Large hepatitis B surface antigen polypeptides of Dane particles with the receptor for polymerized human serum albumin

HD-03/ES: A Herbal Medicine Inhibits Hepatitis B Surface Antigen Secretion in Transfected Human Hepatocarcinoma PLC/PRF/5 Cells

HD-03/ES is a herbal formulation used for the treatment of hepatitis B. However, the molecular mechanism involved in the antihepatitis B (HBV) activity of this drug has not been studied using in vitro models. The effect of HD-03/ES on hepatitis B surface antigen (HBsAg) secretion and its gene expression was studied in transfected human hepatocarcinoma PLC/PRF/5 cells. The anti-HBV activity was tested based on the inhibition of HBsAg secretion into the culture media, as detected by HBsAg-specific antibody-mediated enzyme assay (ELISA) at concentrations ranging from 125 to 1000 μg/mL. The effect of HD-03/ES on HBsAg gene expression was analyzed using semiquantitative multiplex RT-PCR by employing specific primers. The results showed that HD-03/ES suppressed HBsAg production with an IC₅₀ of 380 μg/mL in PLC/PRF/5 cells for a period of 24 h. HD-03/ES downregulated HBsAg gene expression in PLC/PRF/5 cells. In conclusion, HD-03/ES exhibits strong anti-HBV properties by inhibiting the secretion of hepatitis B surface antigen in PLC/PRF/5 cells, and this action is targeted at the transcription level. Thus, HD-03/ES could be beneficial in the treatment of acute and chronic hepatitis B infections.

Efficient inhibition of hepatitis B virus replication by hepatitis delta virus ribozymes delivered by targeting retrovirus

Background

Hepatitis delta virus (HDV) ribozyme is an attractive molecular tool that can specifically recognize and catalyze the self-cleavage of the viral RNA phosphodiester backbone. However, a major obstacle in the medical application of the HDV ribozyme is the lack of specificity in the delivery of the ribozyme to defined target cells.

Results

The objective of this study was to determine whether retroviral vectors can deliver the HDV ribozyme into the target cells and to elucidate whether HDV ribozyme plays a role in hepatitis B virus (HBV) replication. In our study, the transduction of helper-free pseudotyped retrovirus, which showed a broad host range, in human hepatoma cells was performed under 2 conditions, that is, in the presence of polymerized human serum albumin (pHSA) and in the absence of pHSA. The transduction ability in the presence of pHSA was higher than in the absence of pHSA. Moreover, HBsAg and HBeAg levels after transductions with pHSA were significantly lower than those in the absence of pHSA, thus indicating that the recombinant retrovirus had HBV-specific cleavage activity and targeted HepG2215 cells.

Conclusions

These data suggest that this system provides a new approach for targeting hepatocytes and has a great potential in gene therapy for HBV infection.

Hepatitis B vaccine containing surface antigen and selected preS1 and preS2 sequences. 1. Safety and immunogenicity in young, healthy adults

The safety and immunogenicity of a yeast-derived recombinant hepatitis B virus (HBV) vaccine containing surface antigen (S) and selected preS1 and preS2 sequences (S-L*) were compared with those of a vaccine prepared with S alone (Engerix-B). S-L* consisted of composite particles containing S and L* at a ratio of 70/30. L* encompassed amino acid residues 12-52 of preS1 residues 133-145 of preS2, and the entire S domain. A total of 100 healthy, HBV-seronegative, young adults were randomized to receive 20 micrograms/dose of either S-L* or Engerix-B under double-blind conditions according to a 0-, 1-, 2-, 12-month schedule. In vivo humoral and in vitro lymphoproliferative responses to S and preS regions were monitored. Addition of the selected preS sequences to S did not enhance the in vivo humoral anti-HBs response but improved the in vitro stimulating capacity of the antigen (L*) in S-L* primed subjects.

