Occurrence of pre-S1 antigen in viremic and nonviremic carriers of hepatitis B surface antigen

The proteins of viral envelope, encoded by the pre-S1 region of HBV-DNA, were measured quantitatively with enzyme immunoassay using monoclonal antibodies directed to pre-S1 epitope and correlated with the expression of pre-S2 region encoded epitope and other HBV markers. In acute HBV infection, both pre-S encoded proteins were detected in sera along with markers of viral replication and disappeared shortly before complete virus clearance while high HBsAg titers were still present. Pre-S1 antigen was present in most (95.5%) symptomatic and asymptomatic chronic HBsAg carriers. There was no correlation between the presence of pre-S1 and HBeAg or HBV-DNA in serum: 73% of sera with pre-S1 determinants were anti-HBe positive, and only 25.4% were positive for HBV-DNA. Most pre-S1 activity in sera of viremic carriers was detected in fractions of sucrose gradient containing subviral 22-nm particles, and much less in those containing infectious virions. In asymptomatic, nonviremic HBsAg carriers, pre-S1 was located only on subviral 22-nm forms. Pre-S1 positive particles had no accessible pre-S2 epitope, which is recognized specifically by monoclonal anti-pre-S2 (F124) antibody. These results show that the synthesis of the large protein of HBV envelope may occur also in the absence of active viral replication, and in these cases pre-S1 encoded sequences are on subviral particles of HBsAg. Therefore, pre-S1 is not a serologic marker of infectious virus. Disappearance of pre-S1 epitopes on HBsAg occurs only before complete clearance of the virus, and this may have potential prognostic relevance.     

Evidence for the presence of repeating antigenic determinants in the major polypeptides derived from hepatitis B surface antigen

The immunogenicity of the four major and seven minor hepatitis B surface antigen (HBsAg)-derived polypeptides was evaluated in guinea pigs and compared to that of 22-nm HBsAg particles. Both humoral and cell-mediated immune responses were determined. All antisera reacted with homologous HBsAg/ayw and P22/ayw. However, the glycosylated polypeptides (P25, P27, P31, and P52) generally elicited the most intense immune responses. At least nine polypeptides induced antibodies which also reacted with heterologous HBsAg/adw particles and P22/adw. Whole HBsAg/ayw particles induced transformation in lymphocytes obtained from guinea pigs immunized with the major or minor polypeptides. These data tend to demonstrate that all HBsAg-derived polypeptides contain in their structure the group-specific and at least one of the subtype-specific antigenic determinants, and these determinants are also exposed on the surface of the HBsAg particle. It seems possible that a limited nucleotide sequence confers the same virus specificities to most if not all of the constitutive proteins of HBsAg.     

A vaccine prepared from the 22 nm particles of surface hepatitis B antigen (HBsAg)

A method for obtaining a subunit inactivated vaccine preparation from the 22-nm particles of HBsAg is proposed. For inactivation of the residual infectious hepatitis B virus (HBV) the preparations were successively treated with 1% sodium dodecyl sulfate (SDS) and nucleases. In addition, thermal denaturation and ultraviolet irradiation of HBV DNA were used. As a control the biologic activity of a reference virus (SV40) was tested after the same treatment. The effectiveness of DNA inactivation was monitored by adding ³ H-thymidine labeled reference virus to the vaccine preparations. The purified and inactivated HBsAg was adsorbed on Al₂O₃. Antigenicity was calculated on the basis of the determination of antibody in guinea pigs immunized with various doses of the vaccine, and the release of ¹²⁵ I- HBsAg from blood and kidneys in immunized and control mice was analyzed. Possible methods of inactivation and control of HBV vaccine is discussed.     

