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Background In the context of early vaccine trials aimed at evaluating the safety profile of novel vaccines, abnormal haematological values, such as neutropenia, are often reported. It is therefore important to evaluate how these trials should be planned not to miss potentially important safety signals, but also to understand the implications and the clinical relevance. Methodology We report and discuss the results from five clinical trials (two with a new Shigella vaccine in the early stage of clinical development and three with licensed vaccines) where the absolute neutrophil counts (ANC) were evaluated before and after vaccination. Additionally, we have performed a systematic review of the literature on cases of neutropenia reported during vaccine trials to discuss our results in a more general context. Principal Findings Both in our clinical trials and in the literature review, several cases of neutropenia have been reported, in the first two weeks after vaccination. However, neutropenia was generally transient and had a benign clinical outcome, after vaccination with either multiple novel candidates or well-known licensed vaccines. Additionally, the vaccine recipients with neutropenia frequently had lower baseline ANC than non-neutropenic vaccinees. In many instances neutropenia occurred in subjects of African descent, known to have lower ANC compared to western populations. Conclusions It is important to include ANC and other haematological tests in early vaccine trials to identify potential safety signals. Post-vaccination neutropenia is not uncommon, generally transient and clinically benign, but many vaccine trials do not have a sampling schedule that allows its detection. Given ethnic variability in the level of circulating neutrophils, normal ranges taking into account ethnicity should be used for determination of trial inclusion/exclusion criteria and classification of neutropenia related adverse events. Trial registration ClinicalTrials.gov NCT02017899, NCT02034500, NCT01771367, NCT01765413, NCT02523287

Background The malaria vaccine candidate RTS,S/AS01 (GSK Vaccines) induces high IgG concentration against the circumsporozoite protein (CSP) of Plasmodium falciparum. In human vaccine recipients circulating anti-CSP antibody concentrations are associated with protection against infection but appear not to be the correlate of protection. However, in a humanized mouse model of malaria infection prophylactic administration of a human monoclonal antibody (MAL1C), derived from a RTS,S/AS01-immunized volunteer, directed against the CSP repeat region, conveyed full protection in a dose-dependent manner suggesting that antibodies alone are able to prevent P. falciparum infection when present in sufficiently high concentrations. A competition ELISA was developed to measure the presence of MAL1C-like antibodies in polyclonal sera from RTS,S/AS01 vaccine recipients and study their possible contribution to protection against infection. Results MAL1C-like antibodies present in polyclonal vaccine-induced sera were evaluated for their ability to compete with biotinylated monoclonal antibody MAL1C for binding sites on the capture antigen consisting of the recombinant protein encompassing 32 NANP repeats of CSP (R32LR). Serum samples were taken at different time points from participants in two RTS,S/AS01 vaccine studies (NCT01366534 and NCT01857869). Vaccine-induced protection status of the study participants was determined based on the outcome of experimental challenge with infected mosquito bites after vaccination. Optimal conditions were established to reliably detect MAL1C-like antibodies in polyclonal sera. Polyclonal anti-CSP antibodies and MAL1C-like antibody content were measured in 276 serum samples from RTS,S/AS01 vaccine recipients using the standard ELISA and MAL-1C competition ELISA, respectively. A strong correlation was observed between the results from these assays. However, no correlation was found between the results of either assay and protection against infection. Conclusions The competition ELISA to measure MAL1C-like antibodies in polyclonal sera from RTS,S/AS01 vaccine recipients was robust and reliable but did not reveal the elusive correlate of protection. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1596-8) contains supplementary material, which is available to authorized users.

Anabolic androgenic steroids are prohibited by the World Anti-Doping Agency because of their adverse health and performance enhancing effects. Effective control of their misuse by detection in urine requires knowledge about their metabolism. In case of designer steroids, ethical objections limit the use of human volunteers to perform excretion studies. Therefore the suitability of alternative models needs to be investigated. In this study pooled human liver microsomes (HLM) and an uPA(+/+)-SCID chimeric mouse model were used to examine the metabolism of the designer steroid prostanozol as a reference standard. Metabolites were detected by GC-MS (full scan) and LC-MS/MS (precursor ion scan). In total twenty-four prostanozol metabolites were detected with the in vitro and in vivo metabolism studies, which could be grouped into two broad classes, those with a 17-hydroxy- and those with a 17-keto-substituent. Major first phase metabolic sites were tentatively identified as C-3'; C-4 and C-16. Moreover, 3'- and 16β-hydroxy-17-ketoprostanozol could be unequivocally identified, since authentic reference material was available, in both models. Comparison with published data from humans showed a good correlation, except for phase II metabolism. As metabolites were in contrast to the human studies predominantly present in the free fraction. Two types of metabolites ((di)hydroxylated prostanozol metabolites) that have not been described before could be confirmed in a real positive doping control sample. Hence, the results provide further evidence for the applicability of chimeric mice and HLM to perform metabolism studies of designer steroids.

© 2016 Lazarus et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Avian influenza continues to circulate and remains a global health threat not least because of the associated high mortality. In this study antibody persistence, booster vaccine response and cross-clade immune response between two influenza A(H5N1) vaccines were compared. Participants aged over 18-years who had previously been immunized with a clade 1, A/Vietnam vaccine were re-immunized at 6-months with 7.5 μg of the homologous strain or at 22-months with a clade 2, alum-adjuvanted, A/Indonesia vaccine. Blood sampled at 6, 15 and 22-months after the primary course was used to assess antibody persistence. Antibody concentrations 6-months after primary immunisation with either A/Vietnam vaccine 30 μg alum-adjuvanted vaccine or 7.5 μg dose vaccine were lower than 21-days after the primary course and waned further with time. Re-immunization with the clade 2, 30 μg alum-adjuvanted vaccine confirmed cross-clade reactogenicity. Antibody crossreactivity between A(H5N1) clades suggests that in principle a prime-boost vaccination strategy may provide both early protection at the start of a pandemic and improved antibody responses to specific vaccination once available.

Objective: Direct-acting antivirals (DAAs) inhibit hepatitis C virus (HCV) infection by targeting viral proteins that play essential roles in the replication process. However, selection of resistance-associated variants (RAVs) during DAA therapy has been a cause of therapeutic failure. In this study, we wished to address whether such RAVs could be controlled by the co-administration of host-targeting entry inhibitors that prevent intrahepatic viral spread. Design: We investigated the effect of adding an entry inhibitor (the anti-scavenger receptor class B type I mAb1671) to a DAA monotherapy (the protease inhibitor ciluprevir) in human-liver mice chronically infected with HCV of genotype 1b. Clinically relevant non-laboratory strains were used to achieve viraemia consisting of a cloud of related viral variants (quasispecies) and the emergence of RAVs was monitored at high resolution using next-generation sequencing. Results: HCV-infected human-liver mice receiving DAA monotherapy rapidly experienced on-therapy viral breakthrough. Deep sequencing of the HCV protease domain confirmed the manifestation of drug-resistant mutants upon viral rebound. In contrast, none of the mice treated with a combination of the DAA and the entry inhibitor experienced on-therapy viral breakthrough, despite detection of RAV emergence in some animals. Conclusions: This study provides preclinical in vivo evidence that addition of an entry inhibitor to an anti-HCV DAA regimen restricts the breakthrough of DAA-resistant viruses. Our approach is an excellent strategy to prevent therapeutic failure caused by on-therapy rebound of DAA-RAVs. Inclusion of an entry inhibitor to the newest DAA combination therapies may further increase response rates, especially in difficult-to-treat patient populations.

