Defect in Th1-like cells of nonresponders to hepatitis B vaccine

Hepatitis B vaccine delivered by microneedle patch: Immunogenicity in mice and rhesus macaques

Vaccination against hepatitis B using a dissolving microneedle patch (dMNP) could increase access to the birth dose by reducing expertise needed for vaccine administration, refrigerated storage, and safe disposal of biohazardous sharps waste. In this study, we developed a dMNP to administer hepatitis B surface antigen (HBsAg) adjuvant-free monovalent vaccine (AFV) at doses of 5 µg, 10 µg, and 20 µg, and compared its immunogenicity to vaccination with 10 µg of standard monovalent HBsAg delivered by intramuscular (IM) injection either in an AFV format or as aluminum-adjuvanted vaccine (AAV). Vaccination was performed on a three dose schedule of 0, 3, and 9 weeks in mice and 0, 4, and 24 weeks in rhesus macaques. Vaccination by dMNP induced protective levels of anti-HBs antibody responses (≥10 mIU/ml) in mice and rhesus macaques at all three HBsAg doses studied. HBsAg delivered by dMNP induced higher anti-HBsAg antibody (anti-HBs) responses than the 10 µg IM AFV, but lower responses than 10 µg IM AAV, in mice and rhesus macaques. HBsAg-specific CD4+ and CD8+ T cell responses were detected in all vaccine groups. Furthermore, we analyzed differential gene expression profiles related to each vaccine delivery group and found that tissue stress, T cell receptor signaling, and NFκB signaling pathways were activated in all groups. These results suggest that HBsAg delivered by dMNP, IM AFV, and IM AAV have similar signaling pathways to induce innate and adaptive immune responses. We further demonstrated that dMNP was stable at room temperature (20 °C-25 °C) for 6 months, maintaining 67 ± 6 % HBsAg potency. This study provides evidence that delivery of 10 µg (birth dose) AFV by dMNP induced protective levels of antibody responses in mice and rhesus macaques. The dMNPs developed in this study could be used to improve hepatitis B birth dose vaccination coverage levels in resource limited regions to achieve and maintain hepatitis B elimination.

Hepatitis B Vaccine Non-Responders Show Higher Frequencies of CD24highCD38high Regulatory B Cells and Lower Levels of IL-10 Expression Compared to Responders

Background

The cellular mechanisms involved in the lack of protective antibody response after hepatitis B vaccination are still rather unclear. Regulatory B cells (Breg) known as modulators of B-and T-cell responses may contribute to poor vaccine responsiveness. The current study aimed to investigate the role of regulatory B cells (Breg) in hepatitis B vaccine non-responsiveness after immunization with second- or third-generation hepatitis B vaccines.

Method

We performed comparative phenotypic and frequency analysis of Breg subsets (CD24⁺CD27⁺ and CD24^highCD38^high Breg) in second-generation hepatitis B vaccine non-responders (2^nd HBvac NR, n = 11) and responders (2^nd HBvac R, n = 8) before (d0), on day 7 (d7), and 28 (d28) after booster vaccination. Cryopreserved peripheral blood mononuclear cells were stimulated ex vivo with a combination of CpG, PMA, and Ionomycin (CpG+P/I) and analyzed for numbers and IL-10 expression levels of Breg by flow cytometry-based analyses.

Results

Flow cytometry-based analyses revealed elevated frequencies of CD24⁺CD27⁺ Breg at all time points and significantly higher frequencies of CD24^highCD38^high Breg on d0 (p = 0.004) and 28 (p = 0.012) in 2^nd HBvac NR compared to 2^nd HBvac R. In parallel, we observed significantly lower levels of CpG+P/I-induced IL-10 expression levels of CD24⁺CD27⁺ and CD24^highCD38^high Breg (d0: p < 0.0001; d7: p = 0.0004; d28: p = 0.0003 and d0: p = 0.016; d7: p = 0.016, respectively) in 2^nd HBvac NR compared to 2^nd HBvac R before and after booster immunization. Frequencies of CD24⁺CD27⁺ and CD24^highCD38^high Breg significantly decreased after third-generation hepatitis B booster vaccination (d7: p = 0.014; d28: p = 0.032 and d7: p = 0.045, respectively), whereas IL-10 expression levels of both Breg subsets remained stable.

Conclusion

Here we report significantly higher frequencies of CD24^highCD38^high Breg in parallel with significantly lower IL-10 expression levels of CD24⁺CD27⁺ and CD24^highCD38^high Breg in 2^nd HBvac NR compared to 2^nd HBvac R. Anti-HBs seroconversion accompanied by a decrease of Breg numbers after booster immunization with a third-generation hepatitis B vaccine could indicate a positive effect of third-generation hepatitis B vaccines on Breg-mediated immunomodulation in hepatitis B vaccine non-responders.

Molecular Evaluation of Oral Immunogenicity of Hepatitis B Antigen Delivered by Hydrogel Microparticles

The development of oral vaccine formulation is crucial to facilitate an effective mass immunization program for various vaccine-preventable diseases. In this work, the efficacy of hepatitis B antigen delivered by bacterial nanocellulose/poly(acrylic acid) composite hydrogel microparticles (MPs) as oral vaccine carriers was assessed to induce both local and systemic immunity. Optimal pH-responsive swelling, mucoadhesiveness, protein drug loading, and drug permeability were characterized by MPs formulated with minimal irradiation doses and acrylic acid concentration. The composite hydrogel materials of bacterial nanocellulose and poly(acrylic acid) showed significantly greater antigen release in simulated intestinal fluid while ensuring the integrity of antigen. In in vivo study, mice orally vaccinated with antigen-loaded hydrogel MPs showed enhanced vaccine immunogenicity with significantly higher secretion of mucosal immunoglobulin A, compared to intramuscular vaccinated control. The splenocytes from the same group demonstrated lymphoproliferation and significant increased secretion of interleukin-2 cytokines upon stimulation with hepatitis B antigen. Expression of CD69 in CD4⁺ T lymphocytes and CD19⁺ B lymphocytes in splenocytes from mice orally vaccinated with antigen-loaded hydrogel MPs was comparable to that of the intramuscular vaccinated control, indicating early activation of lymphocytes elicited by our oral vaccine formulation in just two doses. These results demonstrated the potential of antigen-loaded hydrogel MPs as an oral vaccination method for hepatitis B.

Expression profiles of transcription factors for special CD4+ T-cell subsets in peripheral blood mononuclear cells from patients with hepatitis B virus infection

This study is to characterize the transcription factor expression profiles for the peripheral CD4 T-cell subsets, and analyze its associations with the clinical measures of the hepatitis B virus (HBV) infection.Totally 275 subjects were included. The expression levels of transcription factors (T-bet, GATA-3, Foxp3, RORγt, and Bcl-6) in the peripheral blood mononuclear cells (PBMCs) were determined by the real-time fluorimetry quantitative PCR (FQ-PCR).Lowest expression levels of all these transcription factors were observed for the HBsAb(-) group, which were higher in the HBsAb(+) and RHB groups. The T-bet/GATA-3 ratios in the CHB and RHB groups were significantly lower than the HBsAb(-) group, whereas the RORγt/Foxp3 ratios in the AHB and RHB groups were significantly higher than the CHB and HBsAb(+) groups. Furthermore, the RORγt mRNA expression levels were significantly different among groups with different disease severities or with different alanine aminotransferase (ALT) levels. The asymptomatic carrier (AsC) group and the group with ALT ≤ 40 had the highest express level. The mRNA expression levels of T-bet, GATA-3, Foxp3, and RORγt varied along with the aspartate aminotransferase (AST) levels, with AST ≤ 40 having the highest expression levels. In addition, significant differences were observed in the transcription factor expression levels between the group with the serum HBV DNA load of (1.000-9.999) × 10 copies/mL and other groups.Expression profile of critical transcription factors for peripheral CD4 T-cell subsets may indicate clinical outcomes of HBV infection.