Small vessel vasculitis caused by hepatitis B virus immune complexes: Small vessel vasculitis and HBsAg

In a comprehensive study of 80 patients with vasculitis, 4 had concurrent hepatitis B virus (HBV) infection. Polyarteritis nodosa was present in 2 and in the other 2, cutaneous vasculitis, presenting clinically as palpable or Henoch-Schönlein purpura. In one of these patients skin biopsies demonstrated granular deposits of IgM, C3, C4, and the hepatitis B surface antigen (HBsAg) and electron-dense deposits of aggregated 20-nm particles resembling HBsAg in postcapillary venules. Evidence for circulating HBsAg-immune complexes included increased serum C1q binding activity, decreased serum complement, and a cryoprecipitate containing both HBsAg and IgM anti-HBs. Aggregated 20-nm particles resembling intact HBsAg were also seen by negative staining electron microscopy of the serum cryoprecipitate. This patient fulfills all the criteria for a specific immune complex vasculitis caused by his immune response to a chronic HBV infection. These findings emphasize that HBV infection may be associated with small vessel vasculitis as well as polyarteritis nodosa, mixed cryoglobulinemia, and glomerulonephritis. A similar immune response to other viral infections may be expressed as palpable (Henoch-Schönlein) purpura also.     

A solid-phase enzyme immunoassay for the common and subtypic determinants of hepatitis B surface antigen with monoclonal antibodies

Monoclonal antibodies were raised against the common (a) as well as subtypic determinants (d, y, w and r) of hepatitis B surface antigen (HBsAg). They were applied to subtyping HBsAg by sandwiching it between antibody against a fixed on a solid-phase support and antibody against one or other of d, y, w and r, linked to horseradish peroxidase. The assay was applied to evaluate antigenic specificities of the NIH and Japanese panels composed of 44 sera containing HBsAg particles of various subtypes. HBsAg particles of a hybrid subtype, adyr, were sandwiched between monoclonal antibody against d and that against y, thereby indicating that they possessed both d and y determinants on the selfsame particle. The expression of d and y determinants on hybrid HBsAg particles was much less than that on ordinary particles of adw, adr, ayw or ayr subtype.     

Hepatitis B surface antigen particles with all four subtypic determinants: point mutations of hepatitis B virus DNA inducing phenotypic changes or double infection with viruses of different subtypes.

Hepatitis B surface antigen (HBsAg) particles carry the common determinant, a, as well as d or y and w or r subtype determinants, and are classified into the four major subtypes, i.e., adw, adr, ayw and ayr. Rare sera contain HBsAg particles with all four subtype determinants (adywr). Target sequences (nucleotides 38-550) in the S gene of hepatitis B virus (HBV) DNA in two such sera were amplified by the polymerase chain reaction. Individual amplification products were cloned in an M13 phage vector. The HBV DNA clones obtained were subtyped by determining the second letters of codon 122 and 160 for lysine (AAA/AAG) or arginine (AGA/AGG), which specify the d or y and w or r determinants, respectively. From one serum (S-63), two adw, 10 adr and 58 ayr clones were obtained. When the two adw clones and two representatives each of the adr and ayr clones were compared against each other, for the sequence of 235 base pairs representing nucleotides 295-529 in the S gene, they differed only by 0.4-2.1% (average 1.2%). These results indicated multiple point mutations of a single HBV strain of subtype ayr and co-infection of hepatocytes with the original HBV strain and its mutant of subtype adw as the mechanism for the production of HBsAg/adywr particles. From the other serum (K-45), 1 adw, 73 adr and 4 ayw clones were obtained. The adw clone and two representative adr clones differed only by 0-1.7% in the S gene sequences, but they differed by 8.5% or greater from two representative ayw clones. HBsAg/adywr particles in this serum, therefore, could be explained by double infection of hepatocytes with two HBV strains of different subtypes (adr and ayw).     

抗个体型抗体对HBV感染的免疫调节作用——用抗个体型抗体诱生抗—HBs

Jerne~([1])指出,机体对抗原的免疫反应可以通过抗体的个体型(Id)和抗个体型抗体(抗-Id)的相互作用而得到调节。这一理论陆续被许多学者的研究结果所证实。     

Characterization of hepatitis B virus (Dane particle)

Hepatitis B virions (Dane particles) were purified from the sera of chronic HBsAg carriers by consecutive rate-zonal and isopycnic centrifugations in sucrose gradients using HBsAg, HBcAg and endogenous DNA polymerase activities as specific markers. Purified Dane particles, radiolabelled with Na ¹²⁵I by the chloramine-T procedure, had a higher buoyant density in CsCl (1.28 g/cm³) than unlabelled particles (1.26 g/cm³) and an estimated sedimentation coefficient of 280 s. ¹²⁵I-Dane particles were fully precipitated by anti-HBs and not by anti-HBc sera. Heavy and light density core particles were purified from heavy and light density populations of Dane particles and radioiodinated. The iodinated polypeptides of Dane particles and HBcAg were compared with those of the iodinated 22-nm form of HBsAg by SDS-PAGE. Iodinated Dane particles contained seven polypeptides with molecular weights of 18,000, 23,000, 26,000, 34,000, 43,000, 48,000 and 115,000. Heavy and light core particles contained three polypeptides with molecular weights of 18,000, 25,000 and 37,000.     

