Tuning the mass of chameleon fields in Casimir force experiments.

We have calculated the chameleon pressure between two parallel plates in the presence of an intervening medium that affects the mass of the chameleon field. As intuitively expected, the gas in the gap weakens the chameleon interaction mechanism with a screening effect that increases with the plate separation and with the density of the intervening medium. This phenomenon might open up new directions in the search of chameleon particles with future long-range Casimir force experiments.

Cosmology with massive neutrinos coupled to dark energy.

Cosmological consequences of a coupling between massive neutrinos and dark energy are investigated. In such models, the neutrino mass is a function of a scalar field, which plays the role of dark energy. The evolution of the background and cosmological perturbations are discussed. We find that mass-varying neutrinos can leave a significant imprint on the anisotropies in the cosmic microwave background and even lead to a reduction of power on large angular scales.

Drug interactions in the treatment of Parkinson's disease.

In recent years, the antiparkinsonian drug regime has become increasingly complicated. A wide range of antiparkinson agents is meanwhile available. Combination therapies may unfortunately induce interactions up to the point of life-threatening events. The potential of drug-drug interactions must be taken into account before starting a patient on combination treatment. Moreover, the frequent multimorbidity of patients with Parkinson's disease necessitates the application of additional drugs. A general overview is difficult to maintain because of the countless number of possible interactions. Cautious proceeding is certainly indicated in particular cases. The most common interactions will be discussed below. We should bear in mind that many of the interactions related to drug combinations are unknown yet.

Recombinant human papillomavirus type 16 E7 protein as a model antigen to study the vaccine potential in control and E7 transgenic mice.

The early genes E6 and E7 of human papillomavirus type 16 (HPV16) are consistently and exclusively expressed in HPV16-induced cancer lesions and play major roles in the development and maintenance of the malignant phenotype. Because this protein is a good example of a tumor-associated antigen, we have used E7 as a model antigen to test the potential of an experimental vaccine as an immunotherapeutic approach. In this study, we used a murine E7-expressing tumor model (TC1 cells) to assess effects of an E7-based vaccine on tumor growth. We show that vaccination with the E7 protein, formulated in the SmithKline Beecham Biologicals proprietary adjuvants (SBAS 1 and SBAS 2), leads to the rejection of pre-established tumors. Tumor rejection was associated with the induction of a strong systemic T helper 1 response, including CTLs, and the presence of an inflammatory infiltrate within the regressing tumor. Because most identified tumor-associated antigens are self antigens rather viral antigens, we used E7 transgenic mice to evaluate the E7-based vaccine in conditions where E7 is a self antigen. Transgenic mice, which constitutively and specifically express the E7 HPV16 gene in the thyroid epithelium, rapidly develop thyroid goiters and, after several months, thyroid carcinomas. We show that E7-specific antibodies and CD4 T helper responses can be obtained by vaccinating E7 transgenic mice, although a CTL response was not detected. Despite the absence of measurable CTL responses, vaccination still reduced the growth of pre-established TC1 tumors, although less efficiently than in nontransgenic animals, but was unable to suppress or delay the development of the spontaneous thyroid pathology.

Therapeutic potential of protein and adjuvant vaccinations on tumour growth.

Over 90% of cervical cancers are associated with HPV infection, the commonest being the HPV-16 subtype. Two early viral genes, E6 and 7, play major roles in the development and maintenance of the malignant phenotype. The vaccine potential of a recombinant HPV16 E7 protein was examined in two murine models of E7-expressing tumours. Formulations including the immunostimulants MPL and QS21 induced therapeutically active immune responses leading to regression of pre-established TC1 tumour lesions, associated with induction of IgG antibodies, lymphoproliferation and CTL. Our data provide a clear incentive to investigate the clinical application of this approach in cancer immunotherapy.

The adjuvant monophosphoryl lipid A increases the function of antigen-presenting cells.