Humoral and cell-mediated immune responses after a booster dose of HBV vaccine in HIV-infected children, adolescents and young adults

OBJECTIVE

HBV vaccine induces protective antibodies only in 23-56% of HIV-infected children. The aim of our study is to evaluate the immunologic effects of a booster dose of HBV vaccine in HIV-infected youth.

DESIGN

53 young HIV-infected patients in whom HBV vaccination did not elicit protective Ab titers were enrolled. All patients were on ART with optimal immunological and viral response.

METHOD

All patients received a booster dose of HBV vaccine (HBVAXPRO 10 μg i.m.). HBV-specific Ab titer, viral load and CD4+ T cells were measured at baseline (T0), T1, T6 and T12 months. In a subgroup of 16 patients HBV-specific cell mediated immune responses were evaluated at baseline, at T1 and T6.

RESULTS

The booster dose induced seroconversion in 51% of patients at T1, 57% at T6, and49% at T12; seroconversion rate was significantly correlated with CD4+T cells at T0 and to the CD4 nadir. The booster dose induced HBV-specific cell mediated immunity at T6 mainly in Responders (Rs): Effector Memory CD8+T cells, HBV-specific TNFα-, IFNγ-, granzyme secreting CD8+ T cells and IL2-secreting CD4+ T cells were significantly increased in Rs compared to T0. In Non Responders (NRs), HBV-specific IL2-secreting CD4+ T cells, Central and Effector Memory CD8+ T cells were the only parameters modified at T6.

CONCLUSIONS

Seroconversion induced by a booster dose of vaccine correlates with the development of T cell immunological memory in HIV-infected patients who did not respond to the standard immunization. Alternate immunization schedules need to be considered in NRs.

A Prospective Study of Humoral and Cellular Immune Responses to Hepatitis B Vaccination in Habitual Marijuana Smokers

Exposure to Δ⁹-tetrahydrocannabinol (THC) in vitro and in animal models can significantly impair the differentiation, activation and function of dendritic cells, T cells and B cells. However, studies directly assessing the impact of marijuana smoking on human immunity are lacking. A prospective study of immune responses to a standard hepatitis B vaccination was therefore carried out in a matched cohort of 9 marijuana smokers (MS) and 9 nonsmokers (NS). In addition to their regular marijuana use, MS smoked four marijuana cigarettes in a monitored setting on the day of each vaccination. Blood samples were collected over time to assess the development of hepatitis B-specific immunity. The majority of subjects from both the NS (8) and MS (6) groups developed positive hepatitis B surface antibody titers (>10 IU/L) and of these 6 NS and 5 MS were classified as high antibody (good) responders (>100 IU/L). The development of a good response correlated with the presence of hepatitis B-specific T cell proliferation and cytokine production, resulting in a clear distinction regarding the immune status of good responders versus non-responders. However, even though there were slighter more non-responders in the MS cohort, there were no significant differences between MS and NS with respect to peripheral blood cell phenotypes or vaccination-related changes in hepatitis B responses. While a larger cohort may be required to rule out a small suppressive effect, our findings do not suggest that habitual marijuana smoking exerts a major impact on the development of systemic immunity to hepatitis B vaccination.

Identification of occult hepatitis B virus (HBV) infection and viral antigens in healthcare workers who presented low to moderate levels of anti-HBs after HBV vaccination

BACKGROUND

Worldwide, healthcare workers (HCWs) show different levels of response to hepatitis B virus (HBV) vaccine. One of the factors associated with vaccine unresponsiveness may be the existence of current or past HBV infection. Regardless of the presence of HBsAg (overt infection), occult HBV infection (OBI, defined as presence of HBV DNA in the absence of HBsAg) might also account for some non- or hypo-response cases.

METHODS

Sera from 120 HBsAg-negative HCWs with low and moderate levels of anti-HBs, <10 IU/mL (group I) and <100 IU/mL (group II) respectively, were selected and were examined for OBI by sensitive real-time PCR regardless of HBV serological profiles. Direct sequencing on surface genes was carried out in OBI-positive cases.

RESULTS

Four (3.3%) were positive for OBI. All were negative for anti-HBc. Two of the positive cases had moderate levels of anti-HBs (>10 to <100 IU/mL). No significant differences were found between the two groups in terms of risk factors or serological data. No mutations were found in surface proteins of OBI cases.

CONCLUSION

OBI in these subjects might be due to other factors rather than presence of "a" determinant mutations. Healthcare workers with inadequate to moderate levels of anti-HBs (<100 IU/mL) following vaccination, regardless of their serological profile for HBV, should be tested for the presence of HBV DNA by sensitive molecular tests. Anti-HBc is not a reliable marker for suspicion of OBI, especially in high-risk group individuals.

Synthetic innate defense regulator peptide combination using CpG ODN as a novel adjuvant induces long‑lasting and balanced immune responses

Vaccines are critical tools for the prevention and treatment of several diseases. Adjuvants have been traditionally used to enhance immunity to vaccines and experimental antigens. In the present study, the adjuvant combination of CpG oligodeoxynucleotides (CpG ODN) and the innate defense regulator (IDR) peptide, IDR‑HH2, was evaluated for its ability to enhance and modulate the immune response when formulated with alum and the recombinant hepatitis B surface antigen (HBsAg). The CpG‑HH2 complex enhanced the secretions of tumor necrosis factor‑α, monocyte chemotactic protein 1 and interferon‑γ by human peripheral blood mononuclear cells and promoted murine bone marrow dentritic cell maturation. In addition, the present study demonstrated that IDR‑HH2 was chemotactic for human neutrophils, THP‑1 cells and RAW264.7 cells at concentrations between 2.5 and 40 µg/ml. The present study also observed that significantly higher anti‑HBs antibody titers, which were sustained at high levels for as long as 35 weeks following the boost immunization, were induced by the combination adjuvant, even when co‑administered with a commercial hepatitis B vaccine at a low antigen dose (0.1 µg HBsAg). Notably, the level of IgG2a was almost equal to the level of IgG1, indicating that a balanced T helper (Th)1/Th2 immune response was elicited by the novel vaccine, which was consistent with the ELISpot results. These data suggest that the CpG‑HH2 complex may be a potential effective adjuvant, which facilitates a reduction in the dose of antigen and induces long‑lasting, balanced immune responses.

Prevention of hepatitis B virus infection: from the past to the future

About 3-5 % of the world's population is chronically infected by hepatitis B virus (HBV) and is at risk of developing liver cirrhosis or hepatocellular carcinoma. The risk of dying prematurely because of chronic HBV infection is higher in younger people. The current strategies to prevent HBV infection involve immunization (active and/or passive) and antiviral chemoprophylaxis. The vaccines available for active immunization, containing hepatitis B surface antigen, are safe and confer long-term immunity in most healthy subjects. Since the vaccination is unsatisfactory in some patients, e.g., those with chronic kidney disease, human immunodeficiency virus infection, type I diabetes mellitus, and celiac disease, new strategies of vaccination are required. The neonatal, infant, and adolescent routine program vaccination in about 180 countries has greatly decreased the disease burden. Passive immunization with specific HBV immunoglobulins is recommended after single acute exposure, in infants born to infected mothers, and in HBV-infected patients undergoing liver transplantation combined with nucleoside/nucleotide analogues (chemoprophylaxis). Chemoprophylaxis is also indicated in HBV carrier candidates for immunosuppressive treatment and in patients with occult B infection undergoing immunosuppressive therapy or hematopoietic stem cell transplantation. Since HBV is not eradicable by an immune response or by antiviral drugs developed so far, the only preventive strategy remains global neonatal vaccination in all countries, firstly in HBV-endemic countries.