Anti-idiotypic humoral and cellular responses to antibody to hepatitis B surface antigen in hepatitis B viral infections.

In order to investigate regulatory significance of humoral and cellular responses to the idiotypic (Id) determinants on the antibody to hepatitis B surface antigen (anti-HBs), they were studied in acute hepatitis B and in chronic HBV infection. The results were compared with humoral and cellular responses of the same patients to hepatitis B surface antigen (HBsAg). In acute hepatitis B, the responses to HBsAg, were delayed until 3-4 weeks after the onset of clinical symptoms. However, the leucocyte migration inhibition (LMI) and the lymphocyte transformation (LTT) responses to affinity purified anti-HBs were found to be evolved very early in the course of acute hepatitis B, though anti-Id antibodies were absent. The majority of chronic HBV carriers showed a poor humoral and cellular response to HBsAg. Ten out of 38 chronic carriers showed anti-Id antibodies which recognized a major cross-reactive idiotype (CRI) on the anti-HBs molecule. Twenty-five out of 38 chronic carriers also showed LMI response to the Id determinants on the anti-HBs. LMI response induced by anti-HBs could be blocked by a specific Balb/c anti-Id antibody which also recognized the CRI. Thus, in both acute and chronic HBV infections, the anti-Id humoral and cellular responses correlated with poor humoral and cellular responses to HBsAg, indicating regulatory significance.     

Development and Technical and Clinical Validation of a Quantitative Enzyme-Linked Immunosorbent Assay for the Detection of Human Antibodies to Hepatitis B Surface Antigen in Recipients of Recombinant Hepatitis B Virus Vaccine

Pending removal from the market of a commercial assay (the AUSAB [Abbott Laboratories] enzyme immunoassay [EIA]) for the determination of antibodies to hepatitis B surface antigen (HBsAg), a new in-house quantitative enzyme-linked immunosorbent assay (ELISA) to measure antibodies against HBsAg (anti-HBs) was developed (anti-HBs in-house). Specific anti-HBs antibodies were sandwiched between the precoated HBsAg ad and ay subtypes purified from plasma from hepatitis B virus (HBV) human carriers and the recombinant HBsAg adw2 subtype tagged with horseradish peroxidase. The assay was calibrated against the 1st International Reference Preparation for anti-hepatitis B immunoglobulin (lot 1977-W1042). Analytical sensitivity and the limit of quantitation were estimated at 0.43 mIU/ml and 2.0 mIU/ml, respectively. Overall reproducibility was 11.86%, and accuracy was estimated to be 94.89%. More than 4,000 samples from seven clinical trials were tested with the anti-HBs in-house assay and compared to results generated with AUSAB EIA and AUSAB radioimmunoassay (RIA). During the technical validation, the anti-HBs in-house assay was compared to the AUSAB RIA as a reference (n = 919). Overall assessment of concordance and Deming''s regression analysis were performed. The coefficient of correlation between the AUSAB RIA and anti-HBs in-house assay was 0.9815 with a slope of 0.9187. The overall agreement between anti-HBs in-house and AUSAB RIA was 97.61%, considering the clinical cutoffs at 3.3 mIU/ml and 1.0 mIU/ml for the respective assays. From a clinical perspective, seroprotection rates and anti-HBs geometric mean antibody concentrations for individual studies calculated with either the in-house assay or the reference assays were similar. Conclusions of individual studies were confirmed. The performance characteristics of the in-house assay are acceptable. There is no evidence that use of the new assay would lead to different clinical conclusions from the reference method.Hepatitis B infection is a global health problem but most acutely affects developing countries (16). Currently there is no effective therapy against hepatitis B, whose disease spectrum ranges from asymptomatic disease to chronic liver diseases, including cirrhosis and hepatocellular carcinoma. Prevention of the illness through vaccination remains the method of choice for its control and eradication. Active immunization against hepatitis B infection can be achieved using vaccines containing either inactivated hepatitis B virus (HBV) surface protein (HBsAg) physicochemically purified from plasma from HBV human carriers or recombinant surface antigen produced by transfer of the S gene of HBV coding for HBsAg to an appropriate plasmid that is then inserted into the desired expression vector. The recombinant vaccine manufactured by GlaxoSmithKline Biologicals (GSK) is produced in yeast and is antigenically similar to plasma-derived HBsAg (4). Clinical studies of this recombinant vaccine either formulated as a single-component vaccine (Engerix-B; trademark of GSK) or formulated in combination with other antigens such as hepatitis A vaccine (Twinrix; trademark of GSK) or pediatric diphtheria-tetanus-pertussis-based vaccines (such as Infanrix hexa and Tritanrix HepB; trademarks of GSK) have proven its efficacy and immunogenicity (5).To date, commercial assays from Abbott Laboratories have been used at GSK to quantify the immune response to HBV vaccines in terms of antibodies against HBsAg (anti-HBs). However, since these assays are no longer commercially available in Europe, GSK has developed an in-house assay with adequate technical and clinical performance to ensure long-term supply of an assay with consistent quality. This paper describes the development, technical validation, and the clinical assessment of the new anti-HBs in-house assay.     