The induction of immune responses in vivo is typically performed with antigens administered in external adjuvants, like alum, complete Freund's adjuvant, LPS and, more recently, monophosphoryl lipid A (MPL). However, the role of the adjuvant is still poorly defined. The aim of this study was to test whether the MPL affects the function of antigen-presenting cells (APC) in vitro and in vivo. Antigen-pulsed APC [including macrophages, B cells and dendritic cells (DC)] were incubated or not with MPL, and their ability to sensitize naive T cells was tested in vitro and in vivo. The data show that MPL enhances the ability of macrophages and B cells to sensitize naive T cells, and confers to them the capacity to induce the development of T(h)1 and T(h)2. Administration of MPL i.v. in mice results in the redistribution of fully mature DC in the T cell area of the spleen. These observations suggest that MPL may induce an antigen-specific primary immune response by provoking the migration and maturation of DC that are the physiological adjuvant of the immune system.

Consequences associated with work-to-family conflict: a review and agenda for future research.

A comprehensive review of the outcomes associated with work-to-family conflict was conducted and effect sizes were estimated. Atypology was presented that grouped outcomes into 3 categories: work related, nonwork related, and stress related. Issues concerning the measurement of work-family conflict were also discussed. The results demonstrate the widespread and serious consequences associated with work-to-family conflict. On the basis of the results of the review, an agenda for future research was provided.

A phase I trial in HIV negative healthy volunteers evaluating the effect of potent adjuvants on immunogenicity of a recombinant gp120W61D derived from dual tropic R5X4 HIV-1ACH320.

Thirty healthy HIV negative volunteers were randomised to receive 200 micrograms of rgp120W61D in either: 3D-MPL and QS21, with an oil and water emulsion (SBAS-2) (13); or 3D-MPL and QS21 (SBAS-1) (11); or alum (six). Immunizations were given at 0, 4 and 28 weeks and 23 (77%) participants completed the schedule. Adverse events were more frequent (P < 0.001) and more severe (P < 0.001) in the SBAS-2 group. Binding antibodies to the homologous rgp120W61D were detected after the first immunisation only in those receiving SBAS-1 and SBAS-2, were maximal after the third immunization in all three groups, and persisted to week 84 only in the novel adjuvant groups. These differences were significant (p = 0.02). Neutralising antibodies to TCLA-strains of HIV-1 were observed after the second immunization in all three groups, were maximal after the third immunization, but did not neutralise homologous or heterologous PBMC derived primary HIV-1 isolates. Proliferative T-cell responses to rgp120W61D were maximal after the second immunization and reached very high values in the SBAS-2 group. HIV-1 specific CD8+ MHC Class I restricted cytotoxic T-lymphocytes were not seen in a subset of participants tested at a single timepoint. SBAS-2 with rgp120W61D induced antibody titres as high as those seen in HIV infection, but the quality of the antibodies remained different in that there was no evidence of primary isolate neutralisation. Although cell-mediated immunity was enhanced by SBAS-2 in terms of lymphoproliferative responses, HIV-1 specific CD8+ cytotoxicity was not demonstrated.

Comparison of the antibody repertoire generated in healthy volunteers following immunization with a monomeric recombinant gp120 construct derived from a CCR5/CXCR4-using human immunodeficiency virus type 1 isolate with sera from naturally infected individuals.

We have characterized sera from healthy volunteers immunized with a monomeric recombinant gp120 (rgp120) derived from a CCR5/CXCR4 (R5X4)-using subtype B isolate of human immunodeficiency virus type (HIV-1), HIV-1W61D, in comparison to sera from long-term HIV-1-infected individuals, using homologous reagents. Sera from vaccinees and HIV-1 positive subjects had similar binding titers to native monomeric rgp120W61D and showed a similar titer of antibodies inhibiting the binding of soluble CD4 (sCD4) to rgp120W61D. However, extensive peptide binding studies showed that the overall pattern of recognition of vaccinee and HIV-1-positive sera is different, with vaccinee sera displaying a wider and more potent recognition of linear V1/V2 and V3 domain epitopes. Neutralization of homologous HIV-1W61D or heterologous HIV-1M2424/4 peripheral blood mononuclear cell (PBMC)-derived virus lines by vaccinee sera could be achieved, but only after adaptation of the viruses to T-cell lines and was quickly lost on readaptation to growth in PBMC. Sera from HIV-positive individuals were able to neutralize both PBMC-grown and T-cell line-adapted viruses. Interestingly, rgp120W61D was recognized by monoclonal antibodies previously shown to neutralize primary HIV-1 isolates. The use of very potent adjuvants and R5X4 rgp120 led to an antibody response equivalent in binding activity and inhibition of binding of sCD4 to gp120 to that of HIV-positive individuals but did not lead to the induction of antibodies capable of neutralizing PBMC-grown virus.