Improved immunogenicity in mice of a mammalian cell-derived recombinant hepatitis B vaccine containing pre-S1 and pre-S2 antigens as compared with conventional yeast-derived vaccines

The widely used hepatitis B virus (HBV) vaccines consist of the small hepatitis B surface (SHBs) protein produced in transfected yeast cells. The frequency of non-responders, especially among immunocompromised patients, has increased the demand for a more immunogenic vaccine. We evaluated the immunogenicity of recombinant HBs 20 nm particles secreted by transfected Chinese hamster ovary (CHO) cells, Bio-Hep-B (BioTechnology General Ltd, Israel), and compared it with yeast-derived vaccines. The CHO-derived vaccine contains the small hepatitis B surface antigen (SHBs protein) as the major component, as well as the middle HBs (MHBs, pre-S2) and the large HBs (LHBs, pre-S1) antigens. Nine groups of ten female Balb/c mice, 4-6 weeks old, were injected once intraperitoneally (i.p.) with 0.09, 0.27 or 0.81 micrograms of each of three vaccines: Bio-Hep-B or two conventional yeast-derived recombinant vaccines, Engerix-B (SmithKline Beecham, Belgium) and H-B-Vax II (Merck, Sharp & Dohme, USA) containing only non-glycosylated SHBs antigen. After 30 days, 40% of the mice injected with 0.09 microgram Bio-Hep-B had seroconverted, but none of the mice receiving the same dose of the other vaccines. The immunogenic dose in 50% of the mice at day 14 after injection was 0.13 microgram for Bio-Hep-B, but over 0.81 microgram for the other two vaccines. Mice of the strain B10/M (which are unresponsive to SHBs and MHBs antigens at the T-cell level) developed 100-fold higher anti-HBs titres after immunization with 1 microgram of Bio-Hep-B i.p., as compared with mice receiving the same amount of yeast-derived HBsAg vaccines.(ABSTRACT TRUNCATED AT 250 WORDS)

PreS1 deleted variants of hepatitis B virus in patients with chronic hepatitis

Defective hepatitis B virus lacking 183 bases of the 3'-terminus part of the preS1 region was found in the sera of two patients with chronic hepatitis B virus infection. Results of sequencing analysis of samples with or without polymerase chain reaction yielded the same result, proving that this deletion was not due to an artifact obtained during polymerase chain reaction. One of the deletion ends lay in TCAGG that appeared five times in the genome of subtype adr and the other end was identified as TCAGG in direct repeats of the genome. The mutated hepatitis B virus became predominant in one patient's serum only after consecutive interferon therapy, suggesting that the deleted part might play a role in viral elimination from the circulation.

Significance of measurement of pre-S2 antigen for the prevention of vertical transmission of hepatitis B virus in infants born to HBsAg carrier mothers

The significance of pre-S2 antigen (pre-S2 Ag) as a marker of hepatitis B virus (HBV) infection, especially in infants born to HBsAg carrier mothers who are HBeAg-negative or HBeAg-positive, was evaluated. Pre-S2 Ag was measured by enzyme immunoassay. HBsAg carrier mothers who were HBeAg-negative and HBeAb-positive were divided into two groups: group A, mothers whose infants were not infected with HBV (n = 10) and group B, mothers whose infants were infected with HBV (n = 13). Absorption rates of pre-S2 Ag in group A and B were 0.09 +/- 0.04 and 1.36 +/- 0.95, respectively. The values for pre-S2 Ag in group B were significantly higher than those in group A. Values for pre-S2 Ag among HBsAg carrier mothers who were HBeAg-positive and HBeAb-negative were also measured by reverse passive hemagglutination. In the same way, HBsAg carrier mothers who were HBeAg-positive and HBeAb-negative were divided into two groups: group C, mothers whose infants did not become HBsAg carriers (n = 15) and group D, mothers whose infants became HBsAg carriers (n = 11). The titers of pre-S2 Ag (reverse passive hemagglutination) in group C and D were 2(5.75) +/- 1.68 and 2(10.45 +/- 1.69), respectively. The values for pre-S2 Ag in group D were significantly higher than those in group C. The values for pre-S2 Ag as markers of infectivity became higher with increasing amounts of HBV-DNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical significance of low or negative titer of antibody to hepatitis B core antigen during the course of chronic hepatitis B virus infection in adolescents

