Direct cloning and expression of PCR amplified DNA and RNA sequences: application to the hepadnaviruses nucleocapsid proteins

Gene amplification may benefit from the construction of primers that augments the speed at which cloning and protein expression proceeds. Such primers include EcoRI or HindIII linkers as well as an in phase initiation or termination codon. PCR was carried out directly from viral particles of human hepatitis B virus (HBV) and woodchuck hepatitis virus (WHV) without DNA purification and from RNA extracted from WHV infected liver. Amplified products were directly cloned in the pKK223-3 expression vector under the control of the tac promoter. The characterization of the recombinant clones expressing the nucleocapsid protein (C protein) was done by direct incubation of the filter with 125I-labelled anti-HBc and confirmed by radioimmunoassay and Western-blot analysis. This procedure allows easy selection of recombinant clones expressing a given protein and could be applied to many other genes.

Diagnostic markers of viral hepatitis B and C

Hepatitis B virus (HBV) serology has become extremely refined. As well as the recognised hepatitis B surface (HBs), hepatitis B core (HBc), and hepatitis B e (HBe) antigen-antibody systems, new markers have been introduced including pre-S1, pre-S2 for the envelope and the functional X protein. New automates have been introduced allowing flexibility in the different tests according to precise needs. The monitoring of pre-S1 antigen provides a relevant correlate of viral replication. The quantitative determination of HBV-DNA, pre-S1 Ag, and IgM anti-HBc seem most useful for the decision to use, and the monitoring of, antiviral treatment. Second generation ELISAs detect antibodies to three sets of hepatitis C virus (HCV) protein including the c22 core, and c33, and c100, which correspond to the non-structural regions (NS3 and NS4, respectively). Second generation ELISAs require confirmation by supplement assays, but their biggest limitation is the delayed appearance of anti-HCV after primary infection. In addition 10% of chronic infections with liver disease still remain seronegative despite circulating HCV RNA in serum or liver, or both. Much progress still has to be made before HCV serology can reach the level of sophistication of HBV.

New assays for quantitative determination of viral markers in management of chronic hepatitis B virus infection

We performed a quantitative study of serum hepatitis B virus (HBV) markers, including new parameters such as pre-S1 antigen (Ag), pre-S2 Ag, and anti-HBx, in 88 chronic hepatitis B surface antigen (HBsAg) carriers. New IMx assays for HBsAg and immunoglobulin M (IgM) anti-HBc detection were also used. The population studied was composed of 65 chronic hepatitis cases (40 positive for hepatitis B antigen [HBeAg] and 25 positive for anti-HBe) and 23 anti-HBe-positive, asymptomatic HBsAg carriers. Serum HBsAg levels detected by IMx were higher in HBeAg-positive than in anti-HBe-positive HBsAg carriers (all patient subgroups included) and correlated with the serum HBV DNA level (P = 0.0001). Both pre-S1 and pre-S2 Ags were detected by enzyme immunoassays in almost all HBsAg carriers. Both pre-S1 and pre-S2 Ag titers correlated positively with the serum HBsAg concentration (P = 0.0001), but only the pre-S1 Ag titer correlated with the level of serum HBV DNA (P = 0.02). The detection of low levels of IgM anti-hepatitis B core (anti-HBc) antibodies by IMx was associated with the presence of liver disease (P = 0.05) but not with the level of viral replication. The prevalence of anti-HBx antibodies detected by the enzyme immunoassay was slightly, although not significantly, higher in patients with high levels of HBV DNA (greater than 100 pg/ml) than in patients without detectable HBV DNA (P = 0.16). In anti-HBe-positive chronic HBsAg carriers, the quantitative detection of serum HBV DNA, pre-S Ag titers, and IgM anti HBc allowed us to predict which patients suffered from chronic liver disease and/or supported viral replication (P < 0.05). In a follow-up study of eight patients undergoing antiviral therapy, the clearance of both pre-S1 Ag and HBV DNA was associated with a subsequent clearance of HBV. Therefore, the quantitative determination of HBV DNA, pre-S Ags, IgM anti-HBc may prove useful for the decision to use and the monitoring of antiviral therapy, especially in anti-HBe-positive HBsAg carriers.

