Search

We describe 2 preterm neonates with transient hepatitis B surface (HBs) antigenemia detected after Hepatitis B vaccination. Repeat serology in both cases tested negative for hepatitis B surface antigen, confirming transient HBs antigenemia. The duration of transient HBs antigenemia affirms current literature in the pediatric population.

We compared the kinetics and magnitude of hepatitis B virus (HBV) infection in hepatitis C virus (HCV)-naive and chronically HCV-infected chimpanzees in whose livers type I interferon-stimulated gene (ISG) expression is strongly induced. HBV infection was delayed and attenuated in the HCV-infected animals, and the number of HBV-infected hepatocytes was drastically reduced. These results suggest that establishment of HBV infection and its replication space is limited by the antiviral effects of type I interferon in the chronically HCV-infected liver.

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.

Viral clearance during hepatitis B virus (HBV) infection has been thought to reflect the destruction of infected hepatocytes by CD8(+) T lymphocytes. However, in this study, HBV DNA was shown to largely disappear from the liver and the blood of acutely infected chimpanzees long before the peak of T cell infiltration and most of the liver disease. These results demonstrate that noncytopathic antiviral mechanisms contribute to viral clearance during acute viral hepatitis by purging HBV replicative intermediates from the cytoplasm and covalently closed circular viral DNA from the nucleus of infected cells.

Using an in vitro peptide stimulation strategy, two chimpanzees that were acutely infected by the hepatitis B virus (HBV) produced peripheral blood CTL responses to several HBV-encoded epitopes that are known to be recognized by class I-restricted CTL in acutely infected humans. One animal responded to three HBV peptides that, in humans, are restricted by HLA-A2; the other animal responded to three peptides that are restricted by HLA-B35 and HLA-B51, members of the HLA-B7 supertype in man. The peptides recognized by each chimp corresponded with the ability of its class I molecules to bind peptides containing the HLA-A2 and HLA-B7 supermotifs. Similar, apparently class I-restricted CTL responses to some of these peptides were also detected in occasional HBV-uninfected chimps. These results demonstrate that the CTL repertoire overlaps in humans and chimps and that the HLA-A2 and HLA-B7 supertypes extend to the chimpanzee. Based on these results, the immunogenicity and efficacy of vaccines designed to induce CTL responses to human HLA-restricted viral epitopes may be testable in chimpanzees.

In vivo transfection of Eastern woodchucks (Marmota monax) with recombinant woodchuck hepatitis virus (WHV) DNA is effective in inducing virus infection for the study of replication, pathogenicity, and oncogenicity of wild-type and mutated WHV. The one drawback to this procedure is the need for preparation of large amounts of WHV DNA. Reduction of the amount of WHV DNA in the transfection protocol necessary to induce infection would save considerable time and resources. Therefore, we conducted a titration of WHV DNA, ranging from 50 micrograms to 50 pg of DNA, in adult woodchucks to determine the minimum infectious dose of recombinant WHV DNA. As little as 50 ng of transfected WHV DNA induced productive infection in adult woodchucks. Thus, transfection with large amounts of recombinant WHV DNA appears to be unnecessary.

Hepatitis B virus (HBV) variants with amino acid mutations in the a epitope of the major surface protein have been identified, and questions have been raised regarding their biologic properties. Dilutions of serum that contained the first such described HBV mutant, with an Arg-for-Gly substitution at codon 145 of the S gene, were inoculated into 6 seronegative chimpanzees. Five of the animals developed serologic and/or biochemical evidence of hepatitis B. A polymerase chain reaction-based assay that discriminated between the wild type and mutant viral genomes revealed that a pure population of the mutant genome was present in the 10(-6) and 10(-7) dilutions of the index serum, resulting in infection of the chimpanzees receiving these dilutions only with the mutant virus. A clone of the mutant virus replicated normally following transfection in vitro. Thus, this HBV surface gene mutant is viable, infectious, and pathogenic in chimpanzees.