A hepatitis B virus variant found in the sera of immunised children induces a conformational change in the HBsAg "a" determinant.

The emergence of variants in the outer envelope proteins of hepatitis B virus (HBV) are found among individuals vaccinated against HBV and asymptomatic carriers of the infection. For example, children in The Gambia vaccinated against hepatitis B may show serological evidence of breakthrough infections, particularly if anti-HBs antibodies induced by the vaccine are low in titre. A single-point mutation at nucleotide 421 of the S gene is associated with such breakthrough infections. In the present study, the antigenicity of variant HBV S protein expressed as HBsAg particles in a vaccinia virus expression system has been characterised using a panel of monoclonal antibodies directed against linear and conformational determinations of the S protein. A cellular ELISA procedure using expressed antigen in Vero cells revealed differences in reactivity using four of the six antibodies that had been raised against the adw subtype of HBV and recognise conformational epitopes in the a determinant. In two instances, an enhanced reactivity for the variant antigen was found, confirming that point mutations in the a determinant of the S protein between residues 139 and 147 may result in significant changes in conformation. These findings also demonstrate that there are distinct antigenic differences between the vaccine strains of HBsAg/ adw subtype and the predominant HBsAg subtype circulating in West Africa. The implications of this work are that serodiagnosis of HBV infections may be unreliable in populations where there is a possibility of variant HBV infections emerging in the face of increasing herd immunity to HBV as a result of vaccination, particularly using monoclonal antibody-based diagnostic tests. Such variants may play a role in the maintenance of HBV infections in endemic regions.     

Immunochemical structure of the hepatitis B surface antigen vaccine--II. Analysis of antibody responses in human sera against the envelope proteins

Antibody responses to the three envelope (env) proteins of hepatitis B viral particles (HB-VP): the S-encoded P25 polypeptide; the pre-S(2)- and S-encoded GP33/GP36 polypeptide; and the large entire env gene (pre-S + S) product, P39/GP42, were investigated using a Western immunoblotting assay (WIBA). HB-VP proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and transferred to nitrocellulose by electroblotting were used as antigenic probes to determine the polypeptide specificity of these antibodies present in immune individuals. Antisera from human subjects either after a natural HBV infection or after active immunization with the hepatitis B vaccine licensed in France were selected on the basis of a positive serological RIA test for antibodies against hepatitis B surface antigen (HBsAg). In all studied cases, the lack of reactivity of the anti-HBs/P25 antibodies in blots from reduced SDS gels confirms that the S-related-determinants have a conformation sensitive to denaturing agents. In contrast, the anti-pre-S(2)/GP33-GP36 antibodies and the anti-pre-S(1)/P39-GP42 antibodies can be easily detected in WIBA, providing these antibodies recognize the disulfide-bond independent pre-S determinants on the denatured env proteins. However, antisera raised in guinea-pigs against individual HBsAg polypeptides contain antibodies reacting with denatured S-proteins, suggesting that the sequential S-determinants are lost during HBV morphogenesis. Antibody responses in HBV convalescing patients or vaccinated healthy donors are shown to be characterized by: an early transient polypeptide specific-antibody response to pre-S(2)-sequences (detected in WIBA); a persistent antibody response to conformation-dependent S-determinants (detected in RIA). This implies that effective long-term protection against HBV infection requires antibodies directed to native env proteins.     

