Distribution of IgG subclasses after anti-hepatitis B virus immunization with a recombinant vaccine

Cross-Sectional Association of Urinary Bisphenol A and Vaccine-Induced Immunity against Hepatitis B Virus: Data from the 2003–2014 National Health and Nutrition Examination Survey

Hepatitis B virus (HBV) infection poses a serious health burden; bisphenol A (BPA), a commonly used plasticizer for consumer products, is a potential immune disruptor. However, epidemiologic studies revealing the association between BPA exposure and immunity are limited. This study investigates the association between environmental BPA exposure and immune response following HBV vaccination in a nationally representative sample population. Using National Health and Nutrition Examination Survey data from six cycles, we analyzed the data of 6134 participants, classified as susceptible to HBV infection (n = 3086) or as having vaccine-induced immunity (n = 3048). Associations between BPA level and HBV susceptibility were assessed using multivariable logistic regression and expressed as odds ratios (ORs) of the pooled data and data for each cycle. There was a significant association in the pooled data after adjusting for potential confounders (adjusted OR (aOR): 1.14, 95% confidence interval (CI): 1.05–1.23). However, the associations between BPA concentration and HBV susceptibility were inconsistent across the survey cycles and tended to decrease in more recent cycles. Although this study preliminarily suggests that BPA attenuates the immune response to hepatitis B vaccination, further prospective studies are warranted to elucidate the discrepancies observed.

Generation and characterization of high affinity humanized fab against hepatitis B surface antigen

5S is a mouse monoclonal IgG1 that binds to the 'a' epitope of the Hepatitis B surface antigen (HBsAg) and tested positive in an in vitro test for virus neutralization. We have earlier reported the generation of humanized single chain variable fragment (scFv) from the same. In this article we report the generation of a recombinant Fab molecule by fusing humanized variable domains of 5S with the constant domains of human IgG1. The humanized Fab expressed in E. coli and subsequently purified, retained a high binding affinity (K(D) = 3.63 nmol/L) to HBsAg and bound to the same epitope of HBsAg as the parent molecule. The humanized Fab also maintained antigen binding in the presence of various destabilizing agents like 3 M NaCl, 30% DMSO, 8 M urea, and extreme pH. This high affinity humanized Fab provides a basis for the development of therapeutic molecules that can be safely utilized for the prophylaxis and treatment for Hepatitis B infection.

Generation and characterization of a single-gene mouse-human chimeric antibody against hepatitis B surface antigen

BACKGROUND

Antibody against hepatitis B surface antigen (HBsAg) is used for passive immunotherapy in certain cases of hepatitis B infection. The authors have earlier reported a high-affinity mouse monoclonal (5S) against HBsAg. However, this mouse antibody cannot be used for therapeutic purposes because it may elicit antimouse immune responses. Chimerization by replacing mouse constant domains with human ones can reduce the immunogenicity of this antibody.

METHODS

A single-chain variable fragment (scFv), derived from the mouse monoclonal 5S, was fused with the fragment crystallisable (Fc) fragment of human IgG1. The scFv region is expected to bind to the antigen, whereas the Fc fragment can provide the effector functions required for virus neutralization. This chimeric molecule was expressed in Chinese hamster ovary (CHO) cells in serum-free medium. It was purified by affinity chromatography and characterized by in vitro binding studies.

RESULTS

Purification and characterization indicated that this chimeric scFv-Fc fusion protein is secreted as a disulfide-linked, glycosylated, homodimeric molecule. The yield of the purified chimeric antibody was approximately 4.6 mg/L. In vitro analyses confirmed that this chimeric molecule retained the high affinity and specificity of the original mouse monoclonal.

CONCLUSION

Because it is a single-gene product, this chimeric scFv-Fc has the advantage of stable expression. Being chimeric and bivalent, it is expected to be less immunogenic and therefore suitable for further in vivo studies on virus neutralization.

High affinity mouse-human chimeric Fab against hepatitis B surface antigen

AIM

Passive immunotherapy using antibody against hepatitis B surface antigen (HBsAg) has been advocated in certain cases of Hepatitis B infection. We had earlier reported on the cloning and expression of a high affinity scFv derived from a mouse monoclonal (5S) against HBsAg. However this mouse antibody cannot be used for therapeutic purposes as it may elicit anti-mouse immune responses. Chimerization by replacing mouse constant domains with human ones can reduce the immunogenicity of this antibody.

METHODS

We cloned the V(H) and V(L) genes of this mouse antibody, and fused them with CH1 domain of human IgG1 and C(L) domain of human kappa chain respectively. These chimeric genes were cloned into a phagemid vector. After initial screening using the phage display system, the chimeric Fab was expressed in soluble form in E. coli.

