Hepatitis B antigen: antigenic sites related to human serum proteins revealed by affinity chromatography

Activity of nucleic acid polymers in rodent models of HBV infection

Nucleic acid polymers (NAPs) block the release of HBsAg from infected hepatocytes. These compounds have been previously shown to have the unique ability to eliminate serum surface antigen in DHBV-infected Pekin ducks and achieve multilog reduction of HBsAg or HBsAg loss in patients with chronic HBV infection and HBV/HDV coinfection. In ducks and humans, the blockage of HBsAg release by NAPs occurs by the selective targeting of the assembly and/or secretion of subviral particles (SVPs). The clinically active NAP species REP 2055 and REP 2139 were investigated in other relevant animal models of HBV infection including woodchucks chronically infected with WHV, HBV transgenic mice and HBV infected SCID-Hu mice. The liver accumulation of REP 2139 in woodchucks following subcutaneous administration was examined and was found to be similar to that observed in mice and ducks. However, in woodchucks, NAP treatment was associated with only mild (36-79% relative to baseline) reductions in WHsAg (4/10 animals) after 3-5 weeks of treatment without changes in serum WHV DNA. In HBV infected SCID-Hu mice, REP 2055 treatment was not associated with any reduction of HBsAg, HBeAg or HBV DNA in the serum after 28 days of treatment. In HBV transgenic mice, no reductions in serum HBsAg were observed with REP 2139 with up to 12 weeks of treatment. In conclusion, the antiviral effects of NAPs in DHBV infected ducks and patients with chronic HBV infection were weak or absent in woodchuck and mouse models despite similar liver accumulation of NAPs in all these species, suggesting that the mechanisms of SVP assembly and or secretion present in rodent models differs from that in DHBV and chronic HBV infections.

Prophylactic vaccination against hepatitis B: achievements, challenges and perspectives

Large-scale vaccination against hepatitis B virus (HBV) infection started in 1984 with first-generation vaccines made from plasma of chronic carriers containing HBV surface antigen (HBsAg). Thereafter, it was replaced in most countries by second-generation vaccines manufactured in yeast cells transformed with gene S encoding HBsAg. Both generations of vaccines have been applied for universal neonate and early childhood vaccination worldwide and have led to a 70-90 % decrease in chronic HBV carrier rates. However, 10-30% of newborns from HBsAg/HBeAg-positive mothers cannot be protected by passive/active vaccination alone and become chronic HBV carriers themselves. Asymptomatic occult HBV infections are frequent even in those who have protective levels of anti-HBs. Suboptimal protection may be due to heterologous HBsAg subtypes that are present in 99% of HBV carriers worldwide. Second-generation vaccines contain partially misfolded HBsAg and lack preS1 antigen that carries the major HBV attachment site and neutralizing epitopes. Third-generation vaccines produced in mammalian cells contain correctly folded HBsAg and neutralizing epitopes of the preS antigens, induce more rapid protection, overcome nonresponse to second-generation vaccines and, most importantly, may provide better protection for newborns of HBV-positive mothers. PreS/S vaccines expressed in mammalian cells are more expensive to manufacture, but introduction of more potent HBV vaccines should be considered in regions with a high rate of vertical transmission pending assessment of health economics and healthcare priorities. With optimal vaccines and vaccination coverage, eradication of HBV would be possible.

Interaction between hepatitis B surface proteins and monomeric human serum albumin

HBsAg is known to bind to human serum albumin polymerized by glutaraldehyde, human serum albumin has been found in preparations of HBsAg by several investigators. However, it is not yet known whether natural human serum albumin binds to hepatitis B virus under physiological conditions. We studied the binding between natural or recombinant HBsAg and monomeric human serum albumin by immunological, biochemical and biophysical methods. The binding capacity of 20-nm HBs spheres was variable but ranged up to six molecules HSA/sphere. A reversible binding site for human serum albumin was exclusively localized in the preS2 domain, whereas the S domain was inactive in vitro. Human serum albumin copurified with HBsAg of human origin during gel chromatography or sucrose-gradient centrifugation. This human serum albumin was monomeric in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The preS2-bound part of the human serum albumin could be removed from HBsAg by high-salt, such as CsCl centrifugation, but another part could only be removed by treatment with a disulfide cleaving reagent. Most of this covalently bound human serum albumin was retained at the HBsAg particle after complete cleavage of medium-sized HBs protein with trypsin. This indicates a second way in which albumin binds irreversible to cysteine(s) of the small HBs protein (SHBs, P24 and GP27).

