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Biomedical subjects

J Gerin

Publications and source records attributed to J Gerin.

At least 19 recordsLinked to original sources
PubMed1999

Licensed recombinant hepatitis B vaccines protect chimpanzees against infection with the prototype surface gene mutant of hepatitis B virus.

The emergence in vaccinated individuals of hepatitis B virus (HBV) mutants with amino acid substitutions within the a determinant of the surface protein has raised the possibility that such variants represent neutralization escape mutants. We previously demonstrated that one such mutant HBV, strain AS, with an arginine substituted for glycine at surface gene codon 145, was infectious and pathogenic in seronegative chimpanzees. In the present study, the protective efficacy of licensed hepatitis B vaccines was evaluated against challenge with this mutant virus. Four chimpanzees were immunized with 1 of 2 licensed recombinant hepatitis B vaccines. Shortly after the chimpanzees developed antibodies to hepatitis B surface antigen (anti-HBs), they were challenged intravenously with mutant HBV strain AS. Two unvaccinated chimpanzees served as positive controls. The 4 vaccinated chimpanzees did not develop evidence of HBV infection or hepatitis during 2 years following virus challenge. In contrast, the 2 unvaccinated chimpanzees developed HBV infection and hepatitis. Serum anti-HBs in the vaccinated chimpanzees reacted not only with wild-type surface antigen, but also with mutant surface antigen by competition enzyme-linked immunosorbent assay (ELISA). Thus, immunization of chimpanzees with licensed recombinant hepatitis B vaccines stimulates anti-HBs that is broadly reactive and affords protection against infection with a surface gene mutant of HBV, suggesting that properly immunized individuals are not at significant risk of infection with this prototype variant strain of HBV.

Animals↗
PubMed1993

New enzyme immunoassays for the serologic detection of woodchuck hepatitis virus infection.

The woodchuck and the woodchuck hepatitis virus (WHV) have been used as a model of hepatitis B virus infection and its disease sequelas. Serologic responses to WHV infection have been described in previous reports from this laboratory by using virus-specific radioimmunoassays (RIAs) for WHV surface antigen, antibody to WHV core antigen, and antibody to WHsAg. In this study, we developed and evaluated new enzyme immunoassays (EIAs) for these WHV serologic markers. Relative to the established RIAs, the EIAs were either improved or comparable in their sensitivity and specificity, and in their utility for monitoring experimental WHV infection and classifying woodchucks into serological diagnostic categories. These EIA systems are amenable to the quantitative titration of antibodies and quantitation of WHV antigens in serum, and ultimately should allow improved resolution of virologic and humoral immune responses of woodchucks to WHV infection.

Animals↗
PubMed1989

Treatment of chronic hepatitis delta virus (HDV) infection with human lymphoblastoid alpha interferon.

Ten patients with evidence of continuing HDV replication were treated with lymphoblastoid alpha-interferon and eight more were followed as a non-randomized control group. Four out of eight patients who completed one year of follow-up had cleared HDV-RNA from the serum whilst none of the control group did so. In these four responding cases there was a transient increase in transaminase levels during treatment and in two, this was followed by improvement. One patient also cleared HBV and seroconverted to anti-HBs (antibody to hepatitis B surface antigen--HBsAg). In one patient with sustained loss of HDV, recurrence of HDV infection was detected 18 months after completion of treatment. These data suggest that alpha-interferon can inhibit HDV replication in the short term but relapse after one to two years may occur. Inhibition of HDV-RNA is associated with improvement in the inflammatory liver disease and now larger studies are required to determine whether it influences survival.

Adult↗
PubMed1988

Molecular cloning of hepatitis delta virus RNA from an infected woodchuck liver: sequence, structure, and applications.

cDNA prepared from the single-stranded circular RNA genome of hepatitis delta virus was cloned in lambda gt11 by using RNA from the liver of an infected woodchuck. From the sequence of overlapping clones, we assembled the full sequence of 1,679 nucleotides. The sequence indicated an exceptional ability for intramolecular base pairing, yielding a rod structure with at least 70% of the bases paired and a predicted free energy of -805 kcal (-3,368 kJ)/mol. Three of the lambda clones contained sequences that were not only expressed as fusion proteins with beta-galactosidase but were recognized by human hepatitis delta virus-specific antibody. These clones were sequenced so as to establish the reading frame of the delta antigen on the antigenomic strand. The fusion protein produced by one clone was purified by immunoaffinity chromatography and then was used to raise rabbit antibodies specific for the delta antigen.

Animals↗
PubMed1988

Human immunodeficiency virus and hepatitis delta virus in homosexual men. A study of four cohorts.

The prevalence of hepatitis delta virus antibodies was determined in four cohorts of homosexual or bisexual men positive for hepatitis B surface antigen who were evaluated between April 1984 and April 1985. Antibodies to hepatitis delta virus were found in 16 of 106 men in Los Angeles (15.1%; 95% confidence interval [Cl], 8.3% to 21.9%); 6 of 64 men in San Francisco (9.4%; 95% Cl, 3.5% to 19.3%); 1 of 76 men in Pittsburgh (1.3%; 95% Cl, 0.03% to 7.1%); and 0 of 52 men in Chicago (0%; 95% Cl, 0% to 5.6%). From 44.0% to 65.4% of men negative for hepatitis delta virus and all men positive for hepatitis delta virus but one (P less than 0.0001) were positive for antibodies to human immunodeficiency virus (HIV). In multivariate analysis, infection with hepatitis delta virus was associated with intravenous drug use (adjusted odds ratio [OR] = 6.7, P less than 0.01), with sexual activity as measured by number of partners (adjusted OR = 8.4, p less than 0.01), and probably with rectal trauma (adjusted OR = 3.9, P = 0.17). As with HIV infection, prevalence of hepatitis delta virus infection in homosexual men differs by location and is most likely transmitted both sexually and parenterally.