Background. An adjuvanted recombinant varicella zoster virus (VZV) subunit vaccine is being developed for the prevention of herpes zoster and its complications. Methods. In a phase I/II, open-label, randomized, parallel-group study, older adults (50-70 years) received 2 doses 2 months apart of an adjuvanted recombinant glycoprotein E vaccine (HZ/su; n = 45), a live attenuated Oka strain VZV vaccine (OKA; n = 45), or HZ/su and OKA administered concomitantly (n = 45). To evaluate safety prior to administration in older adults, young adults (18-30 years) were vaccinated with 2 doses 2 months apart of HZ/su (n = 10) or OKA (n = 10). Safety and immunogenicity were assessed up to 42 months for older adults immunized with HZ/su and up to 12 months for all others. Results. Few grade 3 events and no severe adverse events were reported. Fatigue, myalgia, headache, and injection site pain were the most common solicited reactions for HZ/su and occurred more frequently than with OKA. CD4(+) T-cell and humoral immune responses were much higher with HZ/su than with OKA and remained elevated until 42 months. Addition of OKA to HZ/su did not increase immunogenicity. Conclusions. In this study, HZ/su adjuvanted subunit vaccine was well tolerated and more immunogenic than a live attenuated VZV vaccine. Clinical Trial registration. NCT00492648 and NCT00492648.

This study assessed antibody persistence and immune memory to hepatitis B vaccine 20 y after priming with a recombinant hepatitis B virus (HBV) vaccine during infancy. Infants were vaccinated according to a 0, 1, 6 mo schedule with or without simultaneous administration of hepatitis B immunoglobulin (HBIg). Half of the subjects enrolled received an interim booster dose at year 5 (boosted) group, whereas the other half of the subjects enrolled did not (unboosted group). Antibody persistence was assessed until year 20. Immune memory was assessed by administration of a final HBV vaccine challenge dose at year 20 in a second study. At year 20, anti-HBs antibody concentration ≥ 10 mIU/ml rates and GMCs were higher among subjects in the boosted group (84.2% [16/19]; 95%CI: 60.4–96.6) when compared with those in the unboosted group [44.0% (11/25)]; 95% CI: 24.4–65.1). After the HBV vaccine challenge dose at year 20, anti-HBs anamnestic response for subjects in the unboosted and boosted groups was observed in 93.1% (95% CI: 77.2–99.2) and 100% (95% CI: 76.8–100) of subjects, respectively. The mean anti-HBs antibody concentration (GMC) was 562.0 mIU/ml (292.5–1079.7 mIU/ml) post administration of the challenge dose; this is a 28.5 fold increase from the pre- to post-challenge dose administration at year 20. This study demonstrates persistence of anti-HBs antibodies and presence of immune memory following hepatitis B vaccination for up to at least 20 y in Thailand. Immune memory was demonstrated for virtually all subjects, regardless whether they received they had received the additional HBV dose or not. The challenge dose at year 20 was well tolerated and a robust response was demonstrated. ClinicalTrials.gov Identifier: NCT00240526, NCT00774995.

Infections with HCV represent a major global health problem. End-stage liver disease caused by chronic HCV infection is the most common indication for liver transplantation. Limited efficacy and severity of side effects hamper the use of pegylated interferon combined with ribavirin in a liver transplant setting. Therefore, new therapeutic options should be made available. Viral entry, the first step of the viral life cycle, represents an interesting target for therapeutic intervention. Understanding the mechanisms of viral entry is necessary to define the viral and cellular factors involved. In this review, we summarize these factors, highlight their potential as therapeutic targets and review the current (pre)clinical development of molecules that interfere with HCV entry.

Background Group B streptococcus (GBS) is a leading cause of sepsis and meningitis in early infancy. Substantial data demonstrate that women with higher levels of circulating antibody against the capsular polysaccharide (CPS) deliver infants at reduced risk of GBS infection, which serves as the basis for vaccine design. This study evaluates two different dosages, two injection schedules and three formulations of an investigational trivalent (serotypes Ia, Ib and III) CRM 197 -glycoconjugate GBS vaccine in healthy, non-pregnant women. Methods 678 healthy non-pregnant women received one or two injections of one of two dosages (5/5/5 μg or 20/20/20 μg) of the investigational vaccine, formulated with or without aluminum hydroxide (Enrolment Group 1), or with full or half dosages of MF59 ® (Enrolment Group 2); or a placebo (Enrolment Groups 1 and 2). Geometric mean serotype-specific antibody concentrations (GMCs) at Days 61 (Enrolment Group 1) and 361 (both Groups) were analyzed to select a formulation suitable for pregnant or non-pregnant women, respectively. Solicited adverse reactions were recorded up to Day 7 and adverse events (AEs) were recorded throughout the study. Results Rates of reported AEs were similar across all groups. Higher rates of local reactogenicity were seen in adjuvanted vaccine groups compared with non-adjuvanted vaccine (or placebo) groups. All vaccine groups elicited higher GMCs than placebo; differences between treatments were not statistically significant, indicating no additional potential benefit of higher antigen content, addition of adjuvant, or a second dose. Conclusions All GBS vaccine formulations induced a persistent antibody response and showed similar immunogenicity profiles ( NCT01150123 ).

The chimeric uPA+/+-SCID mouse model, transplanted with human hepatocytes, was previously validated as an alternative tool to study in vivo the human steroid metabolism. This humanized mouse model was now applied, in the framework of anti-doping research, to test different nutritional supplements containing steroids. These steroids, intentionally or accidentally added to a nutritional supplement, usually are derivatives of testosterone. Information about the metabolism of these derivatives, which is important to assure their detection, is quite limited. However, due to ethical constraints, human volunteers cannot be used to perform experimental excretion studies. Therefore the chimeric mice were selected to perform three separated excretion studies with superdrol (methasterone), promagnon and also methylclostebol. The urine of the humanized mice was collected 24 h after a single dose administration and analyzed by gas chromatography–mass spectrometry (GC–MS). The results indicated the presence of several metabolites including a 3-keto reduced metabolite and numerous hydroxylated metabolites. Also phase 2 metabolism was investigated to update the complete picture of their metabolism.