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.

Characterisation of the polymerised and monomeric human serum albumin binding sites on hepatitis B surface antigen

Receptors for polymerised human albumin are present on the pre-S sequence of the envelope protein of HBV and on the hepatocyte membrane and are thought to be involved in uptake of the virus by hepatocytes. Using a solid phase radioimmunoassay we demonstrate binding of HBsAg to polymerised human serum albumin (pHSA) in both HBe antigen-positive and -negative patients, and this binding is linearly related to the HBsAg titre in both groups. There are probably several modes of interaction between HBsAg and pHSA. Here we show that pHSA binds to the 22,000-dalton polypeptide of HBsAg, which does not contain the pre-S sequence. This pHSA-HBsAg interaction is inhibited by physiological concentrations of human serum albumin, suggesting that the albumin known to be present in the envelop of HBsAg plays a role in this binding. The inhibition of pHSA/HBsAg interaction by native albumin suggests that this interaction is probably not an important mechanism of virus uptake during infection of hepatocytes.

Response to a hepatitis B polypeptide vaccine in micelle form in a young adult population

Polypeptide micelles with relative molecular weights of 25,000 (p25) and 30,000 (gp30) daltons were prepared from native 22-nm hepatitis B surface antigen (HBsAg) particles. This p25/gp30 complex was alum-adsorbed, and three dosage levels (20 micrograms, 4 micrograms, and 0.8 micrograms) were administered at 0, 1, and 6 months to 51 human volunteers. Local and systemic reactions were clinically insignificant, and all vaccinees seroconverted, regardless of dose. As anticipated, antibody responses diminished as the dosage was reduced. Seroconversion rates and geometric mean antibody levels for the 20 micrograms dosage group were significantly better than those observed with a commercial vaccine and were comparable to those achieved after immunization with 40 micrograms of the intact 22-nm particles used to prepare the polypeptides. By 2 weeks, an anti-HBs response was elicited in 80% of the group receiving 20 micrograms of the polypeptide vaccine. This rapid response to immunization may be particularly beneficial for postexposure prophylaxis where the early development of immunity is advantageous.

Regulation of the immune response to hepatitis B virus and human serum albumin. I. Hepatitis B surface antigen-induced secretion of antibodies with specificity for human serum albumin in hepatitis B-immune donors in vitro

The circulatory pool of B cells, from donors immune to hepatitis B (HB) through natural infection, contained sensitized B cells with the capacity to secrete antibodies with specificity for human serum albumin (HSA) when stimulated with purified hepatitis B surface antigen (HBsAg) in vitro. The immunoglobulin secretion was dependent upon and regulated by T cells and specifically induced, since it was not obtained in cell cultures from HB-susceptible donors. Culture supernatants with anti-HSA reactivity also contained specific antibodies to HBsAg (anti-HBs), indicating that the outer coat of HBV normally provokes an immune response to both the viral antigen and a 'self' component. Perturbation in the regulation of the immune response triggered by HSA in association with HBV/HBsAg particles may involve a putative risk for development of chronic HBsAg carriership.

Binding activity of HBsAg particles from chronic HBsAg carriers to polystyrene beads coated with polymerized human serum albumin: diagnostic relevance of the assay