Transmission of serologically silent hepatitis B virus along with hepatitis C virus in two cases of posttransfusion hepatitis

The polymerase chain reaction (PCR) was used to investigate the presence of hepatitis B virus (HBV)-related DNA sequences in blood from three blood donors and two transfusion recipients who developed posttransfusion non-A, non-B hepatitis (NANBH). In the first case, the sole donor was positive for antibody to hepatitis B surface (HBs) and core (HBc) antigens and had elevated alanine aminotransferase (ALT) levels, while the recipient had no HBV serologic markers. Both the donor and the recipient had serologic markers of hepatitis C virus (HCV) and were found positive for HBV DNA and HCV RNA sequences by PCR. The second case involved two donors and one recipient. Serologic tests for conventional HBV markers were negative in all three individuals, but one of the donors had elevated ALT. HBV DNA sequences were detected by PCR in the serum of the recipient and of the donor with high ALT, but not in the serum of the donor with normal ALT. Anti-HCV was detected in the serum of the recipient and of the suspect donor but not in that of the donor with normal ALT. The sequences amplified in the S region and determined after cloning of PCR products for both donor-recipient pairs were indistinguishable from each other and identical to the sequence of the major HBV subtype of adw in the first case and ayw in the second case. Furthermore, for the second case, an identical single-point mutation was found in both the donor and the recipient. These data confirm the transmission of conserved HBV sequences together with HCV in posttransfusion NANBH.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of pre-C region mutation in woodchuck hepatitis virus from seroconverted woodchucks

Woodchuck hepatitis virus, which shares a large degree of homology with human HBV, was examined for indications of mutational variants. No alteration in the pre-C region was found, but as in HBV, viral DNA could still be detected by PCR after seroconversion to anti-WHe.

Functional epitope analysis of the human CD11a/CD18 molecule (LFA-1, lymphocyte function-associated antigen 1) involved in HIV-1-induced syncytium formation

After binding to the CD4 receptor, the human immunodeficiency virus 1 (HIV-1) may enter the T cell and induce the formation of multinucleated giant cells (syncytia). As well as the CD4 molecule, other molecules, such as the lymphocyte function-associated antigen 1 (LFA-1, CD11a/CD18) have been shown to be involved in HIV-1-mediated cell fusion. This study was designed to define regions on the human CD11a/CD18 molecule important for the HIV-1-induced syncytium formation. A CD11a/CD18 MoAb panel discriminating at least five distinct and spatially distant domains on the LFA-1 molecule was used. Comparison of the functional activity of different MoAbs demonstrated that all epitopes of the LFA-1 molecule were not of equal importance in HIV-1-induced syncytium formation between H9.III cells chronically infected with HIV-1 and uninfected CD4+ SupT1 cells. We also demonstrated that CD11a/CD18 MoAbs inhibit syncytia formation only at the level of the uninfected SupT1 cells, suggesting that the LFA-1 molecule expressed on SupT1 cells interacts with ligand(s) expressed on the infected H9.III cells. Two potential LFA-1 receptors on the H9.III cells were tested: the ICAM-1 molecule (intercellular adhesion molecule 1, CD54) and the HIV-1 transmembrane glycoprotein 41 (gp41). A CD54 MoAb (84H10) partially inhibited syncytia formation, thus demonstrating the involvement of the ICAM-1 molecule in the HIV-1-mediated cell fusion. However, the CD11a/CD18 MoAbs do not inhibit binding of the viral envelope glycoprotein gp41 to the cell surface, irrespective of the MoAb concentration used. Although we have not been successful in identifying all candidate fusion receptors for the LFA-1 molecule, these data suggest that some LFA-1 regions are important for syncytium formation and, therefore, in the cell-to-cell transmission of virus and in the spread of infection.

Detection of pre-S1 proteins in peripheral blood mononuclear cells from patients with HBV infection

The presence of pre-S1 proteins in peripheral blood mononuclear cell (PBMC) samples from 115 patients with different forms of hepatitis B virus (HBV) infection was investigated by Western blot. Among 67 chronic HBsAg carriers, HBV antigens were detected in the PBMC in 80% for HBsAg, 27% for HBc/e Ag and 34% for pre-S1 proteins. The detection of pre-S1 proteins in PBMC was significantly associated with the presence of serum markers of HBV replication (HBV DNA and/or DNA polymerase). In the group of 48 consecutive patients negative for serum HBsAg, but positive for anti-HBc with or without anti-HBs, HBsAg and pre-S1 proteins could be detected in PBMC. This finding was more frequent among anti-HIV-positive patients (77 and 23% of the cases, respectively) than in the negative ones (23 and 4% of the cases, respectively). The detection of HBV DNA and polyadenylated RNA in some of the PBMC samples positive for HBV proteins suggests that these proteins may be expressed in PBMC, especially during intense HBV replication. In patients negative for serum HBsAg, PBMC may constitute a reservoir of HBV.