Antibody to hepatitis B core antigen (anti-HBc) was measured by radioimmunoassay in 127 asymptomatic hepatitis B surface antigen (HBsAg) carriers (ASC; mean age 19) who had normal serum alanine aminotransferase (ALT) levels and 16 patients with chronic hepatitis B (CH; 19). All 16 CH patients, who were positive for hepatitis B e antigen (HBeAg) and 5 ASC cases who were negative for both HBeAg and its antibody (anti-HBe), had high anti-HBc titers. Anti-HBc titers in 27 (56.3%) of the 48 HBeAg-positive ASC and 18 (24.3%) of the 74 anti-HBe-positive ASC were relatively low. Two of the ASC were HBeAg-positive/anti-HBc-negative. In a follow-up study of the 19 HBeAg-positive ASC with low or negative anti-HBc titers, 5 had abnormal serum ALT levels and increased anti-HBc titers. In contrast, in the other 14 of these subjects, serum ALT levels remained normal and the low anti-HBc titers remained unchanged and/or decreased. The serological profile of HBsAg-positive/low or negative anti-HBc titer and increased anti-HBc titer with abnormal serum ALT levels are not necessarily exceptional in HBeAg-positive adolescent ASC. It is suggested that anti-HBc is associated with the liver damage that occurs before adolescence in chronic hepatitis B virus infection.

SDS-PAGE after micro-affinity adsorption for analysis of heterogeneous antigen polypeptides in individual sera

A method was developed for the analysis of heterogeneity in antigen polypeptides in individual sera. Polypeptides in sera were adsorbed by polystyrene beads coated with antibody in wells of a microplate. They were dissociated with a small volume of elutant, and transferred to slots on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Polypeptides separated on gel were then immunoblotted with antibodies labeled with horseradish peroxidase. The method was applied to analyze different populations of hepatitis B surface and e antigen polypeptides in sera from carriers of hepatitis B virus. Applicability to mass-scale and high sensitivity of the method would allow surveys of heterogeneous antigen polypeptides in serum for any biological significance.

The large surface protein of hepatitis B virus is retained in the yeast endoplasmic reticulum and provokes its unique enlargement

The coding sequences for each of the three envelope proteins of hepatitis B virus (HBV), the major (S), middle (M), and large (L) surface proteins, were expressed in Saccharomyces cerevisiae. Analysis by immunoelectron microscopy of thin sections of yeast cells showed that production of L protein but not of M or S protein provoked morphological changes in the yeast endoplasmic reticulum. A large accumulation of membranous structures connected with the perinuclear cysternae and specifically labeled by a monoclonal antibody directed against the amino-terminal (preS1) sequence of the L protein, was observed. The L protein was post-translationally modified by N- and O-linked glycosylation, indicative of its entry into the yeast secretory pathway and by N-myristoylation of its amino-terminal glycine residue. Deletion of this glycine residue resulted in the synthesis of a nonmyristoylated L protein. Proliferation of the endoplasmic reticulum was comparable in cells producing either the myristoylated or nonmyristoylated L protein, indicating that myristoylation alone is not responsible for the induction of the abnormal membrane morphology.