A clinically relevant HIV-1 subunit vaccine protects rhesus macaques from in vivo passaged simian-human immunodeficiency virus infection.

OBJECTIVES: To investigate whether immunization with recombinant HIV-1 envelope protein derived from a clinical isolate could protect macaques from infection with an in vivo passaged chimeric simian-human immunodeficiency virus (SHIV). DESIGN AND METHODS: A total of 16 animals were studied from which three groups of four animals were immunized with vaccine formulations of the CC-chemokine receptor-5-binding recombinant gp120 of HIV-1W6.1D. Four weeks after the last immunization, all 16 animals were intravenously challenged with in vivo passaged SHIV derived from the same HIV-1 group B clinical isolate (W6.1D) as the vaccines. RESULTS: Vaccine protection from infection was demonstrated in 10 out of 12 macaques immunized with recombinant gp120. Complete protection from infection was achieved with all of the animals that received the SBAS2-W6.1D formulation, a potent inducer of both T-cell and humoral immune responses. Partial protection was achieved with SBAS1-W6.1D, a formulation based on immunomodulators known to induce T-cell responses in humans. In vaccinated animals that were infected, virus load was reduced and infection was delayed. CONCLUSIONS: In a relatively large number of primates, vaccine efficacy was demonstrated with a clinically relevant HIV-1 vaccine. These results reveal that it is possible to induce sterilizing immunity sufficient to protect from infection with SHIV which was passaged multiple times in vivo. Our findings have implications for current HIV-1 clinical vaccine trials and ongoing efforts to develop safe prophylactic AIDS vaccines.

Evaluation of a candidate human immunodeficiency virus type 1 (HIV-1) vaccine in macaques: effect of vaccination with HIV-1 gp120 on subsequent challenge with heterologous simian immunodeficiency virus-HIV-1 chimeric virus.

Human immunodeficiency virus type 1 (HIV-1) envelope vaccines can now be evaluated for efficacy in macaques by challenging with chimeric viruses in which the env, tat and rev genes of simian immunodeficiency virus (SIV) have been replaced by those of HIV-1. Most experiments have so far been conducted using gp120 molecules derived from T-cell-adapted LAI or MN strains of HIV-1, which predominantly use the CXCR-4 co-receptor. These vaccines protect against infection by apathogenic chimeric virus carrying the same envelope sequences. In the experiment described here, four macaques were vaccinated with W61D gp120 derived from a low passage Dutch isolate and capable of inhibiting the binding of MIP1beta to the co-receptor CCR-5. This vaccine was potent, inducing high titres of binding and neutralizing antibodies against the homologous HIV-1 and tenfold lower titres against a heterologous challenge virus (SHIV(SF33)) in which the env, tat and rev genes of SIV had been replaced by those of a San Francisco isolate, HIV-1(SF33). Despite strong immune responses to the vaccine there was no evidence that it protected against challenge with this chimeric virus. The antigenic divergence between vaccine and challenge virus or the increased virulence of the challenge virus may be responsible for the inability of this vaccine to protect against infection by SHIV(SF33).

Neutralizing antibody responses induced by varicella-zoster virus gE and gB glycoproteins following infection, reactivation or immunization.