Correlation between HBV DNA detection by polymerase chain reaction and Pre-S1 antigenemia in symptomatic and asymptomatic hepatitis B virus infections

The presence of hepatitis B virus (HBV) genome in sera from 73 symptomatic and asymptomatic HBsAg carriers was studied by the polymerase chain reaction (PCR) with primers specific for the S and C regions. Pre-S proteins of the HBV envelope were detected in serum by a specific monoclonal antibody in a double immunoradiometric assay. Out of twenty-five symptomatic patients with chronic active hepatitis (14 with HBeAg and 11 with anti-HBe), all were positive for HBV DNA by PCR, while 14/14 HBeAg and 2/11 (18%) of the anti-HBe patients were positive by dot blot hybridization. All but one anti-HBe patient (96%) carried Pre-S1 proteins. Among the asymptomatic HBsAg carriers, HBV DNA was detected by PCR in 14/14 (100%) HBeAg positive patients and in 25/34 (73%) anti-HBe positive patients. Pre-S1 proteins were found, respectively, in 14/14 (100%) and 11/22 (50%) of the same cases tested in parallel. The 20 healthy blood donors devoid of HBV markers and with normal transaminases tested were found negative for HBV DNA using PCR. Out of 12 patients who recovered from acute hepatitis B, all were found negative by PCR analysis after a mean follow up of 1 year after seroconversion to anti-HBs. When serial samples from 2 patients (one with acute hepatitis B, the other with chronic hepatitis B) were tested for the presence of HBV DNA and of Pre-S1 proteins, both markers showed parallel development.(ABSTRACT TRUNCATED AT 250 WORDS)

Early and frequent detection of HBxAg and/or anti-HBx in hepatitis B virus infection

To clarify the significance of the X gene of hepatitis B virus, we have tested for anti-HBx in the serum and HBxAg in the liver at different stages of the natural history of hepatitis B virus infection. Sera were screened by enzyme-linked immunosorbent assay and positive results confirmed by immunoblot. Purified recombinant MS2 Pol-HBx fusion protein was used as target for both assays. Among serial sera of patients with nonfulminant acute hepatitis, 24 of 64 patients (37.5%) were positive for anti-HBx. In fulminant cases, 15 of 36 patients (42%) had anti-HBx. In chronic hepatitis patients with high rates of hepatitis B virus replication, we found a significantly (p less than 0.01) higher prevalence of anti-HBx, 14 of 25 patients (56%), than in those with low replication, 14 of 66 patients (21%), or among asymptomatic HBsAg carrier blood donors (20 of 126 = 16%) without detectable hepatitis B virus replication (p less than 0.0001). The highest prevalence of anti-HBx was found in HBsAg carriers with cirrhosis (41 of 54 patients = 76%) and/or with hepatocellular carcinoma (18 of 33 patients = 54%). The findings suggest that anti-HBx appears as a common and early marker of hepatitis B virus infection, transient in self-limited hepatitis but persisting with progression to chronicity. In chronic hepatitis, the prevalence of anti-HBx correlated with the intensity and duration of hepatitis B virus replication but neither with the severity of the liver disease nor with malignant transformation per se.(ABSTRACT TRUNCATED AT 250 WORDS)

Different forms of hepatitis B virus DNA and expression of HBV antigens in peripheral blood mononuclear cells in chronic hepatitis B

The presence of both hepatitis B virus (HBV) DNA and HBV antigens (HBsAg, HBeAg) was assessed in peripheral blood mononuclear cells (PBMC) from 32 patients chronically infected with HBV. Three different molecular forms of HBV DNA were observed: free monomers (5), high-molecular-weight free concatemers (11), and integrated HBV DNA (9). The HBV DNA patterns in the PBMC were different from those found in liver and did not correlate with any specific profile of serum HBV markers. When the same PBMC were assayed for HBsAg, 22 of the 25 HBV DNA positive samples, but only three of the seven HBV DNA negative samples, were positive. By contrast, none of the PBMC samples from five healthy HBV vaccine recipients gave any positive signal in the HBV DNA or HBsAg assays. In some patients, T and B cells, monocytes, and polymorphonuclear (PMN) cells were assayed separately, showing that the DNA pattern was similar for these different leucocytes subsets and ruling out the possibility that these patterns might reflect PMN cell contamination. Thus, in chronic HBV infection, 87.5% (28/32) of patients were found to contain at least one HBV marker in their PBMC, and a strong correlation was found between the presence of HBV DNA and viral antigens, suggesting a specific expression of HBV encoded proteins.