Vaccination of two chimpanzees against hepatitis B virus (HBV) by intramuscular injection of plasmid DNA encoding the major and middle HBV envelope proteins induced group-, subtype- and preS2-specific antibodies. These were initially of IgM isotype, and then they were of IgG (predominantly IgGl) isotype. The chimpanzee injected with 2 mg of DNA attained >100 milli-international units/ml of anti-HBs antibody after one injection and 14,000 milli-international units/ml after four injections. A smaller dose (400 microg) induced lower and transient titers, but a strong anamnestic response occurred 1 year later. Comparison with responses in 23 chimpanzees receiving various antigen-based HBV vaccines suggests that the DNA approach is promising for prophylactic immunization against HBV.

Perinatal transmission of hepatitis B virus (HBV) contributes to the high prevalence of chronic infection in China and many other countries. In a placebo-controlled trial among 166 infants, the 12-month efficacy of active postexposure prophylaxis to prevent chronic perinatal HBV infection varied by vaccine (range, 45%-89%). In a 5-year follow-up study, 2 additional infants became chronically infected with HBV, and the efficacy of active prophylaxis was estimated to be 38% and 72% for the two vaccines at 5 years. In addition, 80% of immunized infants continued to have protective levels of antibody at the end of 5 years. However, among 27 infants who received passive-active immunoprophylaxis with high-dose hepatitis B immune globulin, only 60% (11/19) had protective antibody levels. These data indicate that active postexposure immunization initiated soon after birth continues to provide protection during early childhood when there is a high risk of chronic HBV infection.

Hepatitis B virus (HBV) with an in-frame stop codon within the pre-core region of the virus genome caused fulminant hepatitis in two individuals. Serum from a chronically infected patient who was the source of the virus was inoculated into three chimpanzees at dilutions of 10(-1), 10(-3), and 10(-7). All three chimpanzees developed acute hepatitis B with relatively high peak values of liver enzymes in their serum. The complete nucleotide sequence of virus DNA recovered from the chimpanzee serum by enzymatic amplification was identical with that from the human serum. By comparing the sequence of this strain (HT) with that of 32 published HBV genomes, changes in nucleotides and predicted amino acids that were rarely or never found in other HBV isolates were identified. Thirteen such nucleotides were found within the cis-acting regulatory elements, of which 6 were within the enhancer II-core promoter region. Twenty-four rare or unique changes in amino acids were found in open reading frames, of which 15 occurred in the region that spanned the 3' half of the X gene, through the pre-core/core gene, to the 5' end of the polymerase gene. Thus, an HBV pre-core stop mutant implicated in fulminant hepatitis is highly infectious, induces severe hepatitis in chimpanzees, and possesses significant genetic variation from reported HBV isolates.

The protective efficacy of a human monoclonal antibody directed against the a determinant of hepatitis B virus (HBV) surface antigen was studied in a chimpanzee. A single high dose of 5 mg/kg (body weight) of monoclonal antibody SDZ OST 577 was intravenously administered to a chimpanzee, followed by intravenous challenge with 10(3.5) chimpanzee infectious doses of a wild-type HBV, the MS-2 strain (ayw subtype). The passively acquired antibody to HBV surface antigen could be detected for 40 weeks. Serum HBV DNA tested by a "nested" polymerase chain reaction assay was negative through the 36th week after virus challenge but became positive by the 38th week. The chimpanzee subsequently developed acute hepatitis B approximately 1 year after challenge. The nucleotide sequence of the a determinant of the surface gene of the replicated virus was identical with that of the inoculated wild-type virus. Thus, a human monoclonal antibody directed against the a determinant of HBV surface antigen delayed but did not prevent experimental infection of HBV and hepatitis in the chimpanzee. Our results indicate an incomplete ability of this antibody to protect against HBV infection in vivo after a single infusion.