The influence of AS03 A , a tocopherol oil-in-water emulsion-based adjuvant system, on humoral and cell-mediated responses to A/California/7/2009 H1N1 pandemic vaccine was investigated. In two observer-blind studies, a total of 261 healthy adults aged 18 to 60 years were randomized to receive either AS03 A -adjuvanted H1N1 vaccine containing 3.75 μg hemagglutinin (HA) or nonadjuvanted H1N1 vaccine containing 15 or 3.75 μg HA on days 0 and 21. Hemagglutination inhibition (HI) antibody and T-cell responses were analyzed up to day 42. A first dose of AS03 A -adjuvanted vaccine (3.75 μg HA) or nonadjuvanted vaccine (15 μg HA) induced HI responses of similar magnitudes that exceeded licensure criteria (e.g., 94 to 100% with titers of ≥40). A lower response following 3.75 μg HA without adjuvant was observed (73% with titers of ≥40). Following a second dose, geometric mean HI titers at day 42 were higher for AS03 A -adjuvanted vaccine (636 and 637) relative to nonadjuvanted vaccine (341 for 15 μg HA and 150 for 3.75 μg HA). Over the 42-day period, the increase in frequency of A/H1N1/2009-specific CD4 + T cells was significantly higher in the adjuvanted group than in the nonadjuvanted group. There was no evidence of correlation between baseline CD4 + T-cell frequencies and day 21 HI antibody titers, while there was some correlation ( R = 0.35) between day 21 CD4 + T-cell frequencies and day 42 HI titers. AS03 A adjuvant enhanced the humoral and CD4 + T-cell-mediated responses to A/H1N1/2009 vaccine. Baseline A/H1N1/2009-specific CD4 + T-cell frequencies did not predict post-dose 1 antibody responses, but there was some correlation between post-dose 1 CD4 + T-cell frequencies and post-dose 2 antibody responses.

Vaccination against hepatitis B virus (HBV) immediately after birth prevents neonatal infection by vertical transmission from HBV carrier mothers. There is an ongoing debate whether infant vaccination is sufficient to protect against infection when exposed to HBV later in life. We studied 222 Thai infants born to HBsAg -/+ and HBeAg -/+ mothers who were vaccinated with recombinant hepatitis B vaccine at 0-1-2-12 months of age. A subset of 100 subjects received a booster dose at age 5 years. Blood samples collected yearly for 20 years were examined for anti-HBs antibodies and serological markers of hepatitis B infection (anti-HBc, HBsAg, and in selected cases HBeAg, anti-HBe, HBV DNA). During the 20-year follow-up, no subject acquired new chronic HBV infection or clinical hepatitis B disease. During the first decade, possible subclinical breakthrough HBV infection (anti-HBc seroconversion) was only observed in subjects born to HBsAg +/HBeAg + mothers (6/49 [12.2%]). During the second decade, breakthrough HBV infections were detected in all groups (18/140 [12.8%]). Increases in anti-HBs concentrations that were unrelated to additional HBV vaccination or infection were detected in approximately 10% of subjects in each decade. Primary infant vaccination with a recombinant hepatitis B vaccine confers long-term protection against clinical disease and new chronic hepatitis B infection despite confirmed hepatitis B exposure.

Background: Vaccine-induced antibodies to envelope proteins frequently cause HIV seroconversion in uninfected recipients of HIV vaccine candidates and may thus have an impact on the vaccinee’s ability to donate blood or acquire a life insurance policy. Objective: To determine the occurrence of positive test results when commonly used HIV immunoassays are used to screen sera of HIV-uninfected volunteers who received an adjuvanted HIV-1 vaccine candidate containing HIV-1 antigens p24, reverse transcriptase, Nef and p17. Study design: Sera of 50 subjects who received this polyprotein vaccine in a single center in Belgium were tested with 6 HIV screening assays and 1 confirmation test. All samples were drawn one year after the administration of the first of two vaccine doses given with one month interval. Results: Forty-five (90%) sera showed a positive test result in at least one of the 7 HIV tests used. The positivity rates were 88% in the Elecsys HIV Combi assay, 74% in the ADVIA Centaur EHIV and 48% in the PRISM HIV O Plus assay. Conclusions: Interpretation of HIV test results is becoming increasingly complex with the growing number of volunteers participating in prophylactic HIV vaccine trials worldwide and the rising number of viral antigens included in these vaccine candidates. The results of this study in recipients of a highly immunogenic adjuvanted polyprotein HIV vaccine candidate devoid of envelope proteins, illustrate the increasing need for approaches that can discriminate HIV infection-induced antibodies from those elicited by a vaccine. © 2011 Elsevier B.V. All rights reserved.

A novel AS01-adjuvanted HIV-1 vaccine candidate consisting of a recombinant fusion protein (F4) containing 4 HIV-1 clade B antigens (Gag p24, Pol reverse transcriptase [RT], Nef and Gag p17) induced long-lasting, polyfunctional cross-reactive CD4+ T-cell responses in HIV-seronegative volunteers., Background. This phase I/II partially blinded, randomized, dose-ranging study assessed the safety and immunogenicity of a novel human immunodeficiency virus type 1 (HIV-1) vaccine candidate consisting of a recombinant fusion protein (F4) containing 4 HIV-1 clade B antigens (Gag p24, Pol reverse transcriptase, Nef, and Gag p17) adjuvanted with AS01 in HIV-seronegative volunteers. Methods. Two doses of the recombinant F4 protein (10, 30, or 90 μg/dose), adjuvanted with AS01 or reconstituted with water for injection, were administered 1 month apart to 180 healthy volunteers aged 18–40 years. F4-specific CD4+ T cell responses were measured using intracellular cytokine staining after in vitro stimulation by overlapping peptide pools covering the 4 individual antigens. Results. Reactogenicity was higher during the 7-day period after each vaccine dose in the adjuvanted than in the nonadjuvanted groups. In the adjuvanted groups, the overall immune response rate was high after the second vaccine dose, with highest responder rates seen in the 10-μg F4/AS01 group (100% to 3 HIV-1 antigens and 80% to all 4 HIV-1 antigens). High and long-lasting CD4+ T cell frequencies were observed (up to a median value of 1.2% F4-specific CD4+ T cells at day 44), with strongest responses directed against reverse transcriptase. Antigen-specific CD4+ T cells exhibited a polyfunctional phenotype, expressing at least CD40 ligand and interleukin 2, often in combination with tumor necrosis factor α and/or interferon γ. Vaccine-induced CD4+ T cell responses were broadly cross-reactive to all 4 antigens derived from HIV-1 clades A and C. Conclusions. These results support further clinical investigation of this HIV-1 vaccine candidate both in a prophylactic setting (alone, in conjunction with an envelope-based antigen or in combination with other vaccine approaches in a heterologous prime-boost regimen) and as a potentially disease-modifying therapeutic vaccine in HIV-1–infected subjects. Clinical trials registration. NCT00434512.

Infections caused by hepatitis C virus (HCV) are a significant world health problem for which novel therapies are in urgent demand. The polymerase of HCV is responsible for the replication of viral genome and has been a prime target for drug discovery efforts. Here, we report on the further development of tetracyclic indole inhibitors, binding to an allosteric site on the thumb domain. Structure-activity relationship (SAR) studies around an indolo-benzoxazocine scaffold led to the identification of compound 33 (MK-3281), an inhibitor with good potency in the HCV subgenomic replication assay and attractive molecular properties suitable for a clinical candidate. The compound caused a consistent decrease in viremia in vivo using the chimeric mouse model of HCV infection.

