vulnerability and antigen-dependence of the T cell response. Vigorous anti-TT or anti-HBs responses could be observed in all chimeras. Administration of antigen together with the PBL graft enhanced the humoral anti-TT response in SCID and NOD/SCID mice but had little effect on the anti-HBs antibody response in NOD/SCID mice. These data confirm the observation that the B cell compartment in hu-PBL-SCID chimera is largely antigen-independent and extend this to SCID/NOD.
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PMID:Antigen-specific T cell responses in human peripheral blood leucocyte (hu-PBL)-mouse chimera conditioned with radiation and an antibody directed against the mouse IL-2 receptor beta-chain. 1101 27

The hepatitis B virus (HBV) core (HBc) antigen (HBcAg) is a highly immunogenic subviral particle. Studies with mice have shown that HBcAg can bind and activate B cells in a T-cell-independent fashion. By using a human peripheral blood leukocyte (hu-PBL)-Nod/LtSz-Prkdc(scid)/Prkdc(scid) (NOD/SCID) mouse model, we show here that HBcAg also activates human B cells in vivo in a T-cell-independent way. HBcAg was capable of inducing the secretion of HBcAg-binding human immunoglobulin M (IgM) in naive human B cells derived from adult human and neonatal (cord blood) donors when these hu-PBL were transferred directly into the spleens of optimally conditioned NOD/SCID mice. No such responses were found in chimeric mice that were given hu-PBL plus HBV e antigen or hu-PBL plus phosphate-buffered saline. In addition, HBcAg activated purified human B cells to produce anti-HBc IgM in the chimeric mice, thus providing evidence that HBcAg behaves as a T-cell-independent antigen in humans. However, HBcAg-activated hu-PBL from naive donors were unable to switch from IgM to IgG production, even after a booster dose of HBcAg. Production of HBcAg-specific IgG could only be induced when hu-PBL from subjects who had recovered from or had an ongoing chronic HBV infection were transferred into NOD/SCID mice. Our data suggest that humans also have a population of naive B cells that can bind HBcAg and is subsequently activated to produce HBcAg-binding IgM.
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PMID:Hepatitis B virus core antigen binds and activates naive human B cells in vivo: studies with a human PBL-NOD/SCID mouse model. 1141 2


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