Changes of pre-S1 and pre-S2 antigens in sera of patients with hepatitis B virus infection

Polypeptides encoded by the pre-S1 and pre-S2 genes of hepatitis B virus (HBV) (pre-S1 antigen and pre-S2 antigen) were detected by enzyme-linked immunosorbent assay (ELISA) in 137 serum samples of patients with HBV infection. The HBV-DNA level closely correlated with the titer of pre-S antigens. However, HBV-DNA levels more closely correlated with the titer of the pre-S1 antigen [HBV-asymptomatic carrier (ASC): n = 40, r = 0.800, P less than 0.01; chronic hepatitis B (CH): n = 60, r = 0.730, P less than 0.01] than with the titer of the pre-S2 antigen [ASC: r = 0.675, P less than 0.01; CH: r = 0.575, P less than 0.01]. Thirty patients with CH, in whom hepatitis e antigen (HBeAg) was cleared after acute exacerbation (AE) [alanine aminotransferase (ALT) level greater than 200 IU/L] and the ALT level normalized, were followed for 12 months and classified into two groups: Group 1, those in whom HBeAg reappeared with an elevated ALT level within 12 months, and Group 2, those in whom HBeAg was persistently cleared from the serum and a normal ALT level continued. Of the 30 patients, 24 (80%) were classified into Group 1 and 6 (20%) were classified into Group 2. Changes in serum levels of HBV markers a month before and after AE were observed. The HBV-DNA level and DNA-P activity became negative after AE in both groups. The titer of pre-S1 antigen also decreased after AE, and no significant differences were observed between Group 1 and Group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Polymerized albumin binding to serum in various liver diseases: its significance and relation to hepatitis B virus infection

Sensitive and specific enzyme-linked immunosorbent assays (ELISA) were developed to detect separately the binding of polymerized human serum albumin (PHSA) to its antibody (A-PHSA) and to the hepatitis B surface antigen (HBsAg). A-PHSA was not detected in normal serum, whereas more than one-third to about half of sera from patients with acute liver cell injury showed this antibody. Frequency of A-PHSA positivity was low in chronic liver diseases, being relatively higher in those with continuing liver injury. A-PHSA detection was not related to seropositivity for HBsAg. PHSA binding of HBsAg positive sera showed a higher frequency of positivity in chronic carriers than acute hepatitis B. Of 172 asymptomatic HBsAg carriers, PHSA binding was demonstrated in 25 (15%), the frequency being significantly high if HBeAg was also present (84%). Binding was infrequent in sera having anti-HBe (2.9%) and in those negative for both HBeAg and anti-HBe (2.7%). Binding of HBsAg to PHSA was significantly higher than to human serum albumin (HSA). Immunoblotting of separated HBsAg components showed PHSA binding specifically to the high molecular weight peptide. PHSA binding in HBsAg positive serum may indicate the latter's infectivity as detected in a study of maternal-fetal transmission, where it demonstrates 100% infectivity in HBsAg and HBeAg positive mothers. PHSA possibly mediates the attachment of the HBV to the hepatocyte and a competitive binding between A-PHSA with HBsAg for PHSA may modulate the course of HBV infection.

Quantitative analysis of pre-S1 and pre-S2 in relation to HBsAg expression

Sera from four patients with acute hepatitis B and 87 patients with chronic hepatitis B were examined quantitatively for pre-S1 and pre-S2 antigens by solid-phase enzyme immunoassays. Pre-S1 and pre-S2 antigens were detected in HBsAg-positive sera irrespective of the presence of viral replicative markers, and their titers correlated with those of HBsAg (r = 0.74, p less than 0.01; r = 0.74, p less than 0.01, respectively). Sera positive for HBeAg showed higher titers of pre-S1 (p less than 0.01) and pre-S2 (p less than 0.01) antigens than sera negative for HBeAg. The titers of pre-S1 and pre-S2 antigens also correlated with the levels of HBV-associated DNA polymerase activity (r = 0.51, p less than 0.01; r = 0.59, p less than 0.01, respectively) and HBV-DNA (r = 0.50, p less than 0.01; r = 0.46, p less than 0.01, respectively). However, the ratios between the titers of pre-S antigens and HBsAg had no significant relationships with those viral replicative markers. These findings suggest that the expression of pre-S antigens is intimately related to the expression of HBsAg and that they are not useful as markers of viral replication. The ratios between the titers of pre-S antigens and HBsAg tended to be high in patients with chronic active hepatitis and high aminotransferase levels. This finding may have been due to the hepatic release of pre-S antigens, over-production of which may have some relationship to liver injury.