This randomized double-blind study aimed to determine the safety and immunogenicity of a gp120/NefTat candidate human immunodeficiency virus type 1 (HIV-1) vaccine formulated with one of three different Adjuvant Systems (AS02(A), AS02(V) and AS01(B)) in healthy HIV-seronegative adults. All vaccine formulations induced strong HIV-specific CD4(+) T-cell responses characterized by high lymphoproliferative capacity and IL-2 production that were still detectable 18 months after last immunization, with strongest responses seen in the AS01(B) group. Broad coverage was demonstrated against gp120, and to a lesser extent Nef, derived from the most common circulating clades (B, C and circulating recombinant form [CRF]-01). All vaccine formulations exhibited acceptable safety and reactogenicity profiles. The demonstration of superior CD4(+) T-cell induction by AS01(B) provides important guidance for future HIV vaccine development.

In order to study the hepatitis C virus (HCV) epidemiology in Flanders, Belgium, the HCV genotype of 2,301 patients diagnosed with HCV between 2001 and 2009 was determined. HCV genotyping was conducted using the Versant LiPA 1.0 or Versant LiPA 2.0 assay. To explore the transmission history of a remarkable cluster of the rarely found HCV genotype 5a, face-to-face interviews based on detailed questionnaires and maximum likelihood phylogenetic analysis were performed. HCV genotype 1 was the most prevalent genotype in all provinces, followed by HCV genotype 3 in East Flanders, Antwerp, Flemish Brabant and Limburg. In Brussels, HCV genotype 4 was the second most prevalent genotype. This observation is due to the immigration of patients from the Middle East and Africa. Remarkably, a cluster of HCV genotype 5a was found in West Flanders, where it represents the second most prevalent genotype, accounting for 26.2% of HCV infections. We could not identify one major transmission source explaining the whole HCV genotype 5a epidemic. Instead, several smaller possible transmission chains were identified and confirmed phylogenetically. Overall, the HCV genotype 5a epidemic in West Flanders seems to be mainly associated with blood transfusion and unsafe medical practices.

The key objective of vaccination is the induction of an effective pathogen-specific immune response that leads to protection against infection and/or disease caused by that pathogen, and that may ultimately result in its eradication from humanity. The concept that the immune response to pathogen antigens can be improved by the addition of certain compounds into the vaccine formulation was demonstrated about one hundred years ago when aluminium salts were introduced. New vaccine technology has led to vaccines containing highly purified antigens with improved tolerability and safety profiles, but the immune response they induce is suboptimal without the help of adjuvants. In parallel, the development of effective vaccines has been facing more and more important challenges linked to complicated pathogens (e.g. malaria, TB, HIV, etc.) and/or to subjects with conditions that jeopardize the induction or persistence of a protective immune response. A greater understanding of innate and adaptive immunity and their close interaction at the molecular level is yielding insights into the possibility of selectively stimulating immunological pathways to obtain the desired immune response. The better understanding of the mechanism of 'immunogenicity' and 'adjuvanticity' has prompted the research of new vaccine design based on new technologies, such as naked DNA or live vector vaccines and the new adjuvant approaches. Adjuvants can be used to enhance the magnitude and affect the type of the antigen-specific immune response, and the combination of antigens with more than one adjuvant, the so called adjuvant system approach, has been shown to allow the development of vaccines with the ability to generate effective immune responses adapted to both the pathogen and the target population. This review focuses on the adjuvants and adjuvant systems currently in use in vaccines, future applications, and the remaining challenges the field is facing.

An influenza vaccine with cross-immunogenic potential could play a key role in pandemic mitigation by promoting a rapid immune response to infection and/or subsequent vaccination with strains drifted from the primary vaccine strain. Here we assess the role of AS03(A) (an oil-in-water emulsion based Adjuvant System containing tocopherol) in this prime-boost concept using H5N1 as a model shift influenza antigen. In this open, non-randomised study (NCT00506350; an extension of an earlier randomised study) we assessed immunogenicity in nine groups of 35-50 volunteers aged 19-61 years following administration of AS03(A)-adjuvanted split-virion H5N1 vaccine containing 3.75mug of haemagglutinin (HA) from the A/Indonesia/5/2005(IBCDC-RG2) clade 2.1 strain. A single booster dose of vaccine was administered to four groups primed 14 months previously with different HA levels of AS03(A)-adjuvanted clade 1 A/Vietnam/1194/2004 H5N1 vaccine. Two booster doses (given 21 days apart) were administered to four groups primed 14 months previously with different HA levels of non-adjuvanted A/Vietnam/1194/2004 H5N1 vaccine and also to a control group of un-primed subjects. In individuals primed 14 months earlier with AS03(A)-adjuvanted A/Vietnam/1194/2004 vaccines, a single booster dose of AS03(A)-adjuvanted A/Indonesia/5/2005 induced rapid immune responses (licensure criteria met in 7-14 days) comparable to that observed in the un-primed control group following two doses of adjuvanted vaccine. In contrast, individuals primed with non-adjuvanted formulations exhibited minimal immune responses which, even after two doses, were unexpectedly much lower than that observed in un-primed subjects. AS03(A) enhances the initial priming effect of pandemic influenza vaccination enabling a rapid humoral response to single dose boosting with a heterologous strain at 14 months. In contrast, priming without adjuvant appears to inhibit the response to subsequent vaccination with a heterologous strain. These findings should guide the development of vaccines to combat the present influenza A/H1N1 pandemic.

Hepatitis B virus (HBV) infections represent a global health problem, since these account for 350 million chronic infections worldwide that result in 500 000-700 000 deaths each year. Control of viral replication and HBV-related disease and mortality are of utmost importance. Because the currently available antiviral therapies all have major limitations, new strategies to treat chronic HBV infection are eagerly awaited. Six single-domain antibodies (VHHs) targeting the core antigen of HBV (HBcAg) have been generated and three of these bound strongly to HBcAg of both subtype ayw and adw. These three VHHs were studied as intrabodies directed towards the nucleus or the cytoplasm of a hepatoma cell line that was co-transfected with HBV. A speckled staining of HBcAg was observed in the cytoplasm of cells transfected with nucleotropic VHH intrabodies. Moreover, an increased intracellular accumulation of hepatitis B e antigen (HBeAg) and a complete disappearance of intracellular HBcAg signal were observed with nuclear targeted HBcAg-specific VHHs. These results suggest that HBcAg-specific VHHs targeted to the nucleus affect HBcAg and HBeAg expression and trafficking in HBV-transfected hepatocytes.

Anabolic androgenic steroids are considered to be doping agents and are prohibited in sports. Their metabolism needs to be elucidated to allow for urinary detection by gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS). Steroid metabolism was assessed using uPA+/+ SCID mice with humanized livers (chimeric mice). This study presents the results of 19-norandrost-4-ene-3,17-dione (19-norAD) administration to these in vivo mice. As in humans, 19-norandrosterone and 19-noretiocholanolone are the major detectable metabolites of 19-norAD in the urine of chimeric mice. A summary is given of the metabolic pathways found in chimeric mice after administration of three model steroid compounds (methandienone, androst-4-ene-3,17-dione and 19-norandrost-4-ene-3,17-dione). From these studies we can conclude that all major metabolic pathways for anabolic steroids in humans are present in the chimeric mouse. It is hoped that, in future, this promising chimeric mouse model might assist the discovery of new and possible longer detectable metabolites of (designer) steroids. Copyright © 2009 John Wiley & Sons, Ltd.