The binding activity of HBsAg particles to polystyrene beads coated with polymerized human serum albumin (pHSA) was studied by radioimmunoassay in 48 patients with chronic HBsAg carrier state. The pHSA assay was positive in all 16 HBeAg-positive patients and in 22 HBeAg-negative HBsAg carriers with chronic hepatitis. Asymptomatic, "healthy" HBsAg carriers did not react in the pHSA assay. Mean binding activity was significantly higher in the HBeAg-positive group (P/N ratio 39.3) than in HBeAg-negative carriers with chronic hepatitis in various stages (P/N ratio 19.2). Fractionation of five representative HBeAg-positive sera by density gradient ultracentrifugation in cesium chloride yielded three peaks of HBsAg particles at 1.28, 1.22 and. 1.18 g/ml. The first HBsAg peak contained Dane particles and exhibited strong reactivity in pHSA assay. The second and third peaks, both consisting of 22 nm particles, reacted differently in pHSA assay. While about half of the HBsAg particles in the second peak were bound, reaction in the third HBsAg peak was predominantly negative. Intrahepatic HBsAg was detectable with the immunofluorescence technique in 19 of 22 HBsAg carriers. HBcAg was found in seven of 10 HBeAg-positive cases and in three of 16 HBeAg-negative patients with chronic hepatitis. The diagnostic value of pHSA assay might be seen in differentiation between HBeAg-negative chronic HBsAg carriers with liver disease or "healthy" carrier state.

H-2 linked genetic control of immune responsiveness to hepatitis B surface antigen (HBsAg) in mice

Recent data suggest that genes involved in the control of (1) immune responses of humans to HBsAg and (2) the susceptibility to the development of chronic hepatitis B are linked to the major HLA histocompatibility complex. Studies on the genetic regulation of anti-HBs responses and on the possible abrogation of nonresponsiveness to HBsAg in humans are difficult. In an attempt to develop a relevant animal model system, the anti-HBs response of inbred and congenic strains of mice was investigated. A great variation in anti-HBs responses among individual mice belonging to the same strains was observed. Nevertheless, it was possible to rank the inbred mouse strains studied according to their decreasing anti-HBs responses as follows: BALB/c[d] congruent to SWR/J[q] greater than C57BL/6J[b] congruent to DBA/2J[a] greater than AKR/J[k] greater than A/J[a] greater than CBA/CaJ[k] greater than SJL/J[s]. (Letters in brackets indicate H-2 haplotype). Only a small proportion of SJL mice had an anti-HBs response. Therefore, this strain may serve as a model for human nonresponders. Studies with the congenic strains B10.D2[d] and B10.S[s] indicated that genes conferring responsiveness to HBsAg are linked to the H-2 histocompatibility complex. However, genes not linked to H-2 also probably play a role in regulating anti-Hbs responses.

Specificity of hepatitis B virus affinity for human hepatic tissue

Using radiolabeled purified hepatitis B surface antigen and human liver slices, the affinity of hepatitis B virus to its host organ was evaluated. Saturable adsorption of the 125I-HBs Ag complex to liver was demonstrated over both time and complex concentration which could be blocked by excess unlabeled antigen. The specific binding was not found using human pancreas, lung, or kidney tissue. Correspondingly, no specific binding could be found for murine liver but it could be demonstrated with woodchuck liver. The woodchuck is a natural host for one of the newly described hepatitis B-like viruses which is antigenically cross-reactive with the B virus.

Hepatitis B polypeptide vaccine preparation in micelle form

The immunoprophylaxis of hepatitis B is hampered by the lack of a technique for growing hepatitis B virus (HBV) in tissue culture. Plasma from persistently infected individuals, one source of viral antigen, contains characteristic 22-nm spherical particles which share a common antigen (the hepatitis B surface antigen or HBsAg) with the outer envelope of the 42-nm double-shelled DNA virus. Highly purified inactivated 22-nm particles have been shown to be safe and to confer protective immunity against HBV in a recent large-scale clinical trial. We have already described the extraction from the particles of a complex of two proteins which are antigenic determinants of HBV--the polypeptide with molecular weight (MW) between 22,000 and 24,000 (called p23) and the glycosylated polypeptide (called gp28) with MW in the range 26,000--29,000 which is thought to be the glycosylated form of p23. We now report the preparation from this complex of water-soluble protein micelles which may be a suitable basis for a second-generation hepatitis B vaccine.