The purpose of this study was to compare the antibody responses to varicella-zoster virus (VZV) gE and gB after natural VZV infection and after vaccination with live attenuated OKA vaccine in order to determine the relative importance of these proteins as components of a subunit vaccine. Anti-VZV antibody titers determined by IFA were of the same order of magnitude in sera from individuals with a history of varicella and in vaccinated children but higher in individuals given booster vaccination. The titers of anti-gE and anti-gB antibodies were measured by ELISA using recombinant gE or gB as capture antigen. From these experiments, it appears that the ratio of anti-gE to anti-gB antibody is highly variable from one individual to another but relatively stable over a long period of time for a particular individual, even after a zoster episode. Neutralizing antibodies directed against gE or gB were also measured by subtracting the neutralization titers obtained before and after depletion of the specific antibodies on immobilized recombinant gE, gB, or both. This showed that, with respect to neutralization, anti-gE and anti-gB are equally prevalent in vaccinated children and that anti-gE is generally, but not always, predominant over anti-gB in VZV-infected individuals. Finally, antibodies to these two glycoproteins appear to be predominant among the neutralizing antibodies directed to other VZV antigens.

Protection against lethal simian immunodeficiency virus SIVsmmPBj14 disease by a recombinant Semliki Forest virus gp160 vaccine and by a gp120 subunit vaccine.

Infection of pigtail macaques with SIVsmmPBj14, biological clone 3 (SIV-PBj14-bc13), produces an acute and usually fatal shock-like syndrome 7 to 14 days after infection. We used this simian immunodeficiency virus (SIV) model as a rapid and rigorous challenge to evaluate the efficacy of two SIV Env vaccine strategies. Groups of four pigtail macaques were immunized four times over a 25-week span with either a recombinant Semliki Forest virus expressing the SIV-PBj14 Env gp160 (SFV-SIVgp160) or purified recombinant SIV-PBj14 gp120 (rgp120) in SBN-1 adjuvant. Antibody titers to SIV Env developed in all immunized animals (mean peak titers prior to challenge, 1:1,700 for SFV-SIV gp 160 and 1:10,500 for rgp120), but neither neutralizing antibodies nor SIV-specific T-cell proliferative responses were detectable in any of the vaccinees. All macaques were challenged with a 100% infectious, 75% fatal dose of SIV-PBj14-bc13 at week 26. Three of four control animals died of acute SIV-PBj14 syndrome on days 12 and 13. By contrast, all four SFV-SIVgp160-immunized animals and three of the four rgp120-immunized animals were protected from lethal disease. While all virus-challenged animals became infected, symptoms of the SIV-PBj14 syndrome were more severe in controls than in vaccinees. Mean virus titers in plasma at 13 days postchallenge were approximately 10-fold lower in vaccinated than control animals. However, there was no apparent correlation between survival and levels of peripheral blood mononuclear cell-associated culturable virus, provirus load, or any antiviral immunologic parameter examined. The results indicate that while immunization with SFV-SIVgp160 and rgp120 did not protect against virus infection, these Env vaccines did lower the virus load in plasma and protect against the lethal SIV-PBj14 challenge.

Simple enzyme immunoassay for titration of antibodies to the CD4-binding site of human immunodeficiency virus type 1 gp120.

We report the development of an immunoassay for the titration of antibody to the CD4-binding site (CD4BS) of the human immunodeficiency virus type 1 (HIV-1) surface glycoprotein gp120. This assay is a competitive enzyme-linked immunosorbent assay in which serum antibodies compete with labeled F105, a human monoclonal antibody whose corresponding epitope overlaps the conformation-dependent CD4BS, for binding to purified recombinant gp120 coated on a solid phase. Ninety-nine percent (109 of 110) of HIV-1-positive French patients and 91% (51 of 56) of HIV-1-positive African patients had CD4BS antibodies, indicating that the conformational CD4BS epitope is well conserved among different subtypes of HIV-1. Titers of CD4BS antibodies according to clinical status appeared to be not statistically different. A longitudinal study in 21 seroconverters showed that, for the majority of individuals, CD4BS antibodies appeared early and persisted at relatively high titers for several years. None of 21 HIV-2-seropositive patients had CD4BS antibodies in our assay, suggesting that the antibodies produced during HIV-2 infection are not cross-reactive with the CD4BS of HIV-1 gp120.

Virus load in chimpanzees infected with human immunodeficiency virus type 1: effect of pre-exposure vaccination.