IFNG and IFNGR1 gene polymorphisms in children with nonresponse to the hepatitis B vaccine

ABSTRACT: 

Aim: We investigated the +874 T/A polymorphism in the first intron of the IFNG gene and intronic (CA)n polymorphic microsatellite marker of the IFNGR 1 gene in child nonresponders to hepatitis B vaccination. Materials & methods: A total of 100 children who had anti-HBs antibody levels <10 mIU/ml after vaccination against hepatitis B were included as a nonresponder group and 100 children who had anti-HBs antibody levels >10 mIU/ml after vaccination against hepatitis B were included as a responder group. Results: The frequency of the TT genotype of the IFNG (+874 T/A) gene polymorphism was higher in nonresponders (p = 0.003). The frequencies of alleles 170 and 182 for (CA)n alleles for the intronic (CA)n microsatellite of IFNGR1 were significantly higher in nonresponders (for each, p < 0.05). Conclusion: The TT genotype of the IFNG (+874 T/A) gene, and alleles 170 and 182 for (CA)n alleles for the intronic (CA)n microsatellite of the IFNGR1 gene, may be associated with nonresponse to hepatitis B vaccination.

Association of the interleukin-12 polymorphic variants with the development of antibodies to surface antigen of hepatitis B virus in hemodialysis patients in response to vaccination or infection

Cytokines, involved in the T-helper 1 system, play a role in the regulation of hepatitis B virus (HBV) clearance and the immune response to HBV antigens during natural infection or planned vaccination. Our aim was to examine whether the polymorphic variants of IL-12 are equally associated with development of antibodies to HBV surface antigen (anti-HBs) in hemodialysis (HD) patients in the case of HBV vaccination or HBV infection. The IL-12A rs568408 and IL-12B rs3212227 polymorphisms were analyzed in relation to anti-HBs development in 602 HD patients with negative antibodies to HBV core antigen (anti-HBc) who were hepatitis B vaccinated (group I) as well as in 237 anti-HBc positive HD patients who were infected with HBV in the past (group II). In group I, 199 patients did not develop an anti-HBs titre >10 IU/L (subgroup Ia), whereas in group II, 55 patients did not develop an anti-HBs titre >10 IU/L (subgroup IIa). Patients of groups I and II that developed an anti-HBs >10 IU/L were included into subgroups Ib and IIb, respectively. In hepatitis B vaccinated HD patients, development of a protective anti-HBs titre was positively associated with vintage of renal replacement therapy (RRT), chronic glomerulonephritis as a cause of RRT, and GA rs 568408 IL-12A (OR 1.6, 95 % CI 1.0-2.5, P = 0.035), but a frequency distribution of this genotype between responders and non-responders was not significant when the Bonferroni correction was applied. In HBV infected HD patients, anti-HBs development was positively associated with AC rs3212227 IL-12B (OR 8.0, 95 % CI 2.6-24.9, P < 0.001), whereas HBsAg positivity, AA rs3212227 IL-12B (OR 0.3, 95 % CI 0.1-0.7, P = 0.007), and CC rs3212227 IL-12B (OR 0.1, 95 % CI 0.03-0.6, P = 0.011) were negative predictors of positive anti-HBs phenotype. When the Bonferroni correction was applied, if appropriate, these associations remained significant. In HD patients, the studied IL-12 polymorphic variants seem to be associated with the anti-HBs phenotype (a) with borderline significance for IL-12A in hepatitis B vaccinated patients, and (b) significantly for IL-12B in patients who underwent natural HBV infection.

Effect of glycyrrhizin on mRNA expression of cytokines in PBMCs from non-responders to hepatitis B vaccine

AIM: To investigate the effect of glycyrrhizin (GL) on the mRNA expression of cytokines in peripheral blood mononuclear cells (PBMCs) from non-responders to hepatitis B vaccine and to explore the mechanism by which GL regulates immune function.

METHODS: PBMCs were isolated from non-responders to hepatitis B vaccine and incubated with GL and (or) HBsAg. The abilities of GL and (or) HBsAg to stimulate the proliferation of PBMCs were evaluated by CCK-8 assay. The mRNA expression levels of IFN-γ, IL-4, and IL-10 were determined by real-time PCR.

RESULTS: GL enhanced the proliferation of PBMCs from non-responders to hepatitis B vaccine and made it comparable to that of PBMCs from responders (F = 3.104, P = 0.138). The mRNA expression levels of IFN-γ and IL-10 in PBMCs from non-responders that were incubated with HBsAg and GL were significantly higher than those incubated with HBsAg alone (q = 34.93, 26.18, both P < 0.05), and tend to reach the levels in PBMCs from responders. The mRNA expression levels of IFN-γ and IL-10 in PBMCs from non-responders that were incubated with GL were higher than those incubated with HBsAg (q = 10.18, 9.19, both P < 0.05), but lower than those incubated with HBsAg and GL (q = 24.75, 16.98, both P < 0.05). The mRNA expression levels of IL-4 had no obvious difference among the three groups (P = 0.304).

CONCLUSION: GL can regulate the immune status of non-responders to hepatitis B vaccine and create an environment conducive to the generation of protective antibodies.

Recombinant Semliki Forest virus vectors encoding hepatitis B virus small surface and pre-S1 antigens induce broadly reactive neutralizing antibodies

Most hepatitis B virus (HBV) vaccines consist of viral small surface (S) protein subtype adw2 expressed in yeast cells. In spite of good efficacy, HBV-genotype and subtype differences, escape mutants and insufficient Th1 activation remain potential problems. To address these problems, we generated recombinant Semliki Forest virus (rSFV) vectors encoding S protein, subtype adw2 or ayw2, or a fragment of the large surface protein, amino acids 1-48 of the pre-S1 domain, fused to S (pre-S1.1-48/S). The antigen loop in S protein and the selected pre-S1 sequences are known targets of neutralizing antibodies. BALB/c mice were immunized intravenously with 10(7) rSFV particles and 10(8) rSFV particles 3 weeks later. Antibodies induced by rSFV encoding S proteins reacted preferentially with subtype determinants of yeast-derived S antigen but equally well with patient-derived S antigen. Immunization with rSFV encoding pre-S1.1-48/S resulted in formation of pre-S1- and S-specific immunoglobulin G (IgG), while immunization with the isogenic mutant without S start codon induced pre-S1 antibodies only. Neutralizing antibodies were determined by mixing with plasma-derived HBV/ayw2 and subsequent inoculation of susceptible primary hepatocyte cultures from Tupaia belangeri. S/adw2 antisera neutralized HBV/ayw2 as effectively as antisera raised with S/ayw2. The pre-S1 antibodies also completely neutralized HBV infectivity. The IgG1/IgG2a ratios ranged from 0.28 to 0.88 in the four immunized groups and were lowest for the pre-S1.1-48/S vector, indicating the strongest Th1 response. This vector type may induce subtype-independent and S-escape-resistant neutralizing antibodies against HBV.