Delta infection in chronic HBs Ag carriers in Tunisia: high prevalence in chronic asymptomatic HBs Ag carriers and in HBs Ag positive cirrhosis

The presence of hepatitis B virus DNA, delta antigen and anti-delta antibodies was examined in 159 Tunisian chronic HBs Ag carriers: 45 were asymptomatic and 114 suffered from cirrhosis. Serum hepatitis B virus DNA was detected in two (4.5%) asymptomatic HBs Ag carriers and in 11 (10%) HBs Ag positive cirrhosis patients. The prevalence of HDV infection determined by the presence of anti-delta was relatively high in asymptomatic HBs Ag carriers (33%) and in HBs Ag positive cirrhosis patients (21%). Active ongoing HDV infection, detected by serum HD Ag and anti-delta IgM, was shown in five patients with cirrhosis and active hepatitis B virus replication. We conclude that hepatitis delta virus may be endemic in Tunisia and does not always inhibit hepatitis B virus replication.

[Significance of the expression of pre-S proteins in mononuclear blood cells in chronic hepatitis caused by the hepatitis B virus]

In chronic viral type B hepatitis, the presence in the serum of pre-S proteins of hepatitis B virus (HBV) envelope reflects viral replication. As peripheral blood mononuclear cells (PBMC) are known to be target cells for HBV replication, the aim of our study was to investigate the clinical relevance of pre-S protein expression in PBMC. Fifty-seven patients with chronic type B hepatitis and HBs antigenemia were studied. Following separation using the Ficoll gradient, the PBMC were lysed and studied for pre-S proteins by Western blot. HBs Ag and HBc/e Ag were assayed in parallel by radioimmunoassay. HBs Ag was detected in PBMC in 86 percent of cases, HBc/e Ag in 28 percent of cases and pre-S proteins in 34 percent of cases. A statistically significant association was found between the presence of HBc/e Ag in PBMC and both the serum HBe Ag (chi 2 test, p less than 0.01) and the serum viral DNA/DNA polymerase (t test, p = 2.10(-4)). The pre-S protein expression in PBMC was significantly associated with higher levels of DNA/DNA polymerase activity (chi 2 test, p less than 0.05). The expression of pre-S proteins in PBMC appears therefore to correlate with the HBV viral replication phase. The HBc/e Ag and pre-S protein detection in PBMC therefore offers a reliable non invasive approach to tissular viral replication. The clinical relevance of pre-S testing in PBMC was illustrated by the study of 12 cases of chronic active hepatitis positive for anti-HBe but with no or low level of serum DNA polymerase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

[Prevalence of viral hepatitis B markers in the region of Tataouine (southern Tunisia)]

Tataouine (South Tunisia) has been subject to several viral hepatitis epidemics during these last years. Prospective study has been conducted to define the prevalence of HVB infection. It has examined 511 cases, the age of whom was between 1 month and 70 years, reported in groups through the OMS recommendations, taking into account the number of inhabitants in each area. The global prevalence was 6.2% for HBs Ag and 18.5% for HBs antibody. These results were not different from the frequencies observed within the Tunisian population in general. The analysis of this study according to these groups, shows that in three areas (Ras El Oued, Bir 30, Dhibet) 60 to 80% of cases have at least one of HVB marquers, whereas the prevalence in other areas (Rogba) was very weak. The geographic repartition of HVB infection corresponds approximatively to areas that have been the most infected by the last hepatitis epidemics. A second study has completed and confirmed the results of the first one, taking into consideration a more important number of cases from areas of strong and weak endemicity. 596 sera have been examined in Rogba which counts 2000 inhabitants and is a weak endemicity area. 528 sera have been examined in the three areas of strong endemicity: 199 in Bir 30, 201 in Dhibet and 128 in Ras El Oued, which count around 2000 inhabitants, too. The percentage of cases presenting at least one of HVB serological marquers reaches 84 in Dhibet, 70 in Ras El Oued, 50 in Bir 30 and 24 in Rogba. This HBs Ag frequency is 3.8% in Rogba, 15% in Bir 30, 24% in Ras El Oued and 26.3% in Dhibet. It seems that the HVB is the virus of hepatitis epidemics observed in Tataouine at least in the three strong endemicity areas.