Interactions between polymerized human albumin, hepatitis B surface antigen, and complement: I. Binding of polyalbumin to Clq

There is considerable evidence that substances other than immunoglobulins can bind human Clq. Utilizing purified human Clq immobilized on polystyrene beads, we have demonstrated that polymerized human albumin (PHALB-125I) binds to human Clq in a direct binding assay. This interaction required a high degree of albumin polymerization as the percentage of binding was proportional to the polymer size and monomeric albumin was unreactive. Binding was species specific in the human Clq bound only human, and not xenogeneic, polyalbumins. Similarly, polymers of various other human plasma proteins were unreactive. To demonstrate that this interaction was not unique to immobilized Clq, soluble Clq was shown to inhibit PHALB-125I binding to solid phase Clq. Because aggregated IgG, poly(I):poly(C), dextran sulfate, polyglutamic acid, and polylysine have been previously shown to bind Clq, we used them in further blocking experiments and found them also to inhibit the interaction between Clq and PHALB. Anti-human Clq and, to a lesser extent, anti-PHALB antibodies inhibited the interaction. The Clq-PHALB binding was pH, ionic strength, and temperature dependent. In addition, human Clq was not observed to bind hepatitis B surface antigen (HBsAg) directly; however, in the presence of sufficiently polymerized human albumin a Clq-PHALB-HBsAg complex was formed. These interactions may be implicated in hepatocyte-HBsAg receptor function as well as in the host defense mechanisms involved in hepatitis B virus infection.

Interactions between polymerized human albumin, hepatitis B surface antigen, and complement: II. Involvement of Clq in or near the hepatitis B surface antigen receptor for polyalbumin

A species-specific receptor for polymerized human albumin (PHALB) has been reported on hepatitis B surface antigen (HBsAg)-carrying particles. Our previous observations that human Clq also binds PHALB in a species-restricted manner led us to investigate the possibility that HBsAg-associated Clq is involved in the PHALB receptor on HBsAg particles. The temperature, ionic strength, and pH requirements necessary for binding of PHALB to both Clq and HBsAg were compared and found to be similar. Normal human serum and purified Clq inhibited the PHALB-HBsAg interaction; the inhibition was markedly reduced in heat-inactivated and Clq-depleted serum. Heat-denatured or reduced and alkylated Clq failed to inhibit the PHALB-HBsAg binding. Moreover, human Clq was found to be present in purified preparations of HBsAg and the quantity detected paralleled the degree of PHALB-HBsAg binding. While anti-Clq inhibited the PHALB-HBsAg interaction, anti-Clr, - Cls, -C3, and -Ig were not inhibitory. Collagenase treatment of purified HBsAg reduced both PHALB-binding activity and the degree of HBsAg-associated Clq. These observations provide evidence that HBsAg-associated Clq is involved in or near the HBsAg-binding site for PHALB.

A method for the automated screening for hepatitis B surface antigen

A reverse passive hemagglutination (RPHA-G) technique for the automated screening of hepatitis B surface antigen (HBsAg) on the Groupamatic 360 (Kontron International, Zürich, Switzerland) has been developed. It is more sensitive than manual RPHA (RPHA-M) and nearly as sensitive as radioimmunoassay (RIA); it detects 6 ng/ml of HBsAg, compared to 3 ng/ml by RIA and 25 ng/ml by RPHA-M. Although it is slightly inferior to the other two methods in respect of specificity, the incidence of false-positive reactions was only 0.34%. The test can also be performed manually without the Groupamatic.

Relationship of large hepatitis B surface antigen polypeptide to human serum albumin

A significant proportion (20 to 40%) of highly purified 22-nm hepatitis B surface antigen (HBsAg) particles contain human serum albumin (HSA) as demonstrated by specific precipitation of radioiodinated particles by anti-HSA. Preparations of the isolated major HBsAg polypeptides (P-1, P-2, and P-6) were iodinated and analyzed by radiommunoprecipitation for reactivity with rabbit antisera to human plasma proteins. Only the P-6 fraction (molecular weight, 68,000) was precipitated and only by anti-HSA; specific precipitation was observed with guinea pig antisera to P-6 and native HBsAg and goat or rabbit antisera to HSA. Coprecipitation of P-6 with antiserum to HBsAg and with anti-HSA, compared to precipitation with each antiserum alone, indicated that the HBsAg and HSA determinants were on separate molecules. The P-6 polypeptide may represent a precursor protein of the hepatitis B virion.

