Papillomavirus virus-like particles for the delivery of multiple cytotoxic T cell epitopes

Chimeric papillomavirus (PV) virus-like particles (VLPs) based on the bovine papillomavirus type 1 (BPV-1) L1 protein were constructed by replacing the 23-carboxyl-terminal amino acids of the BPV1 major protein L1 with an artificial polytope minigene, containing known CTL epitopes of human PV16 E7 protein, HIV IIIB gp120 P18, Nef, and reverse transcriptase (RT) proteins, and an HPV16 E7 linear B epitope. The CTL epitopes were restricted by three different MHC class 1 alleles (H-2(b), H-2(d), HLA-A*0201). The chimeric L1 protein assembled into VLPs when expressed in SF-9 cells by recombinant baculovirus. After immunization of mice with polytope VLPs in the absence of adjuvant, serum antibodies were detected which reacted with both polytope VLPs and wild-type BPV1L1 VLPs, in addition to the HPV16E7 linear B cell epitope. CTL precursors specific for the HPV16 E7, HIV P18, and RT CTL epitopes were also detected in the spleen of immunized mice. Polytope VLPs can thus deliver multiple B and T epitopes as immunogens to the MHC class I and class II pathways, extending the utility of VLPs as self-adjuvanting immunogen delivery systems. (C) 2000 Academic Press.

Differences in the post-translational modifications of human papillomavirus type 6b major capsid protein expressed from a baculovirus system compared with a vaccinia virus system

Virus-like particles (VLPs) are being currently investigated in vaccines against viral infections in humans. There are different recombinant-protein-expression systems available for obtaining the necessary VLP preparation for vaccination. However, the differences in post-translational modifications of the recombinant proteins obtained and their differences in efficacy in eliciting an anti-viral response in vaccines are not well established. In this study we have compared the posttranslational modifications of human papillomavirus type-6b major capsid protein L1 (HPV 6bL1) expressed using recombinant baculovirus (rBV) in Sf9 (Spodoptera frugiperda) insect cells, with the protein expressed using recombinant vaccinia virus (rVV) in CV-1 kidney epithelial cells, Two-dimensional gel electrophoresis of biosynthetically labelled rBV-expressed HPV 6bL1 showed several post-translationally modified variants of the protein, whereas rVV-expressed HPV 6bL1 showed only a few variants. Phosphorylations were detected at threonine and serine residues for the L1 expressed from rBV compared with phosphorylation at serine residues only for the L1 expressed from rVV. HPV 6bL1 expressed using rBV incorporated [H-3]mannose and [H-3]galactose, whereas HPV 6bL1 expressed using rVV incorporated only [H-3]galactose. We conclude that post-translational modification of recombinant HPV 6bL1 can differ according to the system used for its expression. Since recombinant L1 protein is a potential human-vaccine candidate, the implication of the observed differences in post-translational modifications on immunogenicity of L1 VLPs warrants investigation.

Spectral tuning and the visual ecology of mantis shrimps

The compound eyes of mantis shrimps (stomatopod crustaceans) include an unparalleled diversity of visual pigments and spectral receptor classes in retinas of each species. We compared the visual pigment and spectral receptor classes of 12 species of gonodactyloid stomatopods from a variety of photo environments, from intertidal to deep water ( > 50 m), to learn how spectral tuning in the different photoreceptor types is modified within different photic environments. Results show that receptors of the peripheral photoreceptors, those outside the midband which are responsible for standard visual tasks such as spatial vision and motion detection, reveal the well-known pattern of decreasing lambda(max) with increasing depth. Receptors of midband rows 5 and 6, which are specialized for polarization vision, are similar in all species, having visual lambda(max)-values near 500 nm, independent of depth. Finally the spectral receptors of midband rows 1 to 4 are tuned for maximum coverage of the spectrum of irradiance available in the habitat of each species. The quality of the visual worlds experienced by each species we studied must vary considerably, but all appear to exploit the full capabilities offered by their complex visual systems.

Multiple conformational epitopes are recognized by natural and induced immunity to the E7 protein of human papilloma virus type 16 in man

The reactivity of sera from patients with cervical cancer with the E7 protein of human papilloma virus type 16 (HPV16) was estimated using a novel non-radioactive immunoprecipitation assay and four established protein-and peptide-based immunoassays. Six of 14 sera from patients with cervical cancer and 1 of 10 sera from healthy laboratory staff showed repeated reactivity with E7 in at least one assay. Four of the 7 reactive sera were consistently reactive in more than one assay, but only one was reactive in all four assays. Following immunization with E7, 2 of 5 patients with cervical cancer had increased E7-specific reactivity, measurable in one or more assays. No single assay was particularly sensitive for E7 reactivity, or predictive of cervical cancer. Mapping of E7 reactivity to specific E7 peptides was unsuccessful, suggesting that natural or induced E7 reactivity in human serum is commonly directed to conformational epitopes of E7, These results suggest that each assay employed with is study measures a different aspect of E7 reactivity, and that various reactivities to E7 may manifest following HPV infection or immunization. This finding is of significance for monitoring of E7 immunotherapy and for serological screening for cervical cancer. Copyright (C) 2000 S.Karger, AG. Basel.

Determination of activation energy distributions for chemisorption of oxygen on carbon: an improved approach

The present paper proposes an approach to obtaining the activation energy distribution for chemisorption of oxygen onto carbon surfaces, while simultaneously allowing for the activation energy dependence of the pre-exponential factