John L. Gerin

Structure, sequence and expression of the hepatitis delta (|[delta]|) viral genome

Biochemical and electron microscopic data indicate that the human hepatitis δ viral agent contains a covalently closed circular and single-stranded RNA genome that has certain similarities with viroid-like agents from plants. The sequence of the viral genome (1,678 nucleotides) has been determined and an open reading frame within the complementary strand has been shown to encode an antigen that binds specifically to antisera from patients with chronic hepatitis δ viral infections.

Type B hepatitis: the infectivity of blood positive for e antigen and DNA polymerase after accidental needlestick exposure.

To determine the relation between the presence of donor DNA polymerase and e antigen, and recipient hepatitis, we tested, under code, serums from a controlled trial of hepatitis B immune globulin used to treat individuals accidentally inoculated with HBs Ag-positive blood. All recipients lacked antibody to HBs Ag. In 29 of 31 donors, both polymerase and e were in perfect agreement; both demonstrated a highly significant correlation with recipient hepatitis (P less than 0.001). DNA polymerase/e-negative blood did not cause hepatitis. Blood containing polymerase or e antigen did not cause hepatitis in six of 31 and four of 18 recipients, respectively. Hepatitis did not correlate with transaminase or duration of antigenemia in the donor. Polymerase and e appear to be indicators of the relative infectivity of HBs Ag-positive serum, particularly after small-volume exposure. They may be important determinants in assessing infectivity of chronic carriers of HBs Ag and in evaluating efficacy of hepatitis B immune globulin and hepatitis B vaccines.

Natural history of acute hepatitis B surface antigen-positive hepatitis in Greek adults

We prospectively followed up 821 adults with acute viral hepatitis hospitalized at the Athens Hospital for Infectious Diseases between May 1981 and May 1983. Radioimmunoassays for the detection of serologic markers of hepatitis A virus, hepatitis B virus, and hepatitis delta virus, and molecular hybridization techniques for the detection of serum hepatitis B virus deoxyribonucleic acid and hepatitis delta virus ribonucleic acid were used. Based on the results of an enzyme immunoassay for the detection of immunoglobulin M antibody to hepatitis B core antigen (Corzyme-M), 563 cases were diagnosed as acute hepatitis B and 45 as acute hepatitis superimposed on hepatitis B surface antigen carriage. Development of the hepatitis B surface antigen carrier state was observed in only 1 (0.2%) of the 507 cases with acute hepatitis B that were followed. In contrast, hepatitis B surface antigen persisted in all the latter cases. Acute hepatitis superimposed on hepatitis B surface antigen carriage was attributed to hepatitis A virus superinfection in 2 (4.4%), hepatitis delta virus superinfection in 22 (48.9%), reactivation of chronic type B hepatitis in 12 (26.7%), seroconversion from hepatitis B e antigen-positive to anti-hepatitis B e antibody-positive in 2 (4.4%), presumed superinfection by non-A, non-B agent(s) in 6 (13.4%), and the first clinical manifestation of chronic active hepatitis in 1 (2.2%) case. These data show that acute clinical hepatitis B in adults seems to be a self-limited disease and rarely leads to the development of the carrier state in this epidemiologic setting and hepatitis delta virus superinfection and spontaneous reactivation of chronic hepatitis B are the principal causes of acute hepatitis superimposed in hepatitis B surface antigen carriers in an area with a moderately high prevalence of hepatitis B virus infections.

Recombinant vaccine against hepatitis E: dose response and protection against heterologous challenge

Thirty-two rhesus monkeys were used to evaluate the dose response of a recombinant HEV vaccine, and the efficacy of the vaccine based on the ORF2 protein of the Pakistani strain for pre- and post-exposure vaccination against intravenous challenge with homologous or heterologous virus was examined. Post-exposure vaccination did not protect animals against hepatitis. Although primates vaccinated twice with 50-microgram, 10-microgram, 2-microgram, or 0.4-microgram doses of the recombinant 55 kDa ORF-2 protein were infected, they were protected from hepatitis when they were challenged with very high doses of the homologous strain of HEV. Primates vaccinated twice with a 50 micrograms dose of the recombinant protein were protected from hepatitis after heterologous challenge with the Mexican strain, the strain of HEV most genetically distant from the Pakistani strain.

Hepatitis B subunit vaccine: a preliminary report of safety and efficacy tests in chimpanzees

The 22 nm spherical form of hepatitis B surface antigen was purified from the serum or plasma of chronic carriers of the antigen. Antigens of subtypes ayw and adr were individually prepared by isopycnic banding in cesium chloride followed by rate zonal separation in sucrose. Each preparation was stabilized with human serum albumin, and aliquots were inactivated with 1:2000 formalin at 37 C for 96 hours. The potency and immunogenicity of each preparation were determined: both antigenicity and immunogenicity were retained by the preparations following purification and inactivation. Seronegative chimpanzees were vaccinated with the antigen preparations. None of the vaccinated chimpanzees developed evidence of infection with hepatitis B virus during the follow-up period. Twenty-four weeks after vaccination vaccinated and control chimpanzees were inoculated with live hepatitis B virus. Control chimpanzees developed hepatitis associated with HBs Ag seven and nine weeks following challenge. In contrast, none of the chimpanzees vaccinated with HBs Ag developed HBs Ag or hepatitis. Thus, hepatitis B vaccine appeared to be safe and efficacious when tested in chimpanzees.