Background: Infections with hepatitis B virus (HBV), hepatitis C virus (HCV), and the human immunodeficiency virus type 1 (HIV-1) are common in inner-city populations, but their frequency and interrelations are not well established., Methods: During a six-week period, excess serum samples were collected, along with information on risk factors, from all adult patients presenting to an inner-city emergency department. The samples were assayed for hepatitis B surface antigen (HBsAg) and antibodies to HCV and HIV-1., Results: Of the 2523 patients tested, 612 (24 percent) were infected with at least one of the three viruses. Five percent were seropositive for HBV, 18 percent for HCV, and 6 percent for HIV-1. HCV was found in 145 of the 175 intravenous drug users (83 percent), 36 of the 171 transfusion recipients (21 percent), and 5 of the 24 homosexual men (21 percent). Among black men 35 to 44 years of age, the seroprevalence of HCV was 51 percent. HBsAg was present in 9 percent of those whose only identifiable risk was possible heterosexual exposure. At least one viral marker was found in about 30 percent of the patients who were actively bleeding or in whom procedures were performed. Testing for HIV-1 alone would have failed to identify 87 percent of the patients infected with HBV and 80 percent of those infected with HCV., Conclusions: In a population of patients in an inner-city emergency room, HBV, HCV, and HIV-1 are all highly prevalent. However, routine screening for HIV-1 alone would identify only a small fraction of the patients who pose risks of severe viral infections, including HBV and HCV, to providers.

Bedbugs (Cimex lectularius L.) were fed on an infective blood-hepatitis B virus (HBV) mixture. Further bedbugs and tampan ticks (Ornithodoros moubata [Murray]) were fed on HBV-carrier chimpanzees. After a 10-13 day interval for oviposition, tests done on samples of individual arthropods showed that 53-85% of the bugs were HBsAg-positive and none HBeAg-positive, while 100% of the ticks were HBsAg-positive and 88% HBeAg-positive. The remaining arthropods were fed on 3 susceptible chimpanzees, which had failed to develop HBV infection after 11 months, indicating no transmission had occurred. Subsequently the presence of viable virus in the original infective meals was confirmed by inoculation of the relevant donor sera directly into the 3 still susceptible chimpanzees. HBV infections quickly followed in each animal. It is concluded that, while mechanical transmission of HBV is most unlikely after a 10-13-day interval between feedings in bedbugs and tampans, it is still possible that mechanical transmission between humans might occur during interrupted feeds.

The 19S and 7-8S forms of IgM antibody to hepatitis B core antigen (IgM anti-HBc) were separated by rate-zonal centrifugation from the serum of 20 Greek hepatitis B surface antigen (HBsAg) carriers with a superimposed acute icteric hepatitis positive for IgM anti-HBc by a radioimmunoassay. Serological markers of hepatitis A virus (HAV), hepatitis B virus (HBV) and hepatitis D virus (HDV) infections were detected with radioimmunoassays and serum HBV DNA was detected with molecular hybridization techniques. Eighteen of the 20 carriers showed a predominance of one or the other form of IgM anti-HBc. Low molecular weight (7-8S) IgM anti-HBc was observed more frequently in HDV superinfection (5/9) and was related to a low mortality (1/9). In contrast, 19S IgM anti-HBc was observed more frequently in reactivation of chronic hepatitis B (6/9) and was related to a high mortality (5/9). These preliminary data show that in HBsAg carriers with a superimposed acute icteric hepatitis, predominance of 19S IgM anti-HBc is frequently associated with a severe clinical course; the opposite is true for predominance of 7-8S IgM anti-HBc.

Standard methods of virus DNA detection using the polymerase chain reaction can be time consuming and can involve multiple steps in which contamination with exogenous DNA can occur. Therefore, we developed a simplified method for detecting hepatitis B virus DNA in serum. The main advantages of this method are that it can be performed rapidly, consists of only several steps, and has a false positive rate of less than 0.1% in our laboratory. In testing serial samples from five chimpanzees experimentally infected with hepatitis B virus, we found that hepatitis B virus DNA was detected 2-3 weeks before the appearance of hepatitis B surface antigen, and it continued to be detectable 1-3 weeks after the production of antibody to hepatitis B surface antigen. In testing serum from 84 human patients, we found hepatitis B virus DNA in all patients who had hepatitis B surface antigen and hepatitis B e antigen in serum and in 64% of the patients with hepatitis B surface antigen with antibody to hepatitis B e antigen in serum. Also, 3 out of 11 patients who were chronic hepatitis B carriers and who subsequently lost hepatitis B surface antigen were found to test positive for hepatitis B virus in serum. In contrast, all patients who lost hepatitis B surface antigen after acute hepatitis B virus infection or those classified as having non-A, non-B hepatitis tested negative for hepatitis B virus DNA. Thus, the modified PCR technique is a sensitive and rapid method for detecting hepatitis B virus DNA-containing virions in serum.