The applicability of LC-MS/MS in precursor ion scan mode for the detection of urinary stanozolol metabolites has been studied. The product ion at m/z 81 has been selected as specific for stanozolol metabolites without a modification in A- or N-rings and the product ions at m/z 97 and 145 for the metabolites hydroxylated in the N-ring and 4-hydroxy-stanozolol metabolites, respectively. Under these conditions, the parent drug and up to 15 metabolites were found in a positive doping test sample. The study of a sample from a chimeric uPA-SCID mouse collected after the administration of stanozolol revealed the presence of 4 additional metabolites. The information obtained from the product ion spectra was used to develop a SRM method for the detection of 19 compounds. This SRM method was applied to several doping positive samples. All the metabolites were detected in both the uPA-SCID mouse sample and positive human samples and were not detected in none of the blank samples tested; confirming the metabolic nature of all the detected compounds. In addition, the application of the SRM method to a single human excretion study revealed that one of the metabolites (4ξ,16ξ-dihydroxy-stanozolol) could be detected in negative ionization mode for a longer period than those commonly used in the screening for stanozolol misuse (3′-hydroxy-stanozolol, 16β-hydroxy-stanozolol and 4β-hydroxy-stanozolol) in doping analysis. The application of the developed approach to several positive doping samples confirmed the usefulness of this metabolite for the screening of stanozolol misuse. Finally, a tentative structure for each detected metabolite has been proposed based on the product ion spectra measured with accurate masses using UPLC-QTOF MS. © 2009 Elsevier Inc. All rights reserved.

Background: Adequate detection of designer steroids in the urine of athletes is still a challenge in doping control analysis and requires knowledge of steroid metabolism. In this study we investigated whether uPA+/+-SCID mice carrying functional primary human hepatocytes in their liver would provide a suitable alternative small animal model for the investigation of human steroid metabolism in vivo. Methods: A quantitative method based on liquid chromatography–tandem mass spectrometry (LC-MS/MS) was developed and validated for the urinary detection of 7 known methandienone metabolites. Application of this method to urine samples from humanized mice after methandienone administration allowed for comparison with data from in vivo human samples and with reported methandienone data from in vitro hepatocyte cultures. Results: The LC-MS/MS method validation in mouse and human urine indicated good linearity, precision, and recovery. Using this method we quantified 6 of 7 known human methandienone metabolites in the urine of chimeric mice, whereas in control nonchimeric mice we detected only 2 metabolites. These results correlated very well with methandienone metabolism in humans. In addition, we detected 4 isomers of methandienone metabolites in both human and chimeric mouse urine. One of these isomers has never been reported before. Conclusions: The results of this proof-of-concept study indicate that the human liver–uPA+/+-SCID mouse appears to be a suitable small animal model for the investigation of human-type metabolism of anabolic steroids and possibly also for other types of drugs and medications. .

The misuse of the anabolic steroid methyltestosterone is currently routinely monitored in doping control laboratories by gas chromatography-mass spectrometry (GC-MS) of two of its metabolites: 17alpha-methyl-5beta-androstane-3alpha,17beta-diol and 17alpha-methyl-5alpha-androstane-3alpha,17beta-diol. Because of the absence of any easy ionizable moiety, these metabolites are poorly detectable using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). In this study, the metabolism of methyltestosterone has been reinvestigated by the use of a precursor ion scan method in LC-ESI-MS/MS. Two metabolites have been detected using this method. Both compounds have been confirmed in postadministration urine samples of an urokinase plasminogen activator-severe combined immunodeficiency (uPA-SCID) mouse with humanized liver and were characterized by LC-MS/MS and GC-MS using both quadrupole and time of flight analyzers. From the detailed study of the fragmentation, these metabolites were proposed to be epimethyltestosterone and a dehydrogenated compound. Epimethyltestosterone has previously been described as a minor metabolite, whereas the occurrence of the oxidized metabolite has not been reported. Comparison with the synthesized reference revealed that the structure of the dehydrogenated metabolite is 6-ene-epimethyltestosterone. A selected reaction monitoring method including three transitions for each metabolite has been developed and applied to samples from an excretion study and to samples declared positive after GC-MS analysis. 6-Ene-epimethyltestosterone was found in all samples, showing its applicability in the detection of methyltestosterone misuse.

Background: Universal and timely administration of a prepandemic vaccine is considered to be one of the most effective measures to reduce the incidence of pandemic influenza infection and consequently its morbidity and mortality. Objectives: To provide the reader with basic insights into influenza virus infections, the threat of a pandemic and the challenges it poses for vaccine development. Methods: This review summarizes the reported preclinical and clinical data obtained with the prepandemic H5N1 vaccine adjuvanted with AS03. Results: The AS03-adjuvanted prepandemic H5N1 influenza vaccine allows for antigen sparing, has a good safety and acceptable reactogenicity profile, induces an immune response that not only meets all European Committee for Medicinal Products (CHMP) and FDA requirements for the vaccine strain but also generates neutralizing antibodies that broadly cross-react against H5N1 drift strains, and finally conveys protection in a ferret model against lethal challenges with homologous and h...

In this observational study, mumps-specific in vitro lymphoproliferation was measured in 24 subjects with low antibody titers and 24 subjects with high antibody titers who received their last vaccine dose up to 16 years previously. Overall, a significant lymphoproliferative response was found in 32 subjects (66.7%)-namely, in 13 (54.2%) of those with low antibody titers and 19 (79.2%) of those with high antibody titers. The mean stimulation index for subjects with low antibody titers was 4.47, whereas that for subjects with high antibody titers was 8.31 (P=.032). Mumps vaccine-induced cell-mediated immunity appears to be more persistent than the antibody response.

Hepatitis B virus (HBV) infections cause 500,000 to 700,000 deaths per year as a consequence of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Efficient and safe antivirals to treat chronically infected patients and consequently to prevent development of hepatocellular carcinoma are still awaited. We isolated five single-domain antibodies (VHHs) that recognize the most abundant envelope protein (S) of HBV. VHHs, when expressed and retained in the endoplasmic reticulum as intrabodies, reduced levels of secreted hepatitis B surface antigen (HBsAg) particles in a cellular HBV model. In a hydrodynamics-based HBV mouse model, these intrabodies caused a marked reduction in HBsAg concentrations and a 10- to >100-fold reduction in the concentration of HBV virions in plasma. Conclusion: VHHs potently inhibited secretion of HBV virions in vivo, showing that this approach might be useful in the treatment of HBV. To our knowledge, this is the first report of intrabody-mediated inhibition of viral secretion in mammals. (HEPATOLOGY 2009;49:39-49.)

The study of the hepatitis B virus (HBV) and the hepatitis C virus (HCV) has long been hampered by the lack of a suitable small animal model. Both viruses could only be studied in humans or in chimpanzees. Recently, a new chimeric mouse model was developed that was permissive for HBV and HCV infection. In this model, uPA+/+-SCID mice, suffering from a transgene-induced liver disease, are transplanted early after birth with primary human hepatocytes. These human hepatocytes integrate in the parenchyma and progressively repopulate the diseased mouse liver without losing their normal metabolic functions. Successfully transplanted mice can then be infected with HBV and HCV. In this review, we describe the characteristics of this chimeric mouse model in more detail and give an overview of how this model has already contributed to the development of new antiviral compounds for the treatment of viral hepatitis.