Antibodies as immunological probes for studying the denaturation of HBsAg

Radioimmunoassays were developed for antibodies to denaturated forms of HBsAg (reduced and alkylated in an isotonic buffer (RAHBs) or in 8 M urea-HBs) or reduced in 8M urea but not alkylated). These tests revealed that intact HBsAg and RA-HBs shared common antigenic determinants, termed Re[Imai et al, 1974]. Anti-Re is elicited in the course of immune response to intact HBsAg in humans and experimental animals. Denaturation in 8 M urea and alkylation causes the appearance of additional antigenic determinants, the specificity of which is affected by the reagent used for alkylation. Reduction in 8 M urea followed by treatment with iodoacetate reveals antigenic sites common for HBsAg and some human serum proteins. Antibodies specific for the Le Bouvier determinants of HBsAg are probably not the appropriate probe for detection of primary translational products of the hepatitis B virus genome.

The hepatitis B virus and its DNA polymerase: the prototype three-D virus

The hepatitis B virus (HBV), the causal agent of serum hepatitis, has a diameter of 42 nm and is comprised of an outer surface coat and a 27 nm core. A unique DNA-dependent DNA polymerase is associated with the core of the virus. The core also houses a circular DNA that contains both double-stranded and single-stranded regions. In the endogenous reaction, the DNA polymerase repairs the single-stranded gaps of the viral DNA. The surface protein of the virus, called hepatitis B surface antigen, contains both lipid and carbohydrate, and is often present in particulate form in the blood of infected patients. In Asia and Africa HBV infection is associated with subsequent development of primary hepatocellular carcinoma. Although most patients recover completely from acute illness, the hepatitis B virus may cause chronic infection. Recently, a virus similar to human HBV was discovered in woodchucks. HBV has not yet been propagated in a cell culture system and the mode of replication of this unusual virus in hepatocytes is still moot. Although reliable therapy has not yet been provided, the problem of this world-wide infection has led to many interesting approaches to both vaccine production and anti-viral chemotherapy.

Interaction of hepatitis B surface antigen with polymerized human serum albumin

HBsAg binds to a solid-phase adsorbent consisting of polymerized human serum albumin (HSA) on glass particles. Both AD and AY antigenic subtypes of hepatitis B surface antigen (HBsAg) display this interaction. In either case, the binding to polymerized HSA is reduced in the presence of human serum, suggesting significant attachment of serum components at the locations on HBsAg particles where polymerized HSA binds. The temperature dependence of the interaction goes through a maximum above room temperature, in contrast to the increasing reaction with temperature of the HBsAg--anti-HBs antibody system. The interaction between HBsAg and polymerized HSA is discussed in relation to previous findings of HSA polymers and anti-polymerized albumin antibodies in hepatic patients. A mechanism for production of an autoimmune, antialbumin antibody condition, in association with hepatitis B virus infection is proposed.

Deeper insight into HBsAg--anti-albumin antibody correlations

The presence and titers of anti-albumin antibodies (AAA)--ie, precipitins (AA-IP) and agglutinins (AA-Aggl)--and the serum concentrations of immunoglobulins and albumin were determined in 210 asymptomatic carriers of HBsAg grouped according to HBsAg titer and subtype. A different immunologic pattern was observed in the HBsAg/ad and HBsAg/ay carriers, the results suggesting an increased aggressivity for the HBsAg/ay subtype which was evident in subjects with lower HBs antigenemia and characterized by higher concentrations of IgG and IgM and rises in AA-P titers. A positive linear correlation was found between HBsAg and AA-Aggl titers; the carriage of HBsAg/ad was associated with significant higher values of AA-Aggl than of HBsAg/ay. These subtle correlations between HBsAg titer and subtype and AAA suggest that the human serum albumin (HSA) known to exist on the HBsAg particles may be similar in a modified form, to that representing AAA specificity.