Evaluation of murine monoclonal antibodies targeting different epitopes of the hepatitis B virus surface antigen by using immunological as well as molecular biology and biochemical approaches

The hepatitis B virus surface protein (HBsAg) displays the major B cells antigenic determinants that can induce protective immunity and prevent the hepatitis B virus (HBV) infection, a major health problem. A panel of murine monoclonal antibodies against the HBsAg (MAb anti-HBs), raised after mice immunization with a pool of plasma of hepatitis chronic carriers, has been established. Mainly using simple immunological tools such as enzyme-linked immunosorbent assay (ELISA) and Western blot analysis, we could trace the location of the epitopes on the HBsAg determinants. We also report the use of two specific methodology approaches based on molecular biology and biochemical techniques such as, respectively, cloning and expression of preS1 major neutralizing epitope of the HBsAg in Escherichia coli and ELISA accomplished to chemical reduction with dithiothreitol (DTT), which were able to complete the MAb anti-HBs characterization. Our results showed that the majority of the MAbs anti-HBs were directed to the HBV common determinant a. One MAb recognizes a discontinuous epitope present in all forms of the HBsAg when evaluated by Western blot.     

Subtyping of hepatitis B surface antigen by radioimmunoassay.

A solid-phase radioimmunoassay used for HBsAg screening of blood donors at the Finnish Red Cross Blood Transfusion Service (FRC-RIA) was modified for subtyping of HBsAg. The anti-HBs coated test tubes of FRC-RIA served as the solid-phase anti-HBs. Monospecific ¹²⁵I-labelled antibodies were prepared by absorption of the labelled anti-HBs used in FRC-RIA with partially purified HBsAg coupled to Sepharose 4B.Labelled anti-y detected 4 ng/ml of ay antigen and 160 ng/ml of ad antigen; the reagent was 40 times more sensitive for the homologous subtype. Labelled anti-d detected 3 ng/ml of ad antigen, but it did not bind to ay antigen. Thus, anti-d was completely monospecific. The standard FRC-RIA was only about 5 times more sensitive than the subtype RIA; 96% of HBsAg positive blood donor samples screened by FRC-RIA could by subtyped by RIA.The important feature of this method is the absorption of the antibodies in the presence of carrier protein after radioactive labelling. This has certain advantages: (1) No extra radioactive labelling is needed for subtyping, because the labelled anti-HBs of standard RIAs for HBsAg can be utilized. (2) Small amounts of labelled monospecific antibodies can be prepared at a time, which promotes economical use of reagents. (3) Only crude antigen preparation (e.g. polyethyleneglycol precipitate from plasma) is needed for the absorption of antibodies.     

Distribution of anti-HBs levels in Korean adults

Exact titration of anti-HBs with mIU/mL unit is necessary in evaluating the success of HBV vaccination or in making a decision to increase the dose of HBV vaccination. Data of distribution of anti-HBs titers can contribute to cutting of public health costs by reducing unnecessary HBV booster doses. Moreover, anti-HBc is also an important marker for differentiation of vaccination-induced anti-HBs from infection-acquired anti-HBs. However, not much study about these subjects has been done in Korea. So we evaluated anti-HBs associated with anti-HBc and vaccination history. HBsAg and anti-HBs tests were done in 1,465 cases. The positive rates of HBsAg and anti-HBs were 4.5% and 74.6%, respectively. Anti-HBs positive rate was higher in the vaccinated group than that in the non-vaccinated group. The rates of anti-HBs positive cases with lower titers (10-< 100 mIU/mL) were 31.9%, while cases with higher titers (> or = 100 mIU/mL) were 68.1%. This suggested about 70% of anti-HBs-positive Korean adults (about 53% of the general adult population) have long-lasting immunity against HBV infection and may not require booster doses of HBV vaccination for a long time. Anti-HBs titers in the vaccine-induced anti-HBs group were higher than those in the infection-acquired anti-HBs group. No statistical differences were noted between male and female or among age groups. 25.7% of the HBsAg (-)/anti-HBs (-) group showed anti-HBc positive and HBV-DNA was detected in 11.1% among HBsAg (-)/anti-HBs (-)/anti-HBcAb (+) cases. Further study about post vaccination anti-HBs titer decay in Korean should be performed to help cut vaccination costs.     