Background. @nbsp; To protect a naive global population against pandemic influenza, pandemic vaccines should be effective at low antigen doses, because of limited manufacturing capacity. Methods. @nbsp; In a multicenter, randomized, blind-observer phase 1 trial, groups of 50 healthy young adults received 2 doses, 21 days apart, of influenza A/Vietnam/1194/2004 NIBRG-14 (H5N1) vaccine containing 1.9, 3.8, 7.5 or 15 mug of hemagglutinin with oil-in-water emulsion adjuvant or 7.5 mug of hemagglutinin without adjuvant. Safety was monitored to day 42. Homologous hemagglutination-inhibition (HI) and microneutralization titers were determined after each vaccination. Cross-reactivity against A/Indonesia/05/2005 RG2 was tested after the second vaccination. Results. @nbsp; No vaccine-related significant or serious adverse events occurred. Injection site reactions, but not systemic reactions, were more frequent with adjuvant than without. Even with only 1.9 mug of hemagglutinin plus adjuvant, 72% of subjects had HI titers >/=1:32 after 2 doses. This proportion was 81%-89% with higher adjuvanted doses but was only 34% without adjuvant. Adjuvanted vaccine induced cross-neutralizing antibodies in 39%-65% of samples, versus 7% without adjuvant. Conclusions. @nbsp; The emulsion-adjuvanted pandemic influenza vaccine candidate was safe, immunogenic, and induced cross-reactive antibodies. This adjuvanted 1.9-mug candidate is the lowest effective dose tested to date. This could have a major impact on prepandemic vaccination strategies with stockpiled batches of vaccine. Trial registration. @nbsp; ClinicalTrials.gov identifier: NCT00457509 .

A quantitative method based on gas chromatography–mass spectrometry (GC–MS) has been developed for the detection of 16 endogenous androgens in the urine of mice. The substances are extracted from 100 μL urine with freshly distilled diethyl ether after alkalinisation. The substances are derivatised with a mixture of N -methyl- N -trimethylsilyltrifluoroacetamide/NH 4 I/ethanethiol (383/1/2, v/w/v) and detected by GC–MS in the selected ion monitoring mode. The results of the method validation indicate good linearity, accuracy and precision, making the method suitable for the quantification of endogenous androgens in mouse urine. The selectivity of the method showed that no interfering peaks were observed at the retention times of the analytes. The method allows for the direct quantification and identification of testosterone and 15 other endogenous androgens at low concentrations (ng/mL) in mouse urine. The applicability of the method is shown by the analysis of a mouse urine. Several endogenous steroids could be detected.

Proven efficacy and safety of hepatitis B vaccines Hepatitis B virus (HBV) infection is a serious global health problem, with two billion people infected worldwide, and 350 million suffering from chronic HBV infection. HBV infections result in 500,000 to 1.2 million deaths per year caused by chronic hepatitis, cirrhosis, and hepatocellular 1-3 carcinoma; the latter accounts for 320,000 deaths per year. Less than 20 years after the discovery of the hepatitis B surface antigen (HBsAg) and the hepatitis B virus, a vaccine 4,5 against HBV was developed and licensed for use. This vaccine contained HBsAg that was purified from plasma taken from patients chronically infected with HBV. Impressively, only a few years later a vaccine was licensed that contained HBsAg that was produced in Saccharomyces cerevisiae. Since this first successful introduction of a recombinant vaccine to prevent an infectious disease, vaccines that contained HBsAg produced in Hansenula polymorpha, Pichia pastoris, and mammalian cells were developed. The use of these vaccines has reduced the occurence of hepatitis B infections in the targeted populations.

Induction of curative immune responses by therapeutic vaccination in chronic viral infections such as chronic hepatitis B (CHB) is expected to be facilitated by reduction of viral load by antiviral treatment. In this open label, controlled, randomized study, 195 patients with HBeAg positive CHB were randomized to receive 12 doses of HBsAg with AS02B adjuvant candidate vaccine plus lamivudine daily for 52 weeks or lamivudine daily alone. The combined administration of vaccine and lamivudine was safe and well tolerated, but did not improve the HBe seroconversion rate (18.8%) when compared to treatment with lamivudine alone (16.1%) (p=0.6824). Despite induction of a vigorous HBsAg-specific lymphoproliferative response, cytokine production and anti-HBs antibodies, therapeutic vaccination with an adjuvanted HBsAg vaccine administered concomitantly with lamivudine did not demonstrate superior clinical efficacy in HBeAg positive CHB patients as compared to lamivudine therapy alone.

Hepatitis C virus (HCV) infection of Huh-7.5 hepatoma cells results in focal areas of infection where transmission is potentiated by cell-cell contact. To define route(s) of transmission, HCV was allowed to infect hepatoma cells in the presence or absence of antibodies that neutralize cell-free virus infectivity. Neutralizing antibodies (nAbs) reduced cell-free virus infectivity by >95% and had minimal effect(s) on the frequency of infected cells in the culture. To assess whether cell-cell transfer of viral infectivity occurs, HCV-infected cells were cocultured with fluorescently labeled naive cells in the presence or absence of nAbs. Enumeration by flow cytometry demonstrated cell-cell transfer of infectivity in the presence or absence of nAbs and immunoglobulins from HCV+ patients. The host cell molecule CD81 and the tight junction protein Claudin 1 (CLDN1) are critical factors defining HCV entry. Soluble CD81 and anti-CD81 abrogated cell-free infection of Huh-7.5 and partially inhibited cell-cell transfer of infection. CD81-negative HepG2 hepatoma cells were resistant to cell-free virus infection but became infected after coculturing with JFH-infected cells in the presence of nAb, confirming that CD81-independent routes of cell-cell transmission exist. Further experiments with 293T and 293T-CLDN1 targets suggested that cell-cell transmission is dependent on CLDN1 expression. Conclusion: These data suggest that HCV can transmit in vitro by at least two routes, cell-free virus infection and direct transfer between cells, with the latter offering a novel route for evading nAbs. (HEPATOLOGY 2007.)

Background & Aims: Because current therapies for chronic hepatitis C virus (HCV) infections are suboptimal and associated with severe side effects, novel treatment options are needed. A small animal model has recently been developed to study HCV infections. To examine the usefulness of this human liver–urokinase-type plasminogen activator (uPA) +/+ severe combined immune deficient (SCID) mouse for the development of HCV-targeted drugs, we evaluated the antiviral efficacy and safety of an HCV NS3-protease inhibitor, BILN 2061. Methods: BILN 2061 was orally administered at clinical range doses for 4 days to SCID mice that differed in the presence of HCV infection, human hepatocyte grafts, and uPA zygosity. Treatment outcome was evaluated clinically, virologically, and morphologically. Using standard high-performance liquid chromatography–ultraviolet (HPLC-UV) methods and mass spectrometry, single-dose pharmacokinetics and multiple-dose drug exposures were analyzed. The 13 C-aminopyrine breath test was applied to compare in vivo liver function. Results: A 4-day treatment with BILN 2061 of HCV genotype-1b infected chimeric animals reduced the viral load by >100-fold, but concomitant clinical and ultrastructural signs of cardiotoxicity appeared. BILN 2061 administration to uPA-transgenic mice induced mitochondrial swelling with aberrant cristae in cardiomyocytes, but not in skeletal muscle. Because both drug accumulation and liver function were identical in affected uPA-transgenic and nontransgenic SCID mice without cardiac involvement, the urokinase plasminogen activator transgene itself appears to be implicated. Conclusions: The human liver-uPA +/+ SCID mouse is an interesting small animal model to evaluate the preclinical safety and efficacy of new antiviral compounds against HCV. The uPA-transgene increases the susceptibility of mice to BILN 2061-induced cardiotoxicity.