Association between polymorphisms of the cytokine and cytokine receptor genes and immune response to hepatitis B vaccination in a Chinese Han population

The immune response to hepatitis B vaccination varies among individuals. It has been reported that polymorphisms in cytokine and cytokine receptor genes are associated with these individual differences. The aim of the current study was to investigate the association between polymorphisms of the Th1/Th2 cytokine and cytokine receptor genes and the response to hepatitis B vaccination in a Chinese Han population. A total of 10 single nucleotide polymorphisms distributed in 6 genes (TNFRSF1A, IL12A, IL12B, IFNG, IL4, and IL10) were genotyped in 214 high-responders [hepatitis B surface antibody (anti-HBs) ≥1,000 mIU/ml] and 107 low-responders (anti-HBs: 10-99 mIU/ml). The minor CTCTAA allele of rs17860508 in the IL12B gene was associated with a low response to hepatitis B vaccination (P = 0.039, odds ratio = 1.41, 95% confidence interval = 1.00-1.99). In addition, a significant gene-gene interaction was found: the frequency of the combined genotypes IL12A rs2243115 TT and IL12B rs17860508 CTCTAA/CTCTAA was significantly higher in the low-response group than in the high-response group (P = 0.008, odds ratio = 2.19, 95% confidence interval = 1.23-3.93). These findings suggest that polymorphisms in the IL12A and IL12B genes might play an important role jointly in determining the response to hepatitis B vaccination.

Long-term antibody persistence and immune memory to hepatitis B virus in adult celiac patients vaccinated as adolescents

Aim of this study was to investigate the anti-HBs antibody persistence and immune memory to hepatitis B virus in adult celiacs vaccinated as adolescents and the effect of a booster administration in non-protected individuals. Eleven years after primary vaccination, the proportion of vaccinees with titres ≥ 10 mIU/ml and antibody geometric mean concentrations (GMCs) were lower among celiac patients than among controls (68.6% vs 91.7%, p<0.01; GMCs 29.38 mIU/ml vs 250.6 mIU/ml, p<0.001). Participants with anti-HBs below 10 mIU/ml received a booster dose and were retested 2 weeks later to assess the anamnestic response. Post-booster anti-HBs levels were still <10 mIU/ml in 71.4% celiacs and 25% controls (p<0.01). Our findings indicate that the prevalence of seroprotective levels of anti-HBs detected eleven years after primary immunization as well as the frequency of response to a booster dose of vaccine are lower in celiac patients compared to healthy controls.

Toll-like receptors and cytokines/cytokine receptors polymorphisms associate with non-response to hepatitis B vaccine

It is well documented that 5-10% hepatitis B adult vaccinees are non- and hypo-responders and probably are not adequately protected against hepatitis B virus (HBV) infection. The sequence variations of genes involved in processes such as pathogen recognition, antigen processing and presentation, and differentiation/maturation of lymphocytes may affect the duration and intensity of protective humoral immune response to the hepatitis B vaccine. In this study, frequencies of 53 known SNPs within 21 candidate genes were analyzed among 46 responders and 24 non-responders. Four SNPs (rs2243248, rs1805015, rs1295686 and rs3804100) in IL-4, IL-4RA, IL-13 and TLR2 genes were found significantly associated with the vaccinees' status of serum anti-HBV response triggered by the vaccine (P<0.05). Two SNPs (rs1295686 and rs1805015) also showed significant association with the vaccine-induced immune response when analyzed together with risk factors such as age and gender, by multivariable logistic regression analysis (P<0.05). Further, haplotype analysis showed that the AG haplotype defined by SNPs rs1143633 (IL-1B; intron) and rs1143627 (IL-1B; intron) was present more frequently in non-responders than in responders (P=0.035). Thus, specific SNPs in genes of cytokines/cytokine receptors and TLR2 were associated with status of the hepatitis B vaccine-induced protective humoral immune response.

Blockage of Notch1 signaling modulates the T-helper (Th)1/Th2 cell balance in chronic hepatitis B patients

AIM

Chronic hepatitis B virus (HBV) infection is thought to involve the imbalance of T-helper (Th)1/Th2 cells. Many procedures found Notch signaling involved the proliferation and differentiation of T lymphocytes during development and peripheral functions. The aim of this study was to discover the effect of blockage of Notch1 signaling to Th cells and the mechanisms involved in chronic hepatitis B patients.

METHODS

CD4(+) T cells from hepatitis B patients and healthy volunteers were isolated, and Notch1 expression of CD4(+) T cells was determined by reverse transcription polymerase chain reaction (RT-PCR). Blockage of Notch1 signaling of peripheral blood mononuclear cells (PBMC) from chronic hepatitis B patients, Th1- and Th2-type cytokines were assayed by enzyme-linked immunosorbent assay and levels of T-bet, GATA-3 mRNA were measured by RT-PCR.

RESULTS

Notch1 expression of CD4(+) T cells from chronic hepatitis B patients was upregulated, on the contrary to that from acute hepatitis B patients and healthy volunteers. Blockage of Notch1 signaling can strongly inhibit the production of Th2-type cytokines and the expression of GATA-3; the production of Th1-type cytokines and the expression of T-bet, however, were enhanced.

CONCLUSION

Blockage of Notch1 signaling could regulate the immune balance of Th1/Th2 in chronic hepatitis B patients, which may be mediated partly by regulating transcription factors T-bet and GATA-3.

Association of cytokine genetic polymorphisms with the humoral immune response to recombinant vaccine against HBV in infants

The prevention of hepatitis B by vaccination is one the most efficient tools to avoid the transmission of the virus, although a considerable variability to the anti-HBsAg antibody response has been described. Recently, polymorphisms of cytokine regulating genes have been described which seem to influence the immune response to various antigens. This article's objective was to evaluate the influence of cytokine genetic polymorphisms onto the humoral immune response to hepatitis B vaccine in infants. Vaccinated children were classified according to the level of anti-HBsAg antibody titles. The genotyping for TNF (-308), TGFB1 (+869, +915), IL-10 (-1082, -819, -592), IL-6 (-174), and IFNG (+874) was accomplished by the PCR-SSP technique. The TNF (-308) allele A presented a lower but not statistically significant frequency at 5% level in high responder patients (3.7% vs. 12.3%, P = 0.0919). The same was seen for the TNF (-308) genotype GA (7.4% vs. 24.5%, P = 0.0757). Further studies in other populations and evaluation of a greater number of individuals may contribute for a better understanding of the cytokine gene polymorphism influence in general and TNF polymorphism more specifically in the humoral immune response to the HBsAg vaccination in newborn children.

Relationship between T-lymphocyte cytokine levels and sero-response to hepatitis B vaccines

AIM: To investigate the cellular defects by analyzing the (Th1/Th2) cytokine levels in vaccine responders and non-responders.

METHODS: Peripheral blood mononuclear cell (PBMC) from responders and non-responders were stimulated with or with out recombinant HBsAg or PHA. Broad spectrum of cytokines viz (Th1) IFN-γ, IL-2, TNF-α, IL-12 and (Th2) IL-10, IL-4 were measured after in vitro stimulation with recombinant HBsAg and were compared with respective antibody titers.

RESULTS: A significant decrease (P = 0.001) in Th1 and Th2 cytokines namely, IL-2, INF-γ, TNF-α and IL-10 in non-responders was observed. The level of IL-4 was not significant between the three groups. Furthermore, despite a strong Th1 and Th2 cytokine response, the level of IL-12 was elevated in high-responders compared to other groups (P = 0.001) and demonstrated a positive correlation with anti-HBs titers and Th1 cytokine response.

CONCLUSION: Our findings suggest that unresponsiveness to recombinant hepatitis B vaccines (rHB) is multifactorial, including specific failure of antigen presentation or the lack of both T helper Th1 and Th2 response.