Anti-HBc screening for the prevention of perinatal transmission of hepatitis B virus in France

As anti-HBc screening has been proposed for blood donor testing, we investigated its effectiveness during pregnancy. Among 4,023 successive pregnant women screened for anti-HBc, 539 (13.4%) were positive and further tested for HBsAg and anti-HBs. HBsAg was found in 73 (1.81%) and anti-HBc only was positive in 66 (1.64%). Among the 73 women positive for HBsAg, HBV DNA was found in the serum of seven, the cord blood of two, the placenta of three. Of the 58 infants given HBV immunoglobulins and vaccine, only four had transient HBsAg. None of the 66 women positive for anti-HBc only had anti-HBc IgM, HBeAg, or HBV DNA in serum, cord blood or placenta but five women became HBsAg positive before, at, or after delivery. Among the infants born of these 66 mothers, three had high ALT, two had HBsAg and one HBV DNA without HBsAg. Screening for anti-HBc may be cost effective, at least in low HBV prevalence areas, since there is evidence for infectivity of pregnant women positive for anti-HBc only.

High affinity human monoclonal antibodies directed against hepatitis B surface antigen

Peripheral blood mononuclear cells from donors immunized with hepatitis B vaccine (Pasteur Hevac B) were transformed with Epstein-Barr virus. Two polyclonal cell lines, producing antibodies to hepatitis B surface antigen were established and cloned. Seven clones were isolated; they secreted between 10 and 20 micrograms/ml of HBs specific IgG1 kappa or lambda antibody with anti-HBs titer of 300-800 IU/ml. These human antibodies expressed the anti 'a' specificities and had high affinity and avidity; their potential use as reagents for hepatitis B virus detection and for passive immunotherapy is under study.

Prevalence and significance of hepatitis B virus antigens: expression in peripheral blood mononuclear cells in chronic active hepatitis

One-hundred four chronic active hepatitis (CAH) patients were investigated for the expression of the hepatitis B virus (HBV) surface and core gene products (HBs Ag, HBc/HBe Ags) in peripheral blood mononuclear cells (PBMC). Two-thirds of 59 HBs antigenemic patients expressed HBs Ag in PBMC but 26% of cases positive for both anti-HBs and anti-HBc also expressed HBs Ag while none of the controls reacted. Among HBs antigenemic patients, only those who replicated HBV express the core gene products (HBc and/or HBe Ag) in PBMC, and high replicators did so more often than low replicators (P less than 0.05). The HBs Ag prevalence in PBMC, although slightly higher among HBe Ag/DNAp-positive cases could not be correlated with the intensity of HBV replication. In 16 cases (8 replicants and 8 nonreplicants) HBV DNA was detected by DNA hybridization spot test, while 8 controls devoid of HBV markers were negative. Both T and non-T cells reacted similarly for antigenic or genomic HBV markers. When the expression of HBV gene products in PBMC among 43 cases with HBs antigenemia was compared with that in the liver, a good correlation was found in 70% of cases for HBs Ag but in only 40% for HBc and HBe Ags. By contrast, among 38 cases lacking HBs Ag in the serum but positive for anti-HBc with or without anti-HBs, concordance between liver and PBMC expression of core gene products (69%) was better than for HBs antigenemic patients (40%). These data suggest that PBMC including T lymphocytes may represent the second-best HBV target and may mimic the steps of HBV cycle within hepatocytes.