Regulation of the Immune Response to Hepatitis B Virus and Human Serum Albumin

The circulatory pool of B cells, from donors immune lo hepatitis B (HB) through natural infection, contained sensitized B cells with the capacity to secrete antibodies with specificity for human serum albumin (USA) 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-USA 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 USA in association with HBV/HBsAg particles may involve a putative risk for development of chronic HBsAg carriership.     

Chronic delta hepatitis in haemophiliacs

The seroepidemiological profile of HBV and HDV was investigated in 640 male haemophiliacs. Twenty-seven of forty-four HBsAg carriers were anti-HDV-IgG positive, 22 were also anti-HDV-IgM positive. A markedly lower prevalence of HDV infection was found in patients with anti-HBc in the absence of HBsAg and anti-HBs (6/41). Repeated detection of anti-HDV-IgM in 5/41 individuals of this group indicates that circulating HBsAg is not an absolute prerequisite for chronic HDV infection. Overall, chronically active HDV infection was detected more frequently in quiescent than in active chronic HBV infections. Anti-HDV-IgM was not detected in the absence of anti-HDV-IgG antibodies. Anti-HDV-IgG may disappear after resolution of HDV infection, as indicated by the low prevalence (1/42) in such individuals with past HBV infection as well as by loss of anti-HDV-IgG observed in two patients.     

Mutations in hepatitis B virus DNA from patients with coexisting HBsAg and anti-HBs

Background

The serological markers with coexistence of hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) of hepatitis B virus (HBV) infection were rare pattern. The virological significance, immune response and clinical outcome of these patients remain largely unknown.

Objectives

This research explores the relationship between this serological profile and HBV genome variants.

Study design

We studied 35 patients both carrying HBsAg and anti-HBs (group I), and 70 patients with HBsAg positive but anti-HBs negative (group II, served as control). The HBV genome sequences were obtained by direct sequencing of polymerase chain reaction (PCR) products.

Results

The amino acid (aa) variation within major hydrophilic region (MHR), especially in the first loop (aa124-137) of “a” determinant in group I is significantly higher than those in group II. The aa variation of cytotoxic lymphocyte (CTL) epitope in HBsAg (aa87–aa95) in group I is also significantly higher than that in group II. Interestingly, the basal core promoter (BCP) double mutations (A1762T/G1764A) in group I is significantly higher than those in group II as well.

Conclusions

In patients with HBV infection, the coexistence of HBsAg and anti-HBs is associated with an increased aa variability in several key areas of HBV genome. The molecular characteristic of HBV in HBsAg and anti-HBs positive patients is distinct and worth further studies.     

Neutralization of hepatitis B virus infectivity by a murine monoclonal antibody: an experimental study in the chimpanzee

Two study chimpanzees were inoculated intravenously with approximately 1,000 chimpanzee infectious doses of hepatitis B virus (HBV), one with subtype adr and one with subtype ayw, each previously incubated with 0.1 ml of a murine monoclonal antibody (IgG 1(K) class) directed against a single epitope on hepatitis B surface antigen common to most or all HBV. Two control chimpanzees received identical doses of HBV not incubated with the murine anti-HBs. Neither study chimpanzee developed HBV infection during 12 months of follow-up as judged by normal serum aminotransferase activity, normal liver biopsies, and negative serological tests for HBV-associated antigens and antibodies. In contrast, both control chimpanzees became infected by HBV as evidenced by elevated serum aminotransferase activity, liver biopsy changes characteristic of viral hepatitis, and the appearance of hepatitis B surface antigen (HBsAg) in their sera. Both study chimpanzees were shown to be fully susceptible to infection with these same HBV inocula when challenged 15 months after the initial inoculations at a time when passively administered anti-HBs was no longer detectable. Prior to challenge with HBV, one of the two study chimpanzees received a second injection of the same volume of the murine monoclonal anti-HBs. The survival of this anti-HBs in serum was reduced from six weeks (after the initial injection) to approximately two weeks.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.