Gluten intake interferes with the humoral immune response to recombinant hepatitis B vaccine in patients with celiac disease

OBJECTIVE

Patients with celiac disease, who often carry human leukocyte antigen-DR3;DQ2, are prone to inadequate response to hepatitis B immunization. We evaluated vaccine response in relation to disease activity and whether previous treatment with a gluten-free diet influences the achievement of protective antibody titers.

PATIENTS AND METHODS

We studied 128 children and adolescents with celiac disease and 113 age-matched control subjects. Twenty-two patients with celiac disease were prospectively immunized after diagnosis during dietary treatment (group 1). A total of 106 (group 2) and the control subjects received vaccination by mass immunization in schools at 14 years of age regardless of diet status and when celiac disease was still undiagnosed in 27 of these children. Diet compliance and celiac disease activity were monitored by measurement of antibodies against transglutaminase and endomysium. Vaccine response was determined by measuring antihepatitis B antibodies from serum.

RESULTS

The seroconversion after hepatitis B vaccination was 95.5% in group 1. All of these patients carried human leukocyte antigen DQ2. The response rate in group 2 was 50.9% and correlated with gluten intake (untreated patients: 25.9%, non-strict diet: 44.4%, strict diet: 61.4%). Treated and compliant patients did not significantly differ from control subjects (75.2%). Thirty-seven antihepatitis B-negative patients with celiac disease received a booster during a controlled gluten-free diet, and 36 (97.3%) seroconverted, irrespective of the presence of human leukocyte antigen DQ2.

CONCLUSIONS

Nonresponse to recombinant hepatitis B surface antigen may be a sign of undiagnosed celiac disease. However, there is a good vaccine response in adequately treated patients. Human leukocyte antigen DQ alleles do not seem to have a primary role. Revaccination is recommended during a controlled gluten-free diet.

T cell responses to hepatitis B surface antigen are detectable in non-vaccinated individuals

AIM: To evaluate, whether humoral hepatitis-B-vaccine non-responders also fail to mount a T cell response and to compare these results to normal vaccines.

METHODS: Fourty-seven health care employees were enrolled in this study including all available non-responders (n = 13) with an anti-HBsAg titer < 10 kU/L and all available low-responders (n = 12) with an anti-HBsAg titer < 100 kU/L. Also, 12 consecutive anti-HBsAg negative pre-vaccination subjects were enrolled as well as 10 subjects (+7 from the vaccinated group) with titers > 1000 kU/L as controls. PBMC from all subjects were analyzed by IFN-γ and IL-4 ELISPOT assays for the presence of hepatitis B surface antigen (HBsAg) reactive T cells.

RESULTS: Non-responders and low-responders had no or only very limited T cell responses, respectively. Individuals responding to vaccination with the induction of a high anti-HBsAg titer showed a strong T cell response after the third vaccination. Surprisingly, these individuals showed response even before the first vaccination. T cell response to control antigens and mitogens was similar in all groups.

CONCLUSION: Our data suggest that there is no general immune deficiency in non-/low-responders. Thus, we hypothesize that the induction of anti-HBsAg responses by vaccination is significantly dependent on the pre-existing T cell repertoire against the specific antigen rather than the presence of a general T cell defect.

Hepatitis A and B immunizations of individuals infected with human immunodeficiency virus

All persons at risk for infection with human immunodeficiency virus (HIV) types 1 and 2, including men who have sex with men, those with multiple heterosexual contacts, abusers of illegal injection drugs, and persons frequently exposed to blood and blood products, are also at high risk for hepatitis A virus (HAV) and acute and chronic hepatitis B virus (HBV) infections. HIV can prolong the duration and increase the level of HAV viremia and augment HAV-related liver abnormalities. HIV also magnifies HBV viremia and the risk of HBV reactivation, chronic active HBV infection, cirrhosis, and death. Because of these concerns, hepatitis A vaccination is recommended for all HIV-positive/HAV seronegative persons, with 2 standard doses given 6 to 12 months apart. Immune response to hepatitis A vaccines is excellent, even in moderately immune-suppressed individuals. Hepatitis B vaccination is also recommended for all HIV-positive persons lacking prior immunity. However, immune reactivity to hepatitis B vaccines is frequently suboptimal in terms of patients' rate of response, antibody titer, and durability. Relatively high CD4+ T-cell counts (> or =500/mm3) and low levels of HIV viremia (<1,000 RNA genome copies/mL plasma) are necessary to ensure adequate hepatitis B vaccine response. Higher hepatitis B vaccine doses, prolongation of the vaccination schedule, or both, as prescribed for many patients with non-HIV-related immune deficiencies, may be considered initially. Revaccination should be instituted if postvaccination titers of antibodies to hepatitis B surface antigen are <10 mIU/mL (<10 IU/L). Nonresponders may also react to a subsequent vaccine course if CD4+ T-cell counts rise to 500/mm3 following institution of highly active antiretroviral therapy; vaccine adjuvant trials are under way. Universal, age-based immunization of all young and middle-aged adults appears to be the most comprehensive way of protecting all populations who are at high risk.

Profiles of NK, NKT cell activation and cytokine production following vaccination against hepatitis B

Human natural killer (NK) cells (CD56+ CD3-) represent crucial components of the innate immune system especially against viral infections and because their activation can modulate the outcome of the adaptive immune response. NKT cells (CD56+CD3+), a lymphocyte T population characterized by expression of surface markers of NK cells, are known to be abundant in the liver and their activation could be associated with hepatic injury. Using three-color flow cytometry to measure surface receptors and intracellular cytokines, we have explored early activation signals and cytokine production in NK and NKT cells within a group of hepatitis B vaccinated and non-vaccinated individuals. A specific increase of the CD56bright cell population, the activation receptor CD69 and IFN-gamma, was observed in NK cells following incubation with recombinant HBsAg in responders to vaccination. Comparable results were observed in NKT cells showing an increment of CD69, CD25, IL-2 and IFN-gamma expression in responder subjects. These parameters were statistically diminished in non-responder individuals (p<0.05) in both groups of cells. These results demonstrate a diminished activation of these cells in non-responders to the vaccine, suggesting that NK and NKT cells play an important role in the immune response following hepatitis B vaccination.

The role of particle-mediated DNA vaccines in biodefense preparedness

Particle-mediated epidermal delivery (PMED) of DNA vaccines is based on the acceleration of DNA-coated gold directly into the cytoplasm and nuclei of living cells of the epidermis, facilitating DNA delivery and gene expression. Professional antigen-presenting cells and keratinocytes in the skin are both targeted, resulting in antigen presentation via direct transfection and cross-priming mechanisms. Only a small number of cells need to be transfected to elicit humoral, cellular and memory responses, requiring only a low DNA dose. In recent years, data have accumulated on the utility of PMED for delivery of DNA vaccines against a number of viral pathogens, including filoviruses, flaviviruses, poxviruses, togaviruses and bunyaviruses. PMED DNA immunization of rodents and nonhuman primates results in the generation of neutralizing antibody, cellular immunity, and protective efficacy against a broad range of viruses of public health concern.

Most humoral non-responders to hepatitis B vaccines develop HBV-specific cellular immune responses

About 10% of health care professionals vaccinated against hepatitis B virus (HBV) fail to develop protective antibodies. We tested the capacity of peripheral blood lymphocytes from 121 health care professionals, including 76 non-responders, to proliferate to four HBV vaccines, examined the proliferating cells' subset, production of IFN-gamma, IL-4 and IL-10, and for 22 subjects, the cytokine production genotype. Specific proliferative responses to at least one HBV antigen were noted in 75% humoral non-responders. These cells differed from the CD4+ strongly proliferating cells of responders. Non-responders frequently displayed a genotype of high TGF-beta and intermediate IL-10 secretion. Most humoral non-responders to HBV thus develop specific cellular immune responses, eventually liable to protect them against viral infection.