Experiences with radioimmunoassay in the detection of HBsAg in the presence of anti-HBs

Interference from anti-HBs present during hepatitis B antigenemia caused the appearance of several false negative reactions in a competition radioimmuno-precipitation procedure. The results indicate that such interference is considerably less in the solid-phase radioimmunoassay (Ausria II) and probably causes few false negative tests. The use of pepsin treatment as a means to destroy interfering antibodies is discussed.

Antigenic sites related to human serum proteins in HBsAg: isolation from normal human serum of a high-molecular-weight glycoprotein reacting with antialbumin

A novel minor constituent was isolated from normal human serum by affinity chromatography on columns of insolubilized concanavalin A and antibodies to albumin, followed by rate zonal centrifugation. This component has the following properties: a sedimentation coefficient of approximately 31; a diameter of 14--22 nm, and a buoyant density of 1.302 gm/cu cm. It contains about 1% neutral sugars and is electrophoretically heterogeneous, since two populations of particles with isoelectric points of pH 4.95 and 5.75 were separated by isoelectric focusing. It contains a single major glycopeptide with an apparent molecular weight of 72,000 daltons. Its amino acid composition is distinct from that of albumin. It elicited the formation of antibodies that also reacted with HBsAg.

Association of normal serum protein antigens with chimpanzee hepatitis B surface antigen particles

HBsAg/adw was purified from 2.6 liters of pooled plasma from a single chimpanzee carrier by polyethylene glycol (PEG) precipitation followed by isopycnic and rate zonal centrifugation. The different morphological populatilons of HBsAg separated in the final rate zonal centrifugation step were combined into seven pools: two fractions rich in filaments and Dane particles, two pools composed of filaments and 20--28-nm spheres, and three fractions containing mostly 20--28-nm spheres. The purified preparations of HBsAg analyzed for normal serum protein contaminants revealed albumin and traces of IgG. The same samples analyzed after Tween-80 treatment, revealed enhanced quantitites of the previous two contaminants, and in addition, transferrin, traces of alpha2-macroglobulin, IgM, and complement (C3/C3c). The residual contaminants were mostly removed by further purification and fractionation after detergent treatment using zone convection electrofocusing and rate zonal centrifugation. Our findings indicate that conventional purification techniques will not provide preparations of HBsAg free of traces of serum protein contaminants. Many of these are released only by detergent treatments and subsequent purification. It is not yet clear whether detergents release these contaminants from the interior of the particles or from firm association or incorporation within the membranes.

Hepatitis B. Cytologic localization of virus antigens and the role of the immune response

Antigens of the hepatitis B virus have been localized within liver tissue by various immunologic, histochemical, and electron microscopic methods. The abundance and distribution of these virus antigens are in part determined by the host immune response. This interaction of immune mechanisms with the hepatitis B virus may be related to the pathogenesis and natural history of human hepatitis B virus infection.

Preparative immunoabsorption electrophoresis

A method for separating a component from a mixture of antigens is described. The component which may be a virus or subfraction of a virus, is isolated by driving the mixture by electrophoresis through a gel containing precipitating antibodies directed against the unwanted components. The method is illustrated by the isolation of hepatitis B antigen from whole serum and by the separation of wild cucumber mosaic virus from a strain of tobacco mosaic virus.

Host specificity of a serum marker for hepatitis B: evidence that "e antigen" has the properties of an immunoglobulin

A family of antigens, referred to collectively as e antigen (eAg), has been detected in sera of some individuals with liver disease who test positive for hepatitis B surface antigen. Studies on eAg partially purified by affinity chromatography on insolubilized antibodies to eAg revealed the following: (i) eAg has the physicochemical and immunologic properties of an immunoglobulin, predominantly of the IgG4 subclass, and (ii) specific antigenic sites, designated as e determinants, differentiate eAg from other immunoglobulins. We suggest that these determinants represent idiotypic determinants on antibodies that are formed in response to hepatitis B virus infection and that block the host's immune surveillance mechanisms by which virus proliferation is stopped.

Immunisation against hepatitis B in man

An inactivated vaccine against hepatitis B was prepared from blood-donor HBs antigen purified on immunoadsorbents. Its safety and efficacy were tested in chimpanzees. Vaccination was then applied in an attempt to protect patients and staff in a haemodialysis unit. The efficacy of the vaccine in man was assessed by observing humoral and cellular immune reactions and by comparing changes in HBs antigenaemia in vaccinated and non-vaccinated subjects. The results indicate that this vaccine protects against hepatitis B in the circumstances in which it was administered.