The hepatitis B virus-associated beta antigen was found in the serum of experimentally infected chimpanzee as an internal component of a discrete subpopulation of hepatitis B surface antigen (HBsAg) particles. The 35- to 37-nm particles banded in CsCl at 1.24-1.25 g/cm3 and sedimented with a mobility intermediate between that of the hepatitis B virion and that of the 22-nm form of HBsAg. The particles contained only indistinct internal structure by electron microscopy and were not unique to delta agent infection, similar particles without delta-antigen activity being observed in the preinfection serum of HBsAg carrier chimpanzees. A small RNA (Mr, 5 X 10(5)) was temporally associated with delta antigen in the serum of infected chimpanzees and copurified with the delta-antigen-associated particles. This RNA is smaller than the genomes of known RNA viruses but larger than the viroids of higher plants.

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.

Serological investigations for hepatitis B surface and e antigen, antibody to hepatitis B surface, core and e antigen and antibody to hepatitis A virus were carried out in 22 patients with fulminant hepatitis admitted to Medical Department A, Rigshospitalet, Copenhagen, in 1970-77. Nine patients had hepatitis type B and four type A. One patient had evidence of both type A and B infection, whereas the remaining eight patients showed no evidence of type A or B infection. Two of these had been treated with disulfiram and a drug aetiology could not be excluded, but in six patients no known cause of fulminant hepatitis could be determined and these patients were classified as having hepatitis type non-A non-B. The survival rate was not statistically different for patients having type A, B, or non-A non-B hepatitis.

Although many primate species have been inoculated with the agents of human hepatitis A, B, and non-A, non-B, only a small number of species have been shown to be susceptible, and only the chimpanzee (Pan troglodytes) has been shown to be reproducibly susceptible to all three types of human hepatitis. Infectious inocula containing each agent have been identified in different laboratories and the end-point titers of infectivity determined, in most cases by inoculation of chimpanzees. These inocula and the nonhuman primate models have permitted investigators to study the inactivation of these agents and to evaluate passive and active immunization against the agents.

Hepatitis B virus (HBV) is an important human pathogen responsible for over 200 million cases of chronic infection, many of which progress to hepatocellular carcinoma. Although HBV cannot be propagated in tissue culture, highly effective subunit vaccines obtained from the plasma of chronically infected patients have been developed and licensed. Such vaccines are safe but their expense and limited quantities make them unavailable to most Third World countries. Other approaches to vaccine construction, including purification of the HBV surface antigen (HBsAg) from genetically engineered eukaryotic cells and the synthesis of peptides predicted from the nucleotide sequence of the HBsAg gene, are still under evaluation. Another potential application of recombinant DNA technology to vaccine development is the use of live virus vectors to express foreign genes. An infectious vaccinia virus recombinant that expressed the HBsAg in animal cells and which stimulated the production of antibody to HBsAg (anti-HBs) in rabbits represented a novel candidate vaccine of this class. As a continuation of our earlier study, we now present evidence that chimpanzees vaccinated with a live recombinant vaccinia virus protected against hepatitis following challenge with HBV.

Thirty-four chimpanzees were inoculated with sera containing the adw, ayw, adr, or ayr subtype of hepatitis B surface antigen (HBs Ag). Twenty-nine of the animals became infected with hepatitis B virus, and in every instance the subtype of HBs Ag in the infected animal was the same as the subtype in the inoculum. Infectivity titers were established for the adw and ayw inocula. The patterns of serologic events varied in the infected animals but included most of the typical patterns of serologic change seen in human cases of type B hepatitis. Mild disease, manifested by elevated concentrations of serum enzymes and changes detected by liver biopsy, occurred in 23 of the 29 infected animals.