The nonresponse to hepatitis B vaccination is associated with impaired lymphocyte activation

Nonresponsiveness against hepatitis B vaccination has been described in 4-10% of immunized subjects. We have explored the specific cell response to hepatitis B surface antigen by analyzing: PBMC proliferation, cytokine production (Th1, Th2 profiles, and TGF-beta), and activation molecules on Th cells. A poor proliferative response was demonstrated in nonresponders (P < 0.05). T cells from responders produced all tested cytokines (P < 0.01), in contrast with nonresponders subjects (P < 0.05). Expression of CD69 and CD25 was diminished in T cells from nonresponders (P < 0.01). A reduced expression of CD40L was also detected in T cells from nonresponders (P < 0.01). An elevated correlation coefficient was observed between CD40L on CD4+ cells and antibody production. These results suggest an overall inability of T cells to be activated which could be consistent with potential differences in antigen presentation. In conclusion, our results suggest that an altered Th response may be a consequence of inappropriate early activation events.

Anti-HBs cellular immune response in kidney recipients before and 4 months after transplantation

Patients with renal failure represent a population at risk for hepatitis B, since only 50 to 60% of them develop protective humoral responses after vaccination. As this could be due to an altered regulation of cellular immune responses, the objectives of the present study were to evaluate the proliferative abilities of lymphocytes from patients with chronic renal failure after stimulation in vitro with a mitogen (pokeweed mitogen [PWM]) or HBsAg. In order to differentiate between the immunodeficiency associated with renal failure and that due to immunosuppression posttransplantation, the same subjects were tested before and 4 months after kidney transplantation. The lymphoproliferation assay used was performed by flow cytometry, which is based on sequential analysis of the cell cycle and which allows analysis of cytokine production. Serologically, the group of 36 patients tested comprised 22% nonresponders, 30% poor responders, and 48% responders. Lymphocyte growth was observed for all patients after stimulation with PWM, indicating that these cells had the capacity to proliferate in vitro. The level of lymphoproliferation in response to PWM was significantly reduced after transplantation, yet both before and after transplantation, all serologic nonresponders developed cellular responses to at least two vaccines. No correlation between humoral and cellular responses was shown. Proliferating cells were lymphocytes, which mostly secreted interleukin 4 (IL-4) and IL-10 for the three serologic groups. This study suggests that even when repeated vaccination fails to induce significant antibody levels in patients with renal failure, specific HBs cellular responses develop, and these may prove to be efficient in protecting these patients against hepatitis B.

Particle-mediated DNA vaccine delivery to the skin

Particle-mediated DNA vaccines employ a physical, intracellular delivery device to achieve the deposition of plasmid DNA-based expression vectors directly into the interior of cells of the skin. The resultant bolus of transient antigen expression in keratinocytes and trafficking dendritic cells results in the induction of humoral and cellular immune responses in various animal models and humans, mimicking characteristics of live or live-vectored vaccines. Ultimately, DNA vaccine success in the clinic will depend on both the successful intracellular delivery of a plasmid vector and an immunostimulator or adjuvant to maximise humoral and cellular immune responses to the encoded antigen(s). To this end, recent DNA vaccine clinical trials are confirming the importance of an intracellular delivery system, while preclinical studies in animal models are demonstrating the feasibility of augmenting responses through the use of DNA-encoded immunostimulators. Particle-mediated DNA vaccines represent a promising tool for developing candidate vaccines against some of the more difficult infectious, parasitic and oncologic disease targets.

IgA deficiency: clinical correlates and responses to pneumococcal vaccine

We surveyed historical and laboratory data for 127 IgA-deficient patients (ages 2-67), referred to an immunology clinic; the commonest medical history was recurrent respiratory infections (50%), followed by autoimmunity (28%) asthma and allergy (13%). Fifty-two subjects have been given a pneumococcal vaccination; vaccine responses to 12 serotypes were significantly related to serum IgG2 levels (P = 0.004). Six immunized IgA/IgG2-deficient subjects produced insignificant amounts of antibodies to these pneumococcal serotypes; 10 others with normal IgG2 levels also had subnormal vaccine responses. IgA-deficient patients who had at least one B8 allele (n = 19) had a significantly greater response to this vaccine than the HLA-B8-negative subjects (n = 24) (P = 0.024). There was no relationship between a history of recurring infections and pneumococcal vaccine responses; HLA status was not related to a history of autoimmunity.

HLA and cytokine gene polymorphisms are independently associated with responses to hepatitis B vaccination

Variable immune responses to hepatitis B virus (HBV) infection and recombinant HBV vaccines have been associated with polymorphisms in several genes within the human leukocyte antigen (HLA) complex. Analyses of polymerase chain reaction (PCR)-based genotyping data from 164 North American adolescents vaccinated with recombinant HBV products confirmed that HLA-DRB1*07 (relative odds [RO] = 5.18, P <.0001) and human immunodeficiency virus type 1 (HIV-1) infection (RO = 3.91, P <.001) were both associated with nonresponse to full-dose vaccination. Further associations were observed with single nucleotide polymorphisms (SNPs) at the IL2 and IL4 loci along with insertion/deletion variants at the IL12B locus (P =.003-.01). Host genetic associations were independent of one another as well as other HLA (A, B, C, and DQB1) and cytokine gene (IL4R, IL6, IL10, and TNF) variants. Statistical adjustments for nongenetic factors (gender, ethnicity, age, HIV-1 infection, and vaccination protocols) did not substantially alter the strengths of the genetic relationships. The overall distribution pattern of genetic variations was similar between the analyzed vaccinees and additional adolescents (n = 292) from the same cohort. In conclusion, DRB1*07 (or a closely linked allele) and immunoregulatory cytokine gene polymorphisms correlate with variable immune response to recombinant HBV vaccines.

The antibody response to HBs antigen is regulated by coordinated Th1 and Th2 cytokine production in healthy neonates

A proportion of healthy neonates fail to produce protective levels of anti-HBs antibody following vaccination with recombinant hepatitis B vaccine. This study was undertaken to investigate contribution of Th1 and Th2 responses to anti-HBs antibody production and to explore the mechanism(s) of unresponsiveness to HBsAg in human neonates. Peripheral blood manonuclear cells (PBMCs) were isolated form 28 nonresponder (anti-HBs antibody <10 IU/l) and 25 responder neonates. The cells were stimulated in vitro with recombinant HBsAg and PHA mitogen and concentrations of IL-4, IL-10 and IFN-gamma were quantified in culture supernatants by sandwich ELISA. Our results demonstrated significantly increased production of all cytokines, including IL-4 (P < 0.001), IL-10 (P < 0.002) and IFN-gamma (P < 0.01) in responder compared to nonresponder vaccinees. No significant differences, however, were observed between the two groups of neonates in the levels of cytokines induced by PHA or secreted in absence of antigen and mitogen. Our findings suggest that unresponsiveness to recombinant HBsAg in healthy neonates is linked to inadequate secretion of both Th1 and Th2 cytokines.