Many reports indicate that a long-term asymptomatic state following human immunodeficiency virus type 1 (HIV-1) infection is associated with a low amount of circulating virus. To evaluate the possible effect of stabilizing a low virus load by non-sterilizing pre-exposure vaccination, a quantitative virus isolation method was developed and evaluated in four chronically infected chimpanzees infected with a variety of HIV-1 related isolates. This assay was then used to monitor a group of chimpanzees (n = 6) challenged with HIV-1 following vaccination with gp120 or gp160. Data indicated that of the three vaccinated animals which became infected after challenge, the animal with the lowest neutralizing titre at the time of challenge acquired a virus load similar to the control animals, whereas the two other chimpanzees had reduced numbers of virus producing cells in their peripheral circulation. One animal became virus isolation negative, developed an indeterminant PCR signal on lymph node DNA and subsequently became negative for HIV-1 DNA as determined by PCR on PBMC (peripheral blood mononuclear cells) and bone marrow DNA. Recently, the second animal has also become PCR negative. To confirm observations from quantitative virus isolations, quantification of HIV-1 DNA in PBMC and virus RNA in serum was performed by PCR on serially diluted samples at two different time points. Comparison of virus load as determined by these three methods confirmed that there was an effect of vaccination in reducing virus load and demonstrated a correlation between decreased numbers of virus producing cells, HIV-1 DNA containing cells and virus RNA molecules in serum.

Fine analysis of humoral antibody response to envelope glycoprotein of SIV in infected and vaccinated macaques.

To characterize the serological response to SIV envelope, induced by vaccination with different envelope immunogens or by SIV infection, plasma samples from 11 cynomolgus macaques infected with simian immunodeficiency virus (SIV) and from 16 macaques vaccinated with three different recombinant envelope proteins were analyzed by (1) ELISA, using a variety of antigens including overlapping peptides encompassing the entire sequence of the envelope protein of SIV, and (2) competition assays, using neutralizing monoclonal antibodies to SIV gp120. Seven regions of SIV envelope were predicted to be antigenic. Peptides representing four of these, in the second and third variable regions (V2 and V3) and the fourth constant (C4) region of gp120 and the Gnann region of gp41, were recognized by the majority of sera from infected and vaccinated animals. Additional antigenic regions were identified in the first and fourth variable domains (V1 and V4) and the carboxy terminus (C5) of gp120 and in three additional regions of gp41. Most infected and vaccinated animals made antibodies that competed with the binding of the three conformational MAbs. Among the vaccinated groups, antibodies induced by vaccination with precursor glycoproteins (gp140 or gp160) recognized several additional gp120 epitopes when compared with antibodies induced by external glycoprotein gp130. Sera from infected animals showed a more restricted gp120 response (17 of 46 peptides recognized) compared to animals vaccinated with precursor glycoproteins (31 peptides recognized). The converse was true for antibodies to gp41. Sera from animals vaccinated with recombinant gp140, produced in insect cells, were the only group that failed to compete with the binding of conformational MAbs. Finally, the development of antibodies to specific epitopes of gp120 and gp41 revealed differences between long-term survivors and nonsurvivors, implying that responses to specific epitopes may be important in conferring resistance to disease progression.

HIV-1 envelope-elicited neutralizing antibody titres correlate with protection and virus load in chimpanzees.

In an attempt to compare the protective effect of vaccination with two forms of envelope antigens, and to define immunological correlates of protection against HIV infection, chimpanzees were vaccinated with either recombinant gp160 or gp120. Homologous HIV challenge was performed 3 weeks after the fourth immunization. The animal with the highest level of serum neutralizing antibodies (gp160 immunogen) was protected against HIV infection. All other chimpanzees became infected, but displayed various levels of infected PBMCs. The postchallenge data gave rise to the following conclusions: (1) protection correlated with the level of the serological immune response, but not with the nature of immunogen (gp120 versus gp160); (2) the virus-neutralizing titre at day of challenge correlated with protection from infection; (3) the relative magnitude of the lymphoproliferative T-cell response at day of challenge did not correlate with any protective effect; (4) the peak numbers of virus-infected PBMCs in vaccinated animals were lower than those observed in control animals, and this effect was correlated with the intensity of the antibody response at day of challenge. This raises the possibility that a beneficial effect of HIV vaccination may be achieved in a situation where sterile immunity is not consistently obtained.