Three hundred and twenty drug-free former narcotic addicts were studied with regard to persistence of abnormalities of liver function and morphology, and their relation to hepatitis B infection. Hepatitis B antibody was present in 52.4 per cent, while HBs antigen was detected in only 6 per cent. Transaminase abnormalities, initially present in 39 per cent, were found in 22 per cent six months after cessation of drug abuse. Abnormalities tended to persist thereafter, although there was some continued return to normal levels. Liver biopsy findings of chronic persistent and aggressive hepatitis correlated with persistence of HBs antigenemia and transaminase elevation. Follow-up liver biopsies in seven subjects showed decreased inflammatory reaction in five. None showed progressive liver disease. We conclude that: (1) 15 to 20 per cent of former narcotics addicts have chronic persistent hepatitis or chronic aggressive hepatitis after cessation of drug absuse for six months or more; (2) serologic evidence of exposure to HBs antigen is frequent, and rapidly develops after the start of needle use; (3) although histologic ad chemical abnormalities usually persist, progression did not occur, and some individuals demonstrated spontaneous improvement.

Four chronic hepatitis B virus (HBV) carrier chimpanzees, which had apparently cleared hepatitis D virus (HDV) after a first experimental challenge with HDV, were reinoculated with a homologous strain of HDV. All animals had reappearance of low levels of serum HDV RNA and transient, mild alanine aminotransferase (ALT) elevations, which in two cases correlated with HDV RNA positivity. Plasmas obtained from two chimpanzees after rechallenge were inoculated into two other chronic HBV carrier animals that had recovered from a previous HDV infection. A similar reappearance of HDV RNA in serum (without ALT elevation) was noticed. These same plasmas, however, when inoculated into a chronic HBV carrier chimpanzee never exposed to HDV caused a severe acute hepatitis D. Rechallenge with HDV in chimpanzees apparently recovered from a first HDV infection resulted in the reappearance of HDV replication, sometimes associated with hepatitis. This can be interpreted as reinfection with HDV, but other explanations are possible. Although the serum level of HDV RNA observed after rechallenge with HDV is low, its transmission to individuals susceptible to HDV infection can result in severe acute hepatitis D.

In this paper we report on anti-HBc-titers, HBcAg, DNApolymerase activity in the serum and intracellular HBsAg in healthy HBsAg-carriers and patients with HBsAg-positive inflammatory liver diseases. 32/44 patients with acure virus-B-hepatitis were negative for anti-HBc in the first week of the disease. Anti-HBc-titers in healthy HBsAg-carriers varied between 1:10 and 1:32,000 (medium titer 1:4,000). In HBsAg-positive CAH we found a medium titer between 1:32,000 and 1:64,000, in cases with CPH of about 1:16,000. All autoimmune type CAH showed anti-HBc-titers less than 1:10. By immunofluorescence we could demonstrate in a group of 71 asymptomatic HBsAg-carriers in none of the healthy HBsAg-carriers HBcAg in the liver cell nuclei. In contrast HBcAg could only be found in 4/5 HBsAg positive CAH- and 6/9 CPH patients. No elevated DNApolymerase activity could be demonstrated in healthy HBsAg-carriers. Out of 44 patients with virus-B-hepatitis only 3 showed elevated DNApolymerase activity. On the other hand DNApolymerase elevation was demonstrable in 17/37 cases with CAH and 9/15 with CPH. The investigations showed a strong correlation between the demonstration of HBcAg in the serum and the DNApolymerase activity. The characteristic findings enabled us to differentiate between "healthy" HBsAg-carriers and HBsAg-carriers with inflammatory liver diseases.

Hepatitis B is a serious disease of global significance. In developing countries, hepatitis B virus (HBV) infection and its sequelae rank among the public health problems of highest priority. Infants born to mothers who are chronic carriers of HBV are at particularly high risk of acquiring infection and becoming chronic HBV carriers. The efficacy of hepatitis B vaccine alone in preventing the transmission of HBV to infants born to HBV carrier mothers was determined in a double-blind placebo-controlled trial. Infants received plasma-derived vaccine at birth, 1 month, and 6 months of age. Of 180 infants born to hepatitis B surface antigen (HBsAg)-positive mothers, equal numbers received National Institute of Allergy and Infectious Disease (NIAID) vaccine, Beijing Institute of Vaccine and Serum (BIVS) vaccine, and placebo. The cumulative seroconversion to the vaccines at 1 year of age was 95% and 75%, respectively. Vaccine efficacy as measured by the prevention of HBsAg-positive events was 88% for the NIAID vaccine and 51% for the BIVS vaccine. Vaccine efficacy was similar among infants born to hepatitis Be antigen-positive mothers. Because of the low efficacy of the BIVS vaccine, an additional group of 28 infants was given vaccine and hepatitis B immune globulin at birth. The resulting efficacy was 83%. The results of this trial indicate that hepatitis B vaccine alone can substantially reduce perinatally acquired HBV infection and the resulting chronic carrier state.