Antigen-specific T cell response in infants after recombinant hepatitis B virus vaccination at birth: evaluation of T helper lymphocyte diversity

Recombinant hepatitis B virus antigen (rHBsAg)-specific CD4+ T cell clones (TCC) were isolated and expanded from the peripheral blood of nine children vaccinated at birth against the hepatitis B (HB) virus. Four of them responded with protective antibody production (responders), three subjects were unable to produce detectable antibody levels even after revaccination (nonresponders), and two infants produced antibodies only after revaccination (slow responders). TCC were then characterized for their ability to produce cytokines known to be important for T cell expansion (interleukin-2, IL-2) and/or effector functions (IL-4, IFN-gamma, IL-10). Results demonstrated that the frequency of rHBsAg-specific TCC in the samples of nonresponders was comparable to or higher than that in the samples of responders. Nevertheless, the majority of TCC obtained from responders or from slow responders before revaccination displayed the T helper 1 (T(H1))-dominant phenotype, while the majority of TCC obtained from nonresponders were nonpolarized T lymphocytes. After revaccination, the distribution of the different T(H) subsets in slow responders was heterogeneous. Overall, our present data suggest that an absence or delay in developing an rHBsAg-specific antibody response to vaccination is not associated with the capacity to generate an Ag-specific T cell response. However, compared to responders, nonresponding infants react to the rHBsAg vaccination with a reduced capacity to expand and differentiate toward polarized T(H) cells.

Analysis of T-cell receptor beta chain variable gene segment usage in healthy adult responders and nonresponders to recombinant hepatitis B vaccine

One to 10 per cent of healthy adult individuals do not produce protective levels of anti-hepatitis B surface (HBs) antibodies, following a standard vaccination protocol. Lack of an HBs antigen (Ag)-specific T-cell repertoire is amongst the possible defects, which may lead to humoral unresponsiveness and is the main objective of this study. We analysed TcR BV (T-cell receptor beta chain variable) gene usage in T lymphocytes from nine healthy adult responders and six nonresponders to recombinant HB vaccine, before and after booster vaccination. CD4+ and CD8+ T-cell populations were isolated from peripheral blood mononuclear cells by magnetic beads, and the expression of TcR BV genes in each population was investigated by reverse transcription polymerase chain reaction and hybridization with specific probe. When the usage of each TcR BV gene within CD4+ and CD8+ T cells of the responders was compared with that of nonresponders, statistically significant difference (P < 0.01) was noted for BV5S2-3 gene family in CD4+ T cells of nonresponders. Furthermore, individual vaccinees were shown to overexpress several TcR BV genes. To characterize the T-cell repertoire and determine their clonal nature, analysis of CDR3 length polymorphism was performed. Our results show that T-cell response to HBsAg is generally oligoclonal and involves multiple BV families. Furthermore, overexpressed individual TcR BV genes and CDR3 length distributions in response to HBsAg are subject-dependent. In conclusion, our results are not in line with the notion that defective TcR repertoire may be an explanation for unresponsiveness to recombinant HBsAg vaccine.

The antibody response to HBs antigen is regulated by coordinated Th1 and Th2 cytokine production in healthy neonates

A proportion of healthy neonates fail to produce protective levels of anti-HBs antibody following vaccination with recombinant hepatitis B vaccine. This study was undertaken to investigate contribution of Th1 and Th2 responses to anti-HBs antibody production and to explore the mechanism(s) of unresponsiveness to HBsAg in human neonates. Peripheral blood manonuclear cells (PBMCs) were isolated form 28 nonresponder (anti-HBs antibody <10 IU/l) and 25 responder neonates. The cells were stimulated in vitro with recombinant HBsAg and PHA mitogen and concentrations of IL-4, IL-10 and IFN-gamma were quantified in culture supernatants by sandwich ELISA. Our results demonstrated significantly increased production of all cytokines, including IL-4 (P < 0.001), IL-10 (P < 0.002) and IFN-gamma (P < 0.01) in responder compared to nonresponder vaccinees. No significant differences, however, were observed between the two groups of neonates in the levels of cytokines induced by PHA or secreted in absence of antigen and mitogen. Our findings suggest that unresponsiveness to recombinant HBsAg in healthy neonates is linked to inadequate secretion of both Th1 and Th2 cytokines.

Diminished Th1 and Th2 cytokine production in healthy adult nonresponders to recombinant hepatitis B vaccine

Vaccination of healthy adults with recombinant hepatitis B (rHB) vaccine fails to induce a protective antibody response in a proportion of individuals. Imbalanced T-helper (Th)1/Th2 response has been attributed to the lack of specific antibody response to rHB vaccine. In this study, in vitro production of interleukin (IL)-2, interferon (IFN)-gamma and IL-10 was investigated in Iranian healthy adults vaccinated with rHB vaccine. Peripheral blood mononuclear cells (PBMC) were isolated from 18 high responders and eight nonresponders and stimulated with rHB antigen or phytohaemaglutinin (PHA) mitogen. The cytokines were quantitated in culture supernatants by sandwich enzyme-linked immunosorbent assay (ELISA). Our results demonstrated a significant decrease in the production of IL-2, IFN-gamma and IL-10 (P < 0.005) in response to rHB antigen. The levels of all cytokines induced by PHA were similarly represented in both groups of vaccinees. These findings suggest that unresponsiveness to rHB vaccine may be owing to inadequate Th1- and Th2-like cytokine production.

Enumeration of hepatitis B surface antigen-specific B lymphocytes in responder and non-responder normal individuals vaccinated with recombinant hepatitis B surface antigen

Determination of the frequency of specific B lymphocytes has important implications for investigation of the immune response to different antigens and pathogens. Unresponsiveness to some viruses and antigens, such as hepatitis B virus (HBV) and its surface antigen (HBsAg), has been attributed to lack or insufficient production of the specific B-cell repertoire. In this study, peripheral blood B lymphocytes of 45 adult normal individuals vaccinated with recombinant hepatitis B vaccine were transformed with Epstein-Barr virus (EBV) and cultured at different dilutions on human fetal fibroblasts as a feeder layer. The vaccinees were classified into good, poor and non-responder groups. Following 2 to 3 weeks of incubation, culture supernatants were collected from wells containing transformed and proliferating B lymphocytes. The supernatants were subsequently screened for the presence of total immunoglobulin and antibody to HBsAg (anti-HBs) by enzyme-linked immunosorbent assay (ELISA). Accordingly, positive and negative wells were enumerated in each plate and the frequency of B lymphocytes producing anti-HBs antibody was estimated based on the Poisson statistical analysis. The total number of CD19+ B lymphocytes were counted in the peripheral blood of all subjects by flow cytometry. Our results demonstrated a similar precursor frequency of specific B lymphocytes in all subject groups before vaccine administration (< 2 x 10(-5)). Following vaccination, however, a significant increase in the number of specific B lymphocytes was observed in good-responder (1.5 x 10(-4)) and to a lesser extent poor-responder (3.5 x 10(-5)) individuals, but not in non-responders. These findings suggest a defect in either the primary B-cell repertoire or helper T-cell function in non-responder individuals.

Characterization of hepatitis B virus surface antigen-specific CD4+ T cells in hepatitis B vaccine non-responders

AIM

To study the mechanisms of hepatitis B vaccine non-response, we examined hepatitis B virus surface antigen (HBsAg)-induced proliferation of peripheral blood mononuclear cells (PBMC) obtained from hepatitis B (HB) vaccinees.

METHODS

Subsequently, we have examined the features of HBsAg-reactive CD4+ T cells in HB vaccine non-responders (NR). Based on serum antibodies to HBsAg (anti-HBs) titers, we divided these vaccinees into three groups: high responder (HR), middle responder (MR) and non-responder (NR), and examined HBsAg-induced proliferation of their PBMC.

RESULTS

We found that the in vitro response of PBMC to stimulation with HBsAg was correlated with their serum anti-HBs titer (mean stimulation index was 10.71 in HR, 4.37 in MR and 1.96 in NR). However, by the deletion of CD8+ T cells, the increased response was observed in two of four NRs.