Hepatitis-B: a review

The recent literature on various aspects of hepatitis-B is reviewed with emphasis on the interrelationships of viral structure, antigenic components, and host immune response in acute, chronic, and asymptomatic carrier states of the infection. The mode of replication and mechanisms of transmission are discussed. Special attention is paid to potential non-parenteral routes of spread. The role of hepatitis-B in associated immune complex diseases and in hepatoma is outlined. A guide to the interpretation of serologic tests for hepatitis-B associated antigen and antibody patterns is presented in relation to the clinical stage and prognosis of the infection. Therapy, except in conceptual terms, is not covered but a summary of the current status of active and passive immunization is given. The unresolved question of the infectivity of carrier medical staff for their patient contacts, and the reverse, is discussed.

Mechanisms responsible for defective human T-lymphocyte sheep erythrocyte rosette function associated with hepatitis B virus infections

The expression of selected lymphocyte surface-membrane markers was evaluated in 37 patients with acute viral hepatitis B, 10 of whom were studied serially through the resolving and convalescent phases of disease. Bone marrow-derived (B) lymphocytes were identified by reference to surface immunoglobulin, whereas normal thymus-derived (T) lymphocytes were assayed by their capacity to form spontaneous nonimmune rosettes with sheep erythrocytes (E rosettes, ER). During the acute and resolving phases of viral hepatitis B, the relative and absolute number of ER-positive lymphocytes was significantly reduced, whereas the number of surface immunoglobulin-positive lymphocytes and the absolute lymphocyte count remained normal. This resulted in the appearance of a third population of cells, deficient in respect to both surface immunoglobulin and ER markers. Such cells accounted for nearly 25% of peripheral blood lymphocytes, approximately 5 x 105ml blood. Depression of the number of ER-positive lymphocytes occurred at least once during the course of disease in every patient studied serially, and was observed in 55 of 67 individual assays of the 37 cases of acute viral hepatitis B. Lymphocytes from some patients reacquired ER function when cultured in fetal calf serum but not in the presence of autologous serum. Such autologous serum was capable of suppressing ER function of lymphocytes from normal donors. The extrinsic suppression of er function by a serum factor (designated as the Rosette Inhibitory Factor), was found to be time dependent, characterized by a 4-h latent period and requiring approximately 18 h for maximum attenuation of ER function. The Serum Rosette Inhibitory Factor was: (a) heat and freeze-thaw stable, (b) nondialyzable, (c) physically separable from hepatitis B surface antigen, (d) not a lymphocytotoxic antibody, and (e) had the buoyant density of a lipoprotein. This extrinsic mechanism was observed in 41.8% of patients with reduced numbers of ER-positive lymphocytes. The Rosette Inhibitory Factor was not detectable in the serum of the remaining 58.2% of the cases of acute and resolving viral hepatitis B despite the presence of reduced numbers of ER-positive lymphocytes. The lymphocytes from these cases did not reacquire ER function when cultured in the absence of autologous serum. The mechanisms responsible for the suppression of normal ER function in these cases appears to be intrinsic to the lymphocytes and not the result of a humoral factor. The T lymphocyte lineage of cells deficient in respect to ER function, whether of intrinsic or extrinsic type, was demonstrated by their capacity to form spontaneous rosettes with neuraminidase-treated sheep erythrocytes. Both intrinsic and extrinsic suppression of T lymphocyte ER function commonly occurred during the first 4 wk of acute viral hepatitis B.9 of the 10 patients followed serially continued to manifest defective ER function at 12 wk...

Integrator enzyme hypothesis for replication of hepatitis-B virus

A hypothetical model for the replication of hepatitis-B virus is presented. It is suggested that the D.N.A. polymerase associated with Dane particles facilitates integration of viral D.N.A. into the genome of the liver cell. The viral D.N.A. is then replicated with the host genome. The hypothesis accounts for certain curious experimental and clinical observations and makes several predictions which are amenable to laboratory investigation.