The preS1 antigen of hepatitis B virus is highly immunogenic at the T cell level in man

14 hepatitis B vaccine recipients who showed high titers of anti-hepatitis B surface antibodies in serum after booster immunization with a polyvalent hepatitis B surface antigen vaccine that contained trace amounts of hepatitis B virus (HBV) preS1 and preS2 envelope antigens were studied for their in vitro T cell response to these antigens. All 14 subjects displayed a significant proliferative T cell response to the S/p25 envelope region encoded polypeptide; 8 also responded to preS1, while only 1 showed a significant level of T cell proliferation to preS2. Limiting dilution analysis demonstrated that the frequency of preS-specific T cells in two of these vaccine recipients was higher than that of S/p25-specific T cells. T cell cloning was then performed and a total of 29 HBV envelope antigen-reactive CD4+ cloned lines were generated from two preS-responsive vaccines. 21 of these lines were S/p25 specific, 7 preS1 specific, and 1 preS2 specific. Taken together, all these results suggest that the preS1 antigen may function as a strong T cell immunogen in man.

Antibodies to glutaraldehyde-polymerized human albumin (anti-pHSA) in viral hepatitis

The antibody to polymerized human albumin (anti-pHSA) was studied in normal subjects and in the course of infection from hepatitis A virus, hepatitis B virus, and hepatitis non-A, non-B virus. Results show that anti-pHSA antibody was never found in normal subjects, but it appeared during virus liver pathologies. The behavior of anti-pHSA differs in acute type A hepatitis that does not change to chronic form and in those forms which tend to become chronic (B and nonA, nonB). In the type-A infection anti-pHSA disappears after the acute phase; in the other two forms it persists all along as the infection develops. Specifically in non-A, non-B infection only the IgM type anti-pHSA is produced.

Anti-pre-S antibodies in different groups of patients with hepatitis B virus infection

The anti-pre-S antibody in the samples of sera from normal healthy persons and patients with different clinical types of liver diseases due to hepatitis B virus (HBV) infection was detected by a newly established enzyme-linked immunosorbent assay technique. This test is a blocking assay where anti-pre-S antibody in the patient's serum blocks subsequent addition of horse radish peroxidase-labelled polymerized human serum albumin (pHSA) to the pHSA-receptor site of HBsAg molecules fixed on a solid surface. Anti-pre-S activity was not detected in any from 95 healthy persons who were negative for all HBV-markers or from 105 healthy HBV carriers. In 12 sera from HBV vaccine recipients, anti-pre-S activity was noted in higher proportions compared with anti-HBs, after both the second and third doses of vaccine. Anti-pre-S activity was detected in small proportions of HBsAg positive sera from acute viral hepatitis (4.2%) and chronic active hepatitis (10%). In subacute viral hepatitis patients, the anti-pre-S antibody was totally absent. However, anti-pre-S activity was recorded in high proportions of HBsAg-positive sera from patients with cirrhosis of liver (57.2%) and fulminant hepatitis (41.6%). The anti-pre-S antibodies were assumed to be implicated in the clearance of HBV particles from circulation without causing tissue damage.

Antibodies to translation products of the pre-S1 and pre-S2 regions of the envelope gene of hepatitis B virus in fulminant hepatitis B