Evidence for the presence of duck hepatitis B virus in wild migrating ducks

A virus closely related to duck hepatitis B virus (DHBV) was isolated from serum and liver samples of wild migratory ducks (mallards) caught in two separate wildlife reserve parks in France. In the first one (Dombes region) 12% of wild mallards were positive for DHBV, and in the second (River Somme) 3% of mallards were found positive. The DHBV isolated from the serum of wild mallards was also associated with an endogenous DNA polymerase activity capable in vitro of completing a partially double-stranded viral DNA into a fully double-stranded DNA of 3 kb. The various replicative DNA forms reported for DHBV were also detected in the liver of wild viraemic mallards. The DNA restriction enzyme pattern of the wild mallard strain differed from that of American and French strains of DHBV. The wild mallard strain DHBV was experimentally transmitted to mallard and Pekin ducklings and induced a chronic viraemia in both varieties of infected birds. This strain might be the common ancestor of all DHBV strains isolated from domestic ducks world-wide. The discovery of a DHBV-related virus in the natural wild population might be an important clue in the study of the different roles of environmental, host and viral factors in the pathogenesis of DHBV infection, and their possible oncogenic action in ducks.

Woodchuck hepatitis virus infection: serologic and histopathologic course and outcome

Five out of seven American woodchucks inoculated with woodchuck hepatitis virus developed antigenemia after 2 to 13 weeks followed by an antibody response. One animal became a carrier, and another animal exhibited a primary antibody response. Clinical disease was not obvious and aminotransferase elevation could not be demonstrated. Liver biopsy showed mononuclear portal infiltration and little parenchymal cell necrosis.

Immunopathologic aspects of woodchuck hepatitis

The natural history of infection with woodchuck hepatitis virus (WHV) has been studied in a colony of 38 Marmota monax. Besides serologic assessment for WHV markers, light-microscopic findings of 61 liver biopsies were correlated with the results of immunofluorescence analysis for nucleocapsid (WHcAg) and surface (WHsAg) antigens. Twenty-four chronic WHsAg carriers all featured signs of continuous viral replication. Two major immunomorphologic patterns were observed in their livers: 1) portal hepatitis in which WHcAg accumulated in the cytoplasm and WHsAg was associated with the hepatocyte membrane and 2) periportal hepatitis in which WHcAg shifted toward nuclear localization and WHsAg became mostly intracytoplasmic. Progression from portal to periportal hepatitis, observed in 7 woodchucks, appeared to be induced by a partial recovery of specific immune reactivity to WHV, insufficient, however, to interrupt WHV replication. Deposits of WHsAg and immunoglobulins were present in the kidney and spleen of animals with severe hepatitis.

Comparison of properties of woodchuck hepatitis virus and human hepatitis B virus endogenous DNA polymerases

The principal properties of the DNA polymerases of woodchuck hepatitis virus and human hepatitis B virus were compared. The enzymes of both viruses exhibited optimal activities in the same range of pH, ionic strength, and MgCl2 concentration. Like human hepatitis B virus DNA polymerase, the woodchuck hepatitis virus DNA polymerase was strongly inhibited by phosphonoformic acid but not by phosphonoacetic acid and aphidicolin. Similar inhibition patterns for both enzymes were observed with arabinofuranosyl nucleotides (9-beta-D-arabinofuranosyladenine-5'-triphosphate, 1-beta-D-arabinofuranosylcytosine-5'-triphosphate, 1-beta-D-arabinofuranosylthymine-5'-triphosphate) and dideoxythymidine triphosphate, whereas no effect was obtained with corresponding nucleosides. The therapeutic significance of these results and the relevance of the woodchuck as an experimental animal model for the study of human hepatitis B virus infections are discussed.

[Spontaneous and experimental infection of alpine marmots (Marmota marmota) by the North American woodchuck hepatitis virus (Marmota monax). Initial results]

Summer's discovery in 1978 of a DNA virus, very close to human Hepatitis B virus in a woodchuck population in the U.S.A. (Pennsylvania) was a confirmation of the first description made by Snyder at Penrose Research Laboratory (Philadelphia). It was the first animal model of human B hepatitis infection. The comparative study of morphological, ecological and ethological characteristics of the marmot (Marmota marmota) and the woodchuck (Marmota monax) enables an easy distinction between these two species. The natural infection of M. monax by the WHV shows that the woodchuck is a good model for human B hepatitis and should be extended to M. marmota. A sample of 24 marmots caught in the Alpes of Haute-Provence has not revealed any spontaneous infection in these animals by the woodchuck virus. The failure of experimental inoculation of the marmot (24 animals) with the WHV confirms the refractory status of this species (no viremia and very low and short serological response with or without an immunosuppressive treatment). These preliminary results require a confirmation in other animals of different age and geographical region and also by using more specific tests such as molecular hybridization, research on DNA polymerase and direct transfection trials.