Cell-mediated immunity in guinea pigs to subunits derived from hepatitis B surface antigen

Guinea pigs immunized wit- hepatitis B surface antigen (HBSAg), types adw and ayw, and with two polypeptides (400,000 and 24,000 molecular weight) developed cell-mediated immunity (CMI), as determined by radioimmunoassay. Peritoneal exudate (PE) cells from guinea pigs immunized with the 40,000-molecular-weight polypeptide migrated poorly (30 to 88% inhibition) after challenge with the immunizing subunit or with purified HBSAg, type gdw or ayw. Response of the same PE cells to the 24,000-molecular-weight subunit was significantly reduced. Similar but less striking evidence for CMI was observed was PE cells derived from guinea pigs inoculated with purified type-specific HBSAg or with the 24,000-molecular-weight polypeptide. Humoral responses were predictable and showed a reasonable degree of correlation with the CMI response. PE cells from control animals inoculated with normal human serum or polyacrylamide gel were not inhibited after challenge with purified preparations of HBSAg or with the 400,000-molecular-weight polypeptide, but did show CMI with their respective immunogens. In addition, PE cells from guinea pigs inoculated with normal human serum were inhibited from migrating after challenge with the 24,000-molecular-weight subunit, suggesting that the latter may contain an antigenic determinant related to a human serum protein.

Production of antibody to individual polypeptides derived from purified hepatitis B surface antigen

Purified preparations of hepatitis B surface antigen (HBsAg) were solubilized with sodium dodecyl sulfate and urea under reducing conditions and subsequently fractionated by preparative sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis (PAGE). Pools of the individual fractions eluted from the preparative PAGE were concentrated and purified further by analytical PAGE. Five purified polypeptides were isolated from HBsAg, types adw and ayw, with molecular weights of 19,000, 24,000, 27,000, 35,000, and 40,000. Each preparations was emulsified in Freund complete adjuvant and injected into guinea pigs. Antibody to each HBsAg type was measured by radioimmunoassay. The 19,000 molecular weight polypeptide derived from ayw particles and the 27,000 molecular weight subunit obtained from both types failed to elicit an antibody response. The other three polypeptides derived from the ayw particles elicited group-specific antibody responses. Similar group-specific reactivities were observed in the testing of anti-adw 35,000 and anti-adw 40,000 molecular weight polypeptide sera. However, guinea pigs immunized with the 19,000 and the 24,000 molecular weight polypeptides of the adw type produced antibody that reacted preferentially with adw particles. This indicates that either these subunits carry predominately d determinants or that, because of the low levels of material used for inoculation, no immune response or an undetectable one was elicited to the a or w components.

Interaction of hepatitis B surface antigen (Australia antigen) with membrane vesicles of Pseudomonas aeruginosa

A lysogenic strain of Pseudomonas aeruginosa was cultured from the dialysis fluid of a patient on chronic hemodialysis treatment whose blood contained hepatitis B surface antigen (HB8Ag). When this bacterium was incubated for 4 to 7 days with serum containing HB8Ag or with purified HB8Ag, a loss of the HB8Ag-specific immunological reactivity was observed. Bacteriophages can be induced from the isolated P. aeruginosa with mitomycin C; the phages, after purification on CsCl gradients, also lyse P. aeruginosa strain 25102 (ATCC). Subsequent to gradient centrifugation of the lysate, a fraction was found with a density around 1.40 g/ml that inactivated HB8Ag after a 4-h incubation at 37 C as determined by counterelectrophoresis and hemagglutination inhibition. The activity was not found in appreciable amounts in other gradient fractions. The electron microscope shows that the active fraction contains envelope vesicles of 45 to 60 nm in diameter. In spite of their loss in HB8Ag activity, the HB8Ag particles (22nm) appeared morphologically intact. These findings suggest that an enzyme(s) is present in the vesicle fraction which inactivates antigenic determinants on HB8Ag particles. Thus, the presence of these bacteria in environments such as feces, dialysis tanks, and contaminated drinking water may prevent the detection of HB8Ag.