Sera from 11 patients with fulminant hepatitis B were tested for antibodies to translation products of the pre-S1 and pre-S2 regions of hepatitis B virus of IgM, IgA and IgG classes, as well as of IgA1, IgA2 and SIgA, with solid-phase enzyme immunoassays using native viral polypeptides. Antibodies to pre-S1 region product of IgM and/or IgA class were detected invariably in six patients who still had detectable hepatitis B surface antigen in serum at the time of clinical presentation. The remaining five patients who had lost HBsAg at presentation had antibodies to pre-S region products of various immunoglobulin classes in higher titers. The five patients with fulminant hepatitis without HBsAg had higher levels of IgA antibodies to pre-S region products than the seven patients with nonfulminant acute hepatitis B who had lost HBsAg: IgA antibody to pre-S1 region product (75.6 +/- 63.8 vs. 2.9 +/- 3.2, p less than 0.01) and IgA antibody to pre-S2 region product (28.9 +/- 25.3 vs. 4.2 +/- 6.9, p less than 0.01). IgA antibodies to pre-S1 and pre-S2 region products were invariably polymeric in fulminant hepatitis B. These findings are compatible with the hypothesis that a heightened humoral antibody response to pre-S1 and pre-S2 region products occurs early during the course of fulminant hepatitis B, participating in severe hepatic injury and early clearance of virus characteristic of this disease.

The Vero cell receptor for the hepatitis B virus small S protein is a sialoglycoprotein

The Vero (African green monkey kidney-derived) cell line is capable of binding recombinant hepatitis B surface antigen (rHBsAg) particles containing only the small surface (S) protein of hepatitis B virus (HBV). This binding activity appears to be due to a single major population of receptors (M. E. Peeples et al., Virology 160, 135-142 (1987]. Since infectious HBV particles also contain the small S protein, it is possible that the Vero cell receptor might also function as an HBV receptor. The initial physical characterization of this receptor is reported here. Treatment of Vero cells with each of four proteases reduced their binding activity by 70% or greater, indicating that the receptor is partially protein in nature. Binding activity was also reduced by pretreating cells with neuraminidase or low levels of sodium periodate, indicating that sialic acid also plays a major role in the receptor activity. Consistent with this interpretation, N-acetylneuraminic acid and N-acetylneuraminyl-lactose were able to competitively inhibit rHBsAg particle attachment to Vero cells. The protein nature of the Vero cell receptor was confirmed by the demonstration that chymotrypsin treatment which resulted in 70% loss of binding had little effect on the cell sialic acid content. Therefore, the Vero cell receptor for rHBsAg particles is a sialoglycoprotein.

Receptors for polymerized human serum albumin in plasma derived hepatitis B vaccines

The presence of polymerized human serum albumin receptors (pHSA-R) in two hepatitis B virus (HBV) plasma derived vaccines (HB-Vax, Merck Sharp and Dohme; Hevac-B, Pasteur) was detected by three methods, using pHSA polystyrene coated beads and 125I-anti-HBs (method 1) and polyclonal (method 2) or monoclonal (method 3) peroxidase conjugated anti-HBs. Only a very weak reaction was found for pHSA-R in HB-Vax vaccine when the tests were performed in undiluted vaccine. No reactivity in 1/100 dilution (normally used to test pHSA-R in serum samples) was observed. In contrast, Hevac-B vaccine contained pHSA-R activity in 1/100 dilution as tested by any of the three methods. Furthermore, the level of pHSA-R detected in Hevac-B vaccine is similar to that observed in asymptomatic HBsAg carriers with the same HBsAg concentration. In summary, Hevac-B vaccine contains pHSA-R, whilst HB-Vax shows only weakly reacting pHSA-R, probably insufficient to develop anti-pHSA-R antibodies.

A synthetic peptide coded for by the pre-S2 region of hepatitis B virus for adding immunogenicity to small spherical particles made of the product of the S gene

Small spherical particles produced in the non-permissive phase of hepatitis B virus infection, when the viral genome is integrated into the chromosome of hosts, are rich in the product of the S gene, but poor in the product of the pre-S2 region. For the purpose of adding immunogenicity to spherical particles deficient in the pre-S2 region product, they were conjugated with a synthetic peptide of 19 amino acid residues. The peptide reproduced a hydrophilic area of the pre-S2 region product encoded by viral genomes of subtypes adr, ayw and ayr. The spherical particles supplemented with the pre-S2 peptide raised antibody to the pre-S2 region product in mice, in addition to antibody to the product of the S gene. Antibody to pre-S2 region product, prepared from sera of immunized mice by absorption with the S gene product, bound to spherical particles bearing pre-S2 region product, irrespective of adr, adw, ayw or ayr subtype, and agglutinated hepatitis B virions in immune electron microscopy. Based on the results obtained, the synthetic peptide may prove useful in adding protective efficacy to small spherical particles poor in pre-S2 region product.