We have reported that clonal cells derived from Hep G2 cells transfected with a plasmid containing hepatitis B virus (HBV) DNA secrete spherical and filamentous forms of hepatitis B surface antigen (HBsAg), core particles, and virions into the culture medium. Here we describe the development of typical hepatitis in two chimpanzees following intravenous inoculation with the medium in which the transfected cells had grown. The liver biopsies from these animals showed characteristic lesions in parenchyma and portal tracts, more conspicuous at an earlier time in the chimpanzee that had received a greater number of virions. The amount of HBsAg in the serum of one infected chimpanzee increased with time after the initial inoculation and then decreased concomitantly with the appearance of antibodies against HBsAg and core antigens. HBsAg remained detectable in the other animal throughout the course of the experiment. The levels of hepatitis B "e" antigen in both animals peaked at week 5, signifying the acute phase of the infection. The activities of serum enzymes that are markers for necroinflammation also increased. The hepatitis HBsAg subtype of the virions isolated from the patient whose DNA was cloned and then used for transfection of the Hep G2 cells was the same as that found in the chimpanzees. Furthermore, the restriction enzyme analysis of the viral DNA isolated from the chimpanzees was identical to the cloned DNA. Thus, HBV DNA-transfected Hep G2 cells can support the replication of virions that, in turn, produce hepatitis in chimpanzees.

Data obtained concerning Hepatitis B as a possible couse of Down's syndrome, neonatal hepatitis, and the occurrence of Hepatitis A and B in institutionalized Down's syndrome and matched non-Down's syndrome retarded patients was summarized. The results of our studies indicated that Hepatitis B infection during pregnancy was not related to the genetic changes associated with Down's syndrome. It was further indicated that in institutionalized patients the incidence of Hepatitis B infection in both Down's syndrome and other mentally retarded patients was similar. Within the institition we studied, the incidence of Hepatitis B varied among wards. This ward variation seemed to be related to age at time of institutionalization and degree of mental retardation. Those patients with most retardation and those institutionalized at an early age were placed on wards with highest incidence of Hepatitis B antigenemia.

As a model of virus-induced disease, the WHV/woodchuck system is at an early stage of development; yet, much progress has been made and there now exists considerable evidence that WHV causes serious liver disease with major parallels to HBV infection of man. The relatively short interval (4-5 yrs) from infection to end-stage disease in this model provides unique opportunities for definition of the natural history of HBV disease and the evaluation of various intervention strategies (e.g., vaccine prophylaxis and anti-viral therapy). Such studies are currently in progress in a number of laboratories.

The epidemiology of infections with hepatitis B virus was studied by measurement of serum antibodies to hepatitis B surface antigen (HBS Ag) with the radioimmuno-precipitation test. Prospective studies of household contacts of HBS Ag-positive patients with acute hepatitis demonstrated that four of 41 children and one of 60 adults experienced anicteric seroconversions. Two of the 60 adults also had mild icteric hepatitis and became chronically antigenemic. Neither HBS Ag nor antibody to HBS Ag was detected in follow-up blood samples from 85 seronegative contacts of HBS Ag-negative patients with hepatitis, although seven icteric secondary cases were identified. Household contacts of HBS Ag carriers frequently had serologic evidence of exposure to hepatitis B virus (44% of adults), but the remainder had neither detectable antigen nor antibody.

Twenty-two patients who had an episode of transfusion-associated hepatitis not positive for hepatitis B antigen were examined for development of antibody to heaptitis A and B antigens, cytomegalovirus and Epstein-Barr virus. Antibody response to the 27-nm virus-like hepatitis A antigen was measured by immune electron microscopy. In none of the 22 patients studied did serologic evidence of infection with hepatitis A virus develop during the study period. Nine of the 22 patients had antibody responses to cytomegalovirus, but it was difficult to relate these seroconversions to their hepatitis. In addition, all 22 patients had pre-existing antibody to the Epstein-Barr virus. It seems likely that at least a proportion of such antigen-negative transfusion-associated hepatitis is caused by other infectious agents, not yet identified.