CONCLUSIONS

The present results have also shown that at least four distinct HBsAg-reactive CD4+ clones existed (variable gene of T cell receptor beta (V beta) 17 + clone restricted with HLA-DR locus (DR4), V beta 8 + clone restricted with HLA-DQ locust (DQ7), and both V beta 5.1 + clone and V beta 20 + clone restricted with either DR9 or DQ3) in NRs. The results demonstrated that heterogeneous HBsAg-reactive CD4 clones existed in some HB vaccine NRs.

Results of hepatitis B vaccination in sarcoidosis

BACKGROUND

Sarcoidosis is known to be associated with defects in cellular immunity, especially in reference to T helper lymphocytes. Anergy to a tuberculin skin test is most characteristic of this disease.

OBJECTIVES

To further the data on impaired immunity, we studied the antibody response to hepatitis B vaccination in patients with sarcoidosis.

METHODS

Serologic markers of hepatitis B virus (HBV) (HBsAg, anti-HBs, anti-HBc) were studied in 40 patients with sarcoidosis (32 female, 8 male; mean age: 45 +/- 11 years, range: 25-66 years) with a mean duration of disease of 6 years. While all the markers were negative in 22 patients (55%), 2 had isolated anti-HBc positivity and 16 had both anti-HBc and anti-HBs antibodies. Thirty-five age- and sex-matched healthy subjects were studied as controls. Recombinant HBV vaccines (Genhevac B Pasteur, 20 microg) were administered (at 0, 1, and 6 months) to 16 of the seronegative cases and the controls and antibody titres were measured 1 month after the last dose. The tuberculin skin test was negative in all cases.

RESULTS

While none of the vaccinees in the diseased group responded, the control group yielded an antibody response rate of 85. 7% (30/35), with a mean titre of 257.9 mIU/ml.

CONCLUSIONS

Patients with sarcoidosis were invariably unresponsive to standard vaccination, while some of the diseased subjects had already mounted a natural antibody response, either before or after the development of the original disease. Cellular immunodeficiency in sarcoidosis could be a suitable model for studying immunological interactions between HBV and the host.

Increment of recombinant hepatitis B surface antigen-specific T-cell precursors after revaccination of slow responder children

The aim of the study was to investigate the in vitro T-cell response to recombinant hepatitis B (rHBsAg) in a group of children (defined as "slow responders") vaccinated at birth, presenting antibody levels < 10 mIU/ml after the vaccination schedule, and developing anti-rHBs antibodies after revaccination. T-cell mediated immune response towards rHBsAg was evaluated in 35 healthy children in "bulk" culture experiments (19 responders and 16 slow responders) and by limiting dilution analysis (nine responders and five slow responders) to quantify the frequency of proliferating T lymphocyte-precursors (PTL-p). Before the booster dose, lymphocytes from slow responder children failed to proliferate to rHBsAg, while a normal proliferation was observed in all responders. A statistically significant difference in rHBsAg-specific PTLp frequencies was observed between the two groups. Among the slow responder group, a significant increase of PTLp was observed after the supplementary vaccine dose.Nevertheless, PTLp frequencies remained significantly lower than those measured in responders. These results suggest a role for follow-up of slow responder children over time, in order to perform booster vaccination when inadequate anti-HBs titre is present.

Fas-mediated apoptosis eliminates B cells that acquire self-reactivity during the germinal center response to NP

C57Bl/6 mice with the lpr mutation of Fas (CD95) were tested for deviation from the genetically restricted antibody response to the hapten 4-hydroxy-3-nitrophenyl acetyl (NP). lambda1+ germinal centers (GC) with the canonical v186.2 V(H) gene element develop in lpr/lpr mice with the same time course as in wild-type (+/+) mice. In contrast to +/+ mice, however, lambda1+ GC persist in the spleens of lpr/lpr mice 25 days after immunization. Virtually all of the lambda1+ GC are reactive with NP 10 days after immunization. Sixteen days after immunization, however, many of the lambda1+ GC are not reactive with NP, and few of the lambda1+ GC are reactive with NP 25 days after immunization. The V(H) gene elements of three lambda1+NP- GC 25 days after immunization are derived by somatic mutation of v186.2, but have lost reactivity with NP. The mutated VDJs from these GC react with cells in spleen sections from +/+ and lpr/lpr mice, indicating that they represented secondary antibody responses induced by self antigens that are available as presented antigen. These data indicate that Fas-mediated apoptosis serves to eliminate a (limited) population of B cells that acquire reactivity to "self antigens" by somatic mutation of VDJs in the GC.

Complex cytokine responses to hepatitis B surface antigen and tetanus toxoid in responders, nonresponders and subjects naive to hepatitis B surface antigen

Some human subjects vaccinated with hepatitis B surface antigen (HBsAg) do not produce antibodies to the vaccine (nonresponders). The mechanism for nonresponse is unknown. To understand the response and nonresponse to nominal antigens better, we determined the level and kinetics of cytokine secretion in response to HBsAg and tetanus toxoid (TT) by peripheral blood mononuclear cells (PBMC) in vitro from HBsAg vaccine responders and nonresponders and from individuals naive to HBsAg. Proliferating PBMC secreted peak levels of interleukin-2 (IL-2) at 2 days and peak levels of tumor necrosis factor-beta (TNF-beta), interferon-gamma (IFN-gamma), IL-4 and IL-10 at 3-6 days post-stimulation. In contrast, nonproliferating PBMC (whether from nonresponders, naive subjects or weak responders) did not produce detectable levels of TNF-beta or IFN-gamma, nor was IL-4 or IL-10 produced significantly, and that produced had a different kinetic profile from that of proliferating PBMC. HBsAg-specific cytokine production by PBMC from strong responders broadly paralleled their cytokine responses to TT. Cellular cytokine mRNA levels measured by reverse transcriptase-polymerase chain reaction corroborated the secreted cytokine results. The anti-HBsAg- and anti-TT-specific T cell cytokine responses were mixed Th(1/2)-like and donor-specific. An HBsAg-specific cytokine response, but not a TT-specific cytokine response, was completely missing in nonresponders. These data suggest that the T cell defect of HBsAg nonresponse is not due to a skewed cytokine profile.

Cationic lipid DC-Chol induces an improved and balanced immunity able to overcome the unresponsiveness to the hepatitis B vaccine

Th1 and Th2 immune responses against antigens can be modulated by the use of adjuvants. Since antibody isotypes (IgG1 and IgG2a) and cytokines induced may reflect the Th differentiation taking place during the immune response, the humoral and cellular immune responses induced in mice against hepatitis B virus surface antigen (HBsAg) were examined when the antigen was either adsorbed to aluminum hydroxyde or administered with a new adjuvant the cationic lipid 3beta-[N-(N',N'-dimethylaminoethane)carbamoyl]cholesterol (DC-Chol). The use of DC-Chol increased antibody responses in responding BALB/c mice, induced more consistent IgG1 and IgG2a antibody responses in OF1 mice and overcame the nonresponse to HBsAg in B10.M mice. Furthermore, DC-Chol was able to induce cellular immune responses to HBsAg. The DC-Chol induced a balanced Th1/Th2 response, which enabled mice to overcome the inherited unresponsiveness to HBsAg encountered with aluminum-adjuvanted vaccine. Thus, the DC-Chol provides a signal to switch on both Th1 and Th2 responses, which may have important implications for vaccination against hepatitis B virus, as well as for enhancing weak immunogenicity of other recombinant purified antigens in a nonresponder population.