A solid-phase enzyme immunoassay for the determination of IgM and IgG antibodies against translation products of pre-S1 and pre-S2 regions of hepatitis B virus

The envelope of hepatitis B virus is coded for by pre-S1, pre-S2 regions and the S gene. A method was developed to determine antibody to the product of pre-S1 region (anti-pre-S1) and antibody to the product of pre-S2 region (anti-pre-S2), either of IgM or IgG class, by a solid-phase enzyme immunoassay. For the determination of anti-pre-S1, tubular particles containing translation products of pre-S1, pre-S2 regions and the S gene were broken into constituent envelope polypeptides and immobilized on a solid support. Serums were absorbed with spherical particles containing translation products of pre-S2 region and the S gene, obtained from plasma positive for hepatitis B e antigen (HBeAg) and deprived of particles carrying pre-S1 product by an affinity column. They were then tested for the binding with tubular polypeptides fixed on a solid support, and the bound antibody representing anti-pre-S1 was detected by monoclonal antibody to human IgM/mu or IgG/gamma labeled with horseradish peroxidase. For the determination of anti-pre-S2, test serums were absorbed with spherical particles containing the product of the S gene, obtained from plasma positive for antibody to HBeAg and deprived of particles bearing pre-S2 product by an affinity column. They were then tested for the binding with polypeptides, fixed on a solid support, composed of products of pre-S2 region and the S gene. The assay was applied to the determination of anti-pre-S1 and anti-pre-S2 of IgM or IgG class in asymptomatic carriers and in persons who had recovered from infection with hepatitis B virus.

Demonstration of pre-S polypeptides of hepatitis B virus in infected livers

The large (pre-S1), middle (pre-S2) and major (P24) polypeptides of HBsAg have been defined in detail, but their role in hepatitis B virus infection is not known. Therefore, we studied the expression of pre-S1, pre-S2 and P24 in the liver of 15 patients with acute or chronic hepatitis B virus infection using monoclonal and polyclonal antibodies in a double staining immunofluorescence method. The pre-S and major HBsAg polypeptides were co-expressed in the hepatocyte cytoplasm of all patients except for one case of chronic active hepatitis and cirrhosis. HBcAg was present in hepatocyte nuclei of nine patients suggestive of active hepatitis B virus replication. These studies support the hypothesis that the pre-S polypeptides represent essential components of the envelope of hepatitis B virus.

Antibody to the receptor for polymerized human serum albumin in acute and persistent infection with hepatitis B virus

The antibody against the receptor for polymerized human serum albumin was determined by radioimmunoassay. The method involved the inhibition by the test serum, absorbed with HBsAg particles without the receptor, on the binding of polymerized human serum albumin to HBsAg particles with the receptor fixed on a solid support. The amount of polymerized human serum albumin captured by the receptor on HBsAg was then determined by the radiolabeled monoclonal antibody directed to an epitope specific for polymerized human serum albumin. In acute infection, the antibody to the receptor for polymerized human serum albumin appeared in the early recovery phase while HBs antigenemia and elevated transaminase levels were still present, preceding the antibody to HBsAg (anti-HBs). The antibody was detected in 4 (1%) of 358 sera from asymptomatic carriers of HBsAg containing antibody to HBeAg, and in none of 67 sera containing HBeAg. Although the antibody was found in as many as 111 (74%) of 150 sera from blood donors who had presumably acquired anti-HBs after natural infection, it was not detected in any sera from 77 recipients of hepatitis B vaccine who had seroconverted for anti-HBs. On the basis of these observations, the determination of antibody to the receptor for polymerized human serum albumin helps in further understanding the immunity to hepatitis B virus.