Summary Background Antigen sparing is regarded as crucial for pandemic vaccine development because worldwide influenza vaccine production capacity is limited. Adjuvantation is an important antigen-sparing strategy. We assessed the safety and immunogenicity of a recombinant H5N1 split-virion vaccine formulated with a proprietary adjuvant system and investigated whether it can induce cross-reactive immunity. Methods Two doses of an inactivated split A/Vietnam/1194/2004 NIBRG-14 (recombinant H5N1 engineered by reverse genetics) vaccine were administered 21 days apart to eight groups of 50 volunteers aged 18–60 years. We studied four antigen doses (3·8 μg, 7·5 μg, 15 μg, and 30 μg haemagglutinin) given with or without adjuvant. Blood samples were collected to analyse humoral immune response. Adverse events were recorded up through study day 51. Safety analyses were of the whole vaccinated cohort and immunogenicity analyses per protocol. This trial is registered with the ClinicalTrials.gov, number NCT00309634. Findings All eight vaccine formulations had a good safety profile. No serious adverse events were reported. The adjuvanted vaccines induced more injection-site symptoms and general symptoms than did the non-adjuvanted vaccines, but most were mild to moderate in intensity and transient in nature. The adjuvanted formulations were significantly more immunogenic than the non-adjuvanted formulations at all antigen doses. At the lowest antigenic dose (3·8 μg), immune responses for the adjuvanted vaccine against the recombinant homologous vaccine strain (A/Vietnam/1194/2004 NIBRG-14, clade 1) met or exceeded all US Food and Drug Administration and European Union licensure criteria. Furthermore, 37 of 48 (77%) participants receiving 3·8 μg of the adjuvanted vaccine seroconverted for neutralising antibodies against a strain derived by reverse genetics from a drifted H5N1 isolate (A/Indonesia/5/2005, clade 2). Interpretation Adjuvantation conferred significant antigen sparing that could increase the production capacity of pandemic influenza vaccine. Moreover, the cross-clade neutralising antibody responses recorded imply that such a vaccine could be deployed for immunisation before a pandemic.

The nucleocapsid or core particle of the hepatitis B virus has become one of the favourite recombinant vaccine carriers for foreign peptides, proteins and stimulatory oligonucleotides. The core protein consists of three regions: an N-terminal, a central and a C-terminal region that can accommodate the addition or insertion of the foreign sequences. The protamine-like C-terminal region that binds host RNA randomly during recombinant particle formation is often truncated. It is commonly thought that these truncations do not affect particle assembly. Recent studies have demonstrated that the C-terminal domains mediate a glycosaminoglycan-dependent attachment of nucleocapsids to the plasma membranes of host cells. This interaction might well contribute to the immunogenicity of nucleocapsids. Testing the hypothesis that full-length particles might be safer and superior for the induction of an immune response against the nucleocapsids and inserted sequences, requires the availability of purified particles. In this report, we detail a novel method for the synthesis and purification of full-length core particles essentially free of RNA from Escherichia coli.

Summary Background Hepatitis A and B infections are prevalent worldwide and cause significant morbidity and mortality. A combined vaccine providing dual protection against hepatitis A and B is available (Twinrix®, GlaxoSmithKline Biologicals). Method Two cohorts of adults aged 17–43 years were vaccinated with Twinrix® according to a 0, 1, 6 months schedule and followed up for 10 years. Results One month after the primary vaccination course (Month 7), all subjects were seropositive for anti-HAV and all had anti-HBs⩾10 mIU/ml. At month 120, 100% of subjects ( N =34; N =29) in both cohorts were seropositive for anti-HAV; 94.1% and 86.2% of subjects had anti-HBs⩾10 mIU/ml. The geometric mean concentrations (GMC; mIU/ml) were 373.9 and 674.6 in the two cohorts for anti-HAV, and 103.8 and 320.0, respectively, for anti-HBs. None of the serious adverse events reported throughout the follow-up period were considered by the investigator to be causally related to vaccination. Conclusions Combined hepatitis A and B vaccine, Twinrix®, is safe, well-tolerated and has demonstrated a highly immunogenic profile. Persistence of anti-HAV and anti-HBs antibodies in adults remains high for at least 10 years after primary vaccination.

The prevalence of markers for hepatitis B virus (HBV) exposure and active infection in HIV-positive (n = 710) and HIV-negative (n = 710) pregnant South African women was investigated. The following statistically significant increases in the HIV-positive group were found: anti-hepatitis B core antigen (anti-HBc) (37.3% versus 28.6%; odds ratio [OR]: 1.49); anti-hepatitis B surface antigen (anti-HBs) (29.5% versus 20.1%; OR: 1.66); exposure based on hepatitis B surface antigen (HBsAg) and anti-HBc (39.2% versus 30.1 %; OR: 1.49); and exposure based on anti-HBs, anti-HBc and HBsAg (37.1% versus 24.5%; OR: 1.82). However, there was no increase in active HBV infections, with 2.4% of the HIV positives and 2.2% of the HIV negatives being HBV DNA positive. Although the impact that HIV has had on the prevalence of HBV in this population group is not as pronounced as that found in areas of low endemicity (where up to seven-fold increases have been reported), there is a statistically significant increased exposure to HBV.

The intrasplenic injection of human peripheral blood mononuclear cells (PBMCs) into severely immune deficient NOD/SCID mice, causes a massive and transient dominant expansion of human B cells in the spleen. This permits the easy isolation of human monoclonal antibodies specific for different antigens by a Kohler and Milstein-based method. Here we studied the human HIV-specific antibody response in the circulation of mice after intrasplenic transfer of PBMC from untreated HIV-infected patients with detectable to high viral load as well as from HAART-treated and from untreated patients, who kept an undetectable viral load (the latter referred to as “natural suppressors”). Excellent B cell expansion was obtained for all PBMC. High level replication of virus was observed after transfer of PBMC of untreated viremic patients only. A strong and multispecific HIV-specific antibody response was observed after transfer of PBMC of untreated viremic patients and natural suppressors. In contrast, only a weak and pauci-specific antibody response was detected in mice reconstituted with PBMC from successfully treated patients. Based on these observations we conclude that the use of the intraspleen mouse model confirmed a) the presence of HIV-specific circulating memory B cells in untreated patients and natural suppressors; b) the nearly complete absence of circulating memory B cells in patients receiving highly active antiretroviral therapy. Using the intraspleen model we generated large numbers of immortalized B cells and isolated two anti-p24 human monoclonal antibodies. We further conclude that the intraspleen huPBL NOD/SCID model is a small animal model useful for the analysis of the antibody response against HIV found in patients.