Inoculation of hepatitis B surface antigen (HBsAg)-positive sera from patients with chronic liver disease and intrahepatic delta (delta) into chimpanzees susceptible to infection with hepatitis B virus (HBV) resulted in type B hepatitis and delta markers (delta antigen and antibody to delta) in recipient animals. A dilution (10(-8)) of serum induced type B hepatitis without delta markers in another HBV-susceptible animal. HBV infection and delta markers did not develop in animals with preexisting titers of antibody of HBsAg. In chimpanzees with circulating HBsAg at the time of inoculation, synthesis of delta occurred earlier and its extent and duration were greater than in animals previously unexposed to HBV; coincident with synthesis of delta, hepatitis occurred in chronic HBsAg carriers, and synthesis of preexisting HBV gene products (HBsAg and hepatitis B core antigen) was diminished. Delta appears to be a marker of a transmissible pathogenic agent, either an HBV variant or another agent that requires the helper functions of HBV, that is defective and interferes with HBV replication.

A microtitre solid-phase blocking radioimmunoassay (RIA) for antibody to the hepatitis B virus (HBV)-associated delta antigen was specific and detected anti-delta antibody at dilutions of serum of up to 10(6). Analysis of sera from HBsAg-negative subjects and different categories of HBsAg carriers from different regions confirmed the association of anti-delta antibody with HBV infection. Anti-delta antibody was detected in persistently high titres in 19.1% and 2.6% of sera from patients with chronic hepatitis and symptomatic chronic carriers, respectively, and was not detected in the sera of HBsAg-negative controls. Anti-delta antibody appeared transiently and in low titres (less than 1:500) in 4.8% of sera from patients with acute type B hepatitis. The presence and persistence of anti-delta antibody seem to be associated with chronic HBV infection and the development of progressive liver damage.

Experimental hepatitis B vaccines have recently been developed and are undergoing preliminary evaluation. These vaccines are unique in that they are prepared from viral antigen purified from the plasmas of human chronic carriers because hepatitis B virus has not been cultivated in vitro. They appear to be safe and antigenic, but care must be exercised in their evaluation because of the potential risks inherent in all vaccines.

The occurrence and pathogenetic role of intrahepatic deposits of immunoglobulins in experimental viral infection have been evaluated by determining with immunofluorescence their capacity to fix complement in vitro [in vitro complement fixation (VCF)]. Liver biopsies from chimpanzees chronically or acutely infected with hepatitis B virus or the hepatitis B surface antigen (HBsAg)-associated delta agent were used in the study. VCF was observed in each animal expressing hepatitis B core antigen (HBcAg) or delta antigen in the liver and concurrently circulating the homologous antibody in the blood. In acutely infected animals, VCF appeared at the same time that the homologous serum antibody appeared, and the intensity of VCF staining was proportional to the antibody titer in the serum. In animals expressing sequentially the HBcAg/antibody system and then delta antigen and antibody to delta, VCF was first observed in HBcAg-containing nuclei and then in nuclei expressing delta antigen. There was no relationship between VCF and intrahepatic expression of HBsAg or serologic expression of hepatitis B e antigen (HBeAg). A positive VCF reaction appears related to the formation of intrahepatic immune complexes between HBcAg or delta antigen and the homologous antibody. Although acute hepatitis developed in parallel with the occurrence of VCF in two animals, strong VCF fluorescence was also observed in each of the asymptomatic carriers of HBsAg, and, in one of them, preexisting VCF staining of HBcAg disappeared in parallel with development of acute hepatitis. In experimentally infected chimpanzees, the finding in liver biopsies of immune complexes detectable by VCF appears to be a common epiphenomenon without pathogenic significance.