Hepatitis B Virus Infection in the Acquired Immunodeficiency Syndrome

Excerpt The acquired immunodeficiency syndrome has become a major phenomenon during the last 3 years. Recent data from several sources suggest that the syndrome may be a result of infection with a ...

Radioimmunoassay for the detection of the core of the Dane particle and antibody to it.

A radioimmunoassay for detecting the core of the Dane particle and antibody to it was developed. The core was detected in concentrates of Dane particles but not in preparations of purified 22-nm forms of hepatitis B antigen. Detergent treatment of Dane particles increased the detectability of the core. Antibody to the core appeared following acute type B hepatitis infection and could be consistently demonstrated in chronic carriers of hepatitis B antigen. Such antibody was found less frequently in patients with evidence of re-exposure to hepatitis B antigen; it could not be detected in pooled hepatitis B immune serum globulin.

Immunization with Surface Antigen Vaccine Alone and after Treatment with 1-(2-Fluoro-5-Methyl-β-l-Arabinofuranosyl)-Uracil (l-FMAU) Breaks Humoral and Cell-Mediated Immune Tolerance in Chronic Woodchuck Hepatitis Virus Infection

ABSTRACT Woodchucks chronically infected with the woodchuck hepatitis virus (WHV) were treated with the antiviral drug 1-(2-fluoro-5-methyl-β-l-arabinofuranosyl)-uracil (l-FMAU) or placebo for 32 weeks. Half the woodchucks in each group then received four injections of surface antigen vaccine during the next 16 weeks. Vaccination alone elicited a low-level antibody response to surface antigen in most carriers but did not affect serum WHV DNA and surface antigen. Carriers treated first with l-FMAU to reduce serum WHV DNA and surface antigen and then vaccinated had a similar low-level antibody response to surface antigen. Following vaccinations, cell-mediated immunity to surface antigen was demonstrated in both groups, independent of serum viral and antigen load, but was significantly enhanced in woodchucks treated with l-FMAU and was broadened to include other viral antigens (core, e, and x antigens and selected core peptides). Cell-mediated immunity and antibody responses to surface antigen were observed after drug discontinuation in half of the carriers that received l-FMAU alone. Surface antigen vaccine alone or in combination with drug broke humoral and cell-mediated immune tolerance in chronic WHV infection, but the combination with drug was more effective. This suggested that a high viral and antigen load in carriers is important in maintaining immunologic tolerance during chronicity. The humoral and cellular immunity associated with the combination of l-FMAU and vaccine resembled that observed in self-limited WHV infection. Such combination therapy represents a potentially useful approach to the control of chronic hepatitis B virus infection in humans.

Deficiencies in the Acute-Phase Cell-Mediated Immune Response to Viral Antigens Are Associated with Development of Chronic Woodchuck Hepatitis Virus Infection following Neonatal Inoculation

ABSTRACT In vitro proliferation of peripheral blood mononuclear cells was used to measure virus-specific cell-mediated immunity (vCMI) following neonatal woodchuck hepatitis virus (WHV) infection. Fifteen neonates were inoculated with the W8 strain of WHV. In 11, infection was resolved, and 4 became chronic carriers. Nineteen neonates were inoculated with the W7 strain and all became chronic carriers. Seven age-matched uninfected woodchucks served as controls. Virologic and vCMI profiles among the W8 and W7 infections were compared and related to the outcome of infection. Resolving woodchucks had robust, acute-phase vCMI to WHV antigens (core, surface, and x) and to several nonoverlapping core peptides. The acute-phase vCMI was associated temporally with the clearance of viral DNA and of surface antigen from serum at 14 to 22 weeks postinfection. In contrast, in approximately half of the W8 and W7 infections that progressed to chronicity, no significant acute-phase vCMI was detected. In the remaining carriers, acute-phase vCMI was observed, but it was less frequent and incomplete compared to that of resolved woodchucks. Serum viral load developed less rapidly in those carriers that had evidence of acute-phase vCMI, but it was still increased compared to that of resolving woodchucks. Thus, vigorous and multispecific acute-phase vCMI was associated with resolution of neonatal WHV infection. Absent or incomplete acute-phase vCMI was associated with the progression to chronic infection. By analogy, these results suggest that the onset of chronic hepatitis B virus (HBV) infection in humans may be associated with deficiencies in the primary T-cell response to acute HBV infection.

Immunogenicity and protective efficacy of a vaccine prepared from 53 kDa truncated hepatitis E virus capsid protein expressed in insect cells

Hepatitis E virus (HEV) is an enterically transmitted virus that causes acute hepatitis. Expression of recombinant HEV capsid protein in insect cells results in two major proteolytically-processed products of 56 and 53kDa which consist of amino acids (aa) 112-607 and 112-578, respectively. The only neutralization epitope identified to date is located at least partially between amino acids 578 and 607 meaning it should be present only in the 56 and not in the 53kDa protein. Previously, it was shown that vaccination with the 56kDa protein greatly reduced virus shedding and protected Rhesus monkeys from hepatitis E when challenged with a high intravenous dose of homologous or heterologous HEV. To evaluate the immunogenicity and protective efficacy of the 53kDa protein, we vaccinated Rhesus monkeys with this protein and challenged them with a high or low dose of homologous virus. Vaccination with the 53kDa protein greatly reduced virus shedding but did not protect against hepatitis following the high dose challenge. Virus was not detected in the vaccinated animals following the low dose challenge, suggesting that sterilizing immunity may have been achieved.