HIV Seropositivity↗
PubMed1987

Replication of human hepatitis delta virus in primary cultures of woodchuck hepatocytes.

We obtained two lines of evidence that monolayer cultures of primary woodchuck hepatocytes support replication of the genome of human hepatitis delta virus (HDV). (i) From a Northern (RNA blot) analysis of the HDV-related RNA in infected cultures, both genomic and antigenomic 1.7-kilobase RNA species were detected at 11 days after infection. The ratio of genomic RNA to antigenomic RNA was 2:1 to 10:1, comparable to that previously reported in studies of experimentally infected chimpanzees and woodchucks. (ii) Replication in culture was also demonstrated by in situ hybridization with a strand-specific probe. Such studies showed that only a small fraction of the cultured cells supported replication and that in such cells the relative and absolute levels of the HDV RNAs were comparable to those in liver cells infected in vivo. Furthermore, as with the in vivo studies, the HDV RNAs were predominantly localized to the nucleus. In summary, we demonstrated that cultured cells supported both the early events of HDV adsorption and penetration and the intermediate events of genome replication.

Animals↗
PubMed1987

Inhibition of hepatitis delta virus (HDV) replication by lymphoblastoid human alpha interferon.

Lymphoblastoid interferon inhibited hepatitis delta virus (HDV) replication in four out of five HDV carriers with chronic active liver disease. Serum HDV-RNA was undetectable in three patients, but in one of these evidence of continuing intrahepatic HDV replication was present on biopsy one year after treatment. In the four cases which showed total or partial inhibition of HDV replication, there was a transient increase in transaminases during treatment, and in three this was followed by improvement. These effects lasted for longer than one year. The lysis of hepatocytes occurring on exposure to interferon may be related to the induction of 2-5A oligosynthetase which, in the presence of the dsRNA of HDV, activates endonucleases which destroy the rRNA of the infected cells.

Adult↗
PubMed1986

Structure and replication of the genome of the hepatitis delta virus.

The hepatitis delta virus can be found in the serum and liver of some hepatitis B virus patients. We now report that the RNA genome of serum-derived delta virus is single-stranded and circular. Livers of infected chimpanzees or woodchucks contained as many as 300,000 copies of genomic strand RNA per average cell, and at least some of this RNA had a circular conformation. Also present in the livers were RNA species complementary to the virion RNA. The genomic RNA was 5-22 times more abundant than this antigenomic strand. Some of the antigenomic RNA was complexed with genomic RNA, as evidenced by the fact that at least 34% of the antigenomic RNA was resistant to digestion with either RNase A in 0.3 M NaCl or S1 nuclease. Some of the antigenomic RNA was in a circular conformation. These and other findings showed that the structure and replication of hepatitis delta virus are in many ways similar to those of the previously described plant viroids, virusoids, and satellite RNAs.

Animals↗
PubMed1985

Double infections with hepatitis A and B viruses.

Ten (2.8%) asymptomatic carriers of HBsAg and four (1.1%) patients with acute hepatitis B virus (HBV) infection were detected among 356 adults with acute viral hepatitis A (HAV) consecutively admitted to the Athens Hospital for Infectious Diseases from May 1981 to March 1984. These patients did not differ in clinical, epidemiologic (except in age), biochemical or serologic characteristics from patients acutely infected with HAV alone. Transient suppression of the HBV replication and disappearance of the HBV DNA accompanied by seroconversion from HBeAg positive to anti-HBe positive were detected in one and two carriers respectively. The titer of non-class-specific anti-HBc was low (less than or equal to 10(-2)) in all cases. These data suggest that superinfection of HBsAg carriers with HAV does not cause more severe disease or influence adversely the course of chronic hepatitis B disease. However, accurate diagnosis of double infections is necessary for prognosis of the liver disease and appropriate management of the patient's environment. This is quite important in areas with a high prevalence of HBV infections, like Greece, where double infections are relatively common.

Acute Disease↗
PubMed1983

Hepatitis B virus replication and clinical outcome in carriers of HBsAg. Perspectives of treatment with DNA inhibitors.

HBV-DNA was measured by the spot hybridization technique in serial serum samples obtained from 47 HBsAg carriers followed up for a mean of 4 years. The levels of HBV-DNA were compared to the conventional HBV serology and immunopathology to determine the relation of active HBV replication to the outcome of hepatitis and the suitability of Italian HBsAg carriers for treatment with DNA inhibitors. HBV-DNA was found in 26 carriers (53%) and persisted with comparable serum levels in 24 of them throughout the follow up. The occurrence rate of an unfavorable outcome as determined by histological evidence of cirrhosis was 6% versus 44% (p less than 0.01) in carriers with active viral infection (greater than 1 ng/ml of HBV-DNA) and in patients with absent or low levels of viral DNA (less than 1 pg/ml), respectively. Progression of the liver disease could not be predicted on the basis of active HBV replication and was presumably related to factors other than synthesis of HBV. In many patients with inactive viral infection a primary pathogenic factor was the HBV-associated delta, an agent with a putative RNA genome against which DNA inhibitors have no rationale and possibly no effects. The majority of Italian carriers do not appear suitable for treatment with DNA inhibitors and they should be considered for a different therapy.

Adolescent↗