RESULTS

The chimeric Fab was purified from the bacterial periplasmic extract. We characterized the chimeric Fab using several in vitro techniques and it was observed that the chimeric molecule retained the high affinity and specificity of the original mouse monoclonal. This chimeric antibody fragment was further expressed in different strains of E. coli to increase the yield.

CONCLUSION

We have generated a mouse-human chimeric Fab against HBsAg without any significant loss in binding and epitope specificity. This chimeric Fab fragment can be further modified to generate a full-length chimeric antibody for therapeutic uses.

Perspectives on hepatitis B infections and the efficacy of vaccination (hepatitis B and pneumococci) in dialysis patients

Hepatitis B is a well known problem in dialysis units. We therefore examined the historical frequency of hepatitis B carriers in our unit, our vaccination program to hepatitis B virus (HBV), the response to hepatitis B vaccine, the IgG subclass response of anti-HBs and the response and IgG subclass response to pneumococcal vaccination (another vaccine) in dialysis patients. From 1970 and onwards 23 HBV carriers were found, but no new cases of hepatitis B occurred during the study period, i.e. from 1980 and onwards. Only one of the carriers was alive by the end of 2001. In four patients liver disease (in one of them liver cirrhosis) may have been a concomitant cause of death. The antibody response to hepatitis B vaccine was significantly lower in patients than in staff. In four patients a fourth injection was cancelled due to transplantation and bad health, while such data were lacking in 8 cases. In anti-HBs positive patients and controls a significant difference in the response of healthy adults was observed in anti-HBs IgG1 (p < 0.001) vs all other IgG subclasses. Dialysis patients had low levels, or negative findings, in all cases, with IgG1 as the highest proportion found (3/11 patients). An antibody response to pneumococcal vaccination was registered in 25 out of 29 dialysis patients (in all 86%). The IgG-subclass vaccination response to pneumococci in 28 dialysis patients was mainly IgG2 and IgG1 but also occurred in IgG3 and IgG4. Prevaccination antibody levels of the controls were higher in IgG1 and IgG2 (p < 0.01) (n = 21) than in dialysis patients (n = 28). Hepatitis B is nowadays a rare, but still dangerous disease in nephrology units. Dialysis patients have a reduced response to hepatitis B vaccine and vaccination schedules should be started early as some patients otherwise may not receive a fourth injection. The adequate antibody response to pneumococcal vaccination mainly due to IgG2 and IgG1 antibodies indicates that the antigen involved is important in vaccination responses in dialysis patients.

Hepatitis B vaccine in infants: a randomized controlled trial comparing gluteal versus anterolateral thigh muscle administration

A significantly diminished antibody response to hepatitis B vaccine has been demonstrated in adults when the buttock is used as the injection site. However, in Brazil, the buttock continues to be recommended as site of injection for intramuscular administration of vaccines in infants. In this age group, there are no controlled studies evaluating the immunogenicity of the hepatitis B vaccine when administered at this site. In the present study, 258 infants were randomized to receive the hepatitis B vaccine either in the buttock (n = 123) or in the anterolateral thigh muscle (n = 135). The immunization schedule consisted of three doses of hepatitis B vaccine (Engerix Bregister mark or target, 10 microg) at 2, 4 and 9 months of age. There were no significant differences in the proportion of seroconversion (99.3% x 99.2%), or in the geometric mean titer of ELISA anti-HBs (1,862.1 x 1,229.0 mIU/mL) between the two groups. This study demonstrates that a satisfactory serological response can be obtained when the hepatitis B vaccine is administered intramuscularly into the buttock.

Immunoglobulin subclasses in patients with neutralizing and nonneutralizing antibodies against IFN-beta1b

Treatment of multiple sclerosis (MS) with interferon-beta1b (IFN-beta1b) induces the production of antibodies in some patients. A proportion of these antibodies can reduce the biologic activity of IFN-beta, and they are, therefore, referred to as neutralizing antibodies (NAB). The remaining antibodies do not interfere with the biologic activity of IFN-beta and are referred to as nonneutralizing antibodies (NNAB) in this paper. Immunoglobulin (Ig) subtyping of these antibodies was carried out, and Ig subclass patterns in 20 patients with NAB were compared with those of NNAB in 39 patients. In patients with NAB, IgG2 and IgG4 were found to occur more frequently than in patients with NNAB (30% vs. 3%, p = 0.05, and 55% vs. 18%, p = 0.003, respectively) The NAB titer correlated strongly with the IgG4 titer (r = 0.53, p = 0.02). Median total IgG, IgG1, and IgG4 titers were significantly higher in NAB than in NNAB patients (respectively, 8000 vs. 3200, p = 0.01; 1600 vs. 400, p = 0.0004; 200 vs. 0, p = 0.004). It is concluded that the development of NAB is related to both the quantity and the quality of the antibodies against IFN-beta1b.