In order to understand better the clinical significance and prognostic value of antibody responses to HCV proteins and in search for parameters that may allow the early identification of non-sustained responders to therapy, antibody levels were measured against NS3, NS4a and NS5a at baseline in the serum of 120 patients chronically infected with HCV of genotype 1 that were classified as sustained responders, relapsers, or non-responders to therapy. The capacity of these antibody tests to predict therapy-outcome was evaluated. While no differences were observed in the anti-NS3 responses in these different response groups, anti-NS4a and anti-NS5a antibodies were observed more frequently and at higher titres in sustained responders versus non-responders or non-sustained responders (=non-responders + relapsers). Based on this observation, a combination of test results consisting of 'the absence of NS4a (AA 1687-1718) antibody at baseline and the presence of HCV-RNA exceeding 105 IU/ml after 1 week of treatment' was identified which predicts non-sustained response to treatment with 100% certainty. Replacing the HCV-RNA decision limit by a HCV-core antigen level of >15 pg/ml resulted in the same predictive value. The proposed algorithm also holds for patients treated with peg-interferon and ribavirin. In conclusion, in patients with chronic HCV infection, the decision to continue or stop treatment can be made after 1 week of treatment with (peg)-interferon α and ribavirin. © 2007 Wiley-Liss, Inc.

Humanized mice with a chimeric liver are a promising tool to evaluate the "in vivo" efficacy of novel compounds or vaccine-induced antibodies directed against the pre-erythrocytic stages of Plasmodium falciparum. The absence of human red blood cells in these humanized mice precludes the transition from liver to blood stage. The qPCR-based method described below allows for a sensitive and reliable quantification of parasite DNA in the chimeric liver following a challenge via infected mosquito bite or intravenous injection of sporozoites. With this method approximately 25 % of the total chimeric liver is examined and a single infected hepatocyte can be detected in the analyzed tissue. The use of appropriate species-specific probes can also allow for the detection of other Plasmodium species in vivo.

The use of anabolic steroids is prohibited in sports. Effective control is done by monitoring their metabolites in urine samples collected from athletes. Ethical objections however restrict the use of designer steroids in human administration studies. To overcome these problems alternative in vitro and in vivo models were developed to identify metabolites and to assure a fast response by anti-doping laboratories to evolutions on the steroid market. In this study human liver microsomes and an uPA(+/+) -SCID chimeric mouse model were used to elucidate the metabolism of a steroid product called 'Xtreme DMZ'. This product contains the designer steroid dimethazine (DMZ), which consists of two methasterone molecules linked by an azine group. In the performed stability study, degradation from dimethazine to methasterone was observed. By a combination of LC-High Resolution Mass Spectrometry (HRMS) and GC-MS(/MS) analysis methasterone and six other dimethazine metabolites (M1-M6), which are all methasterone metabolites, could be detected besides the parent compound in both models. The phase II metabolism of dimethazine was also investigated in the mouse urine samples. Only metabolites M1 and M2 were exclusively detected in the glucuro-conjugated fraction; all other compounds were also found in the free fraction. For effective control of DMZ misuse in doping control samples, screening for methasterone and methasterone metabolites should be sufficient. Copyright © 2016 John WileySons, Ltd.

SCOPUS: le.j, info:eu-repo/semantics/published

Background. To investigate the relationship between hemagglutinin-inhibition (HI) antibody levels to the risk of influenza disease, we conducted a correlate of protection analysis using pooled data from previously published randomized trials. Methods. Data on the occurrence of laboratory-confirmed influenza and HI levels pre- and postvaccination were analyzed from 4 datasets: 3 datasets included subjects aged Results. The baseline odds ratio of A/H3N2 disease was higher for subjects aged ≥65 years than Conclusions. The modeling exercise confirmed a relationship between A/H3N2 disease and HI responses, but it did not allow an evaluation of the predictive power of the HI response.

Objectives Plasmodium falciparum sporozoites, deposited in the skin by infected Anopheles mosquitoes taking a blood meal, cross the endothelium of skin capillaries and travel to the liver where they traverse Kupffer cells and hepatocytes to finally invade a small number of the latter. In hepatocytes, sporozoites replicate, differentiate and give rise to large numbers of merozoites that are released into the bloodstream where they invade red blood cells, thus initiating the symptomatic blood stage. Using in vitro systems and rodent models, it has been shown that the hepatocyte receptors CD81 and scavenger receptor type B class I (SR-BI) play a pivotal role during sporozoite invasion. We wanted to evaluate whether these two entry factors are genuine drug targets for the prevention of P. falciparum infection in humans. Methods Immunodeficient mice of which the liver is largely repopulated by human hepatocytes were treated with monoclonal antibodies blocking either CD81 or SR-BI 1 day prior to challenge with infected mosquitoes. P. falciparum infection of the liver was demonstrated using a qPCR assay. Results In human liver chimeric mice, an antibody directed against CD81 completely blocked P. falciparum sporozoite invasion while SR-BI-specific monoclonal antibodies did not influence in vivo infection. Conclusions These observations confirm the role of CD81 in liver-stage malaria and question that of SR-BI. CD81 might be a valuable drug target for the prevention of malaria.

Humanized mice with a chimeric liver are a promising tool to evaluate the "in vivo" efficacy of novel compounds or vaccine-induced antibodies directed against the pre-erythrocytic stages of Plasmodium falciparum. The absence of human red blood cells in these humanized mice precludes the transition from liver to blood stage. The qPCR-based method described below allows for a sensitive and reliable quantification of parasite DNA in the chimeric liver following a challenge via infected mosquito bite or intravenous injection of sporozoites. With this method approximately 25 % of the total chimeric liver is examined and a single infected hepatocyte can be detected in the analyzed tissue. The use of appropriate species-specific probes can also allow for the detection of other Plasmodium species in vivo.

It is generally accepted that the host's immune response rather than the virus itself is causing the hepatocellular damage seen in acute and chronic hepatitis B virus (HBV) infections. However, in situations of severe immune suppression, chronic HBV patients may develop a considerable degree of liver disease. To examine whether HBV has direct cytopathic effects in severely immune compromised hosts, we have infected severe combined immune deficient mice (uPA-SCID), harboring human liver cells, with HBV. Serologic analysis of the plasma of HBV-infected animals revealed the presence of extremely high amounts of viral genomes and proteins. Histological analysis of the livers of uPA-SCID chimeras infected with HBV for more than 2 months showed that the majority of human hepatocytes had a ground-glass appearance, stained intensely for viral proteins, and showed signs of considerable damage and cell death. This histopathologic pattern closely resembles the picture observed in the livers of immunosuppressed HBV patients. These lesions were not observed in animals infected with HBV for less than 1 month. Ultrastructural analysis of long-term-infected hepatocytes showed a highly increased presence of cylindrical HBsAg structures, core particles, and Dane particles compared to short-term-infected hepatocytes. These long-term-infected hepatocytes also contained elevated amounts of HBV cccDNA. In conclusion, HBV causes dramatic intracellular changes and hepatocellular damage in the human hepatocytes that reside in a severely immune deficient mouse. These lesions show much resemblance to the ones encountered in immunosuppressed chronic HBV patients. Our observations indicate that HBV may be directly cytopathic in conditions of severe immune suppression.