Use of the cross-reactivity with hepatitis B virus antigens and antibodies for the demonstration of a woodchuck hepatitis virus 'e' antigen-antibody system

Woodchucks hepatitis virus (WHV)-associated antigens and antibodies were studied using current sensitive radio- or enzyme immunoassays (RIA, EIA). A significant cross-reactivity was observed between hepatitis B surface antigen (HBsAg) and woodchuck hepatitis surface antigen (WHsAg) using RIA or EIA (Abbott Laboratories, North Chicago, Ill., U.S.A.) although not with two other commercial EIA tested (Organon Technika, Oss, The Netherlands; Behringwerke AG, Marburg, F.R.G.). A weak but significant reactivity was also found when woodchuck sera positive for WHsAg or anti-WHs by immunodiffusion were tested for HBeAg and anti-HBe by RIA, suggesting the existence of a WHeAg-anti-WHe system in infected woodchucks. The specificity of this e-anti-e reactivity in the woodchuck was further confirmed by successful absorption experiments. WHsAg and WHeAg could be distinguished serologically by immunodiffusion and separated from each other by ultracentrifugation and ammonium sulphate precipitation. A WHeAg preparation was used to boost the presumed natural antibody activity of an immune woodchuck. The specific anti-HBe response detected by RIA during the immunization experiments demonstrated the existence of a soluble WHeAg cross-reacting with the human HBe-anti-HBe system. This was confirmed in immunodiffusion by a partial identity between the precipitin lines formed by the WHeAg-anti-Whe and HBeAg-anti-HBe reaction. Whether the WHe-Ag-anti-WHe system wil mimick HBeAg and anti-HBe in all their clinico-pathological correlations, deserves further study.

Identification and detection of long incubation non-A, non-B hepatitis virus and associated antigens or antibodies

Three distinct antigen/antibody systems supposedly associated with an HBV-like virus of non-A, non-B hepatitis have been identified. Because of previously demonstrated cross-reactivity with HBe/3 and HBc antigens and other analogies the following terminology is tentatively used. 1. The previously reported serum antigen has been redesignated non-A, non-B e antigen, since it is equivalent to HBe/3 Ag and cross-reacts with it. Non-A, non-BeAg or Ab were detected in 51/62 post-transfusion and 11/56 sporadic acute non-A, non-B hepatitis cases, and in 12/14 cases affecting staff members. In non-A, non-B chronic persistent or active hepatitis and cryptogenic cirrhosis, the prevalence was similarly high: 14/18, 22/48 and 12/18 respectively. Ten out of 26 implicated blood donors were found positive for non-A, non-BeAg accounting for 7 out of 8 post-transfusion cases. A high prevalence of non-A, non-BeAg was also found in haemophiliacs (11/48) and haemodialysed patients (6/42), whereas anti-non-A, non-Be was respectively detected in 4/48 and 6/42 of these cases. 2. Using immunofluorescence, a second antigen termed non-A, non-BcAg has been identified in liver biopsies from 55/84 non-A, non-B chronic hepatitis or cryptogenic cirrhosis cases. All 8 positive biopsies examined by electron microscopy revealed clusters of 22--25 nm intranuclear particles identical to those described in chimpanzees. Anti-non-A, non-Bc detectable by counter-electrophoresis and indirect immunofluorescence was found in the serum of all patients of which biopsy was positive for non-A, non-BcAg. Anti-non-A, non-Bc was also detected in 5/5 non-A, non-BeAg positive cases of post-transfusion hepatitis, 2--6 weeks after onset end remained positive for the 6 month follow-up period. 3. A third antigen, tentatively designated non-A, non-BsAg, has been found less frequently than non-A, non-BeAg in serum. However, it was detectable in 3/18 and 2/12 washed ultracentrifugation pellets of sera positive for non-A, non-BeAg or anti-non-A, non-Be, respectively.

[Identification of a virus similar to hepatitis B virus in non-A non-B hepatitis]

Hepatitis B virus-like particles (including DANE particles) with DNA polymerase activity but negative for HBs Ag have been identified in NON-A, NON-B hepatitis sera positive for HC Ag. Although specifically associated with the particles, HC Ag is not a surface antigen of the hepatitis C virus identified here for the first time. The relationship of this agent with HBV seems obvious, and deserves further study.