The authors tested, by molecular hybridization, for hepatitis B virus DNA in serum specimens of 182 asymptomatic hepatitis B surface antigen (HBsAg) Greek carriers who were heterosexual partners of patients with acute hepatitis B (group A: 96 cases) or healthy subjects who were susceptible to hepatitis B (group B: 86 cases). The mean age (34.1 +/- 10.4 vs. 33.9 +/- 8.4 years) and the mean duration of sexual contact (6.9 +/- 8.9 vs. 7.2 +/- 6.3 years) were similar in the two groups of carriers. Hepatitis B virus DNA was detected significantly more frequently in group A than in group B (59.4% vs. 11.6%, p less than 0.001). In particular, in group A, hepatitis B virus DNA was detected in 96.9% of hepatitis B e antigen (HBeAg)-positive and 41% of antibody to HBeAg (anti-HBe)-positive carriers. In contrast, in group B, hepatitis B virus DNA was identified in only 10.8% of anti-HBe-positive carriers (p less than 0.001). These differences were especially significant in the young and middle-aged carriers (16-49 years old) and during the first four years of sexual contact. These data suggest that 1) there is a positive correlation between the presence of hepatitis B virus DNA in serum and the epidemiologic evidence of sexual transmission of hepatitis B virus, 2) hepatitis B virus DNA is a better indicator of infectivity than HBeAg/anti-HBe, and 3) the detection of hepatitis B virus DNA in serum probably identified carriers with high infectivity and potentially higher risk of transmitting hepatitis B virus to their sexual partners.

To assess the infectivity of hepatitis B surface antigen (HBsAg)-containing body fluids other than blood, chimpanzees were inoculated intravenously with saliva and semen obtained from HBsAg-positive individuals implicated in non-percutaneous transmission of hepatitis B. Saliva and semen samples were negative for occult blood. The titer of HBsAg in saliva was on the average only 1/3,000 that of the corresponding serum. One chimpanzee, inoculated sequentially with saliva from three individuals, developed HBsAg at 9 weeks and serum glutamic pyruvic transaminase elevation at 13 weeks after injection. HBsAg persisted for 15 weeks. This animal also developed e antigen, anti-core antibody, and anti-surface antibody. Liver biopsies showed acute hepatitis that subsequently resolved. A second chimpanzee, inoculated with HBsAg-positive semen, developed HBsAg and elevated serum glutamic pyruvic transaminase 4 weeks after inoculation and then died suddenly without explanation. HBsAg was positive in two consecutive samples and was confirmed by specific neutralization. Autopsy did not reveal evidence of hepatitis. This study demonstrates that HBsAg-positive saliva and, probably, semen contain infectious virus and suggests that saliva and/or semen may serve as important mechanisms in the transmission of type B hepatitis.

The exclusion of commercial and hepatitis B surface antigen (HBs Ag)-positive donors, as measured by counterelectrophoresis, has markedly reduced the frequency of post-transfusion hepatitis (PTH). A further, significant reduction in type-B PTH can be achieved by prescreening donors for HBs Ag by solid-phase radioimmunoassay (RIA); When a voluntary donor population, pretreated by RIA, is used, approximately 90 per cent of residual hepatitis is serologically unrelated to either the type-A or type-B hepatitis viruses. Similarly, cytomegalovirus and the Epstein-Barr virus are not serologically implicated in "non-A, non-B" hepatitis. Additional human hepatitis virus(es) may exist.

Eleven male fulminant hepatitis (FH) patients (mean age: 47.7 +/- 16 years) positive for hepatitis B surface antigen (HBsAg) but negative for IgM antibody to hepatitis B core antigen (IgM anti-HBc) were admitted consecutively to the Athens Hospital for Infectious Diseases between May 1981 and November 1983. Because of the absence of IgM anti-HBc, determined by an enzyme immunoassay, these patients were considered to be HBsAg carriers with a superimposed acute hepatitis. Three of the 11 patients received immunosuppressive chemotherapy during the six months before the onset of the acute hepatitis. None of the patients was homosexual or a drug addict. Infection with hepatitis A virus (HAV), hepatitis B virus (HBV), or hepatitis delta virus (HDV) was detected with serologic markers and/or molecular hybridization techniques. Fulminant hepatitis was attributed to spontaneous reactivation of chronic hepatitis B in four patients, chemotherapy-induced reactivation of chronic hepatitis B in three patients, HDV superinfection in one patient and possible superinfection by non-A, non-B agent(s), HDV, or HDV-like agents in three patients. Reactivation of chronic hepatitis B was an important cause of apparent acute hepatitis in heterosexual male HBsAg carriers from an area with a high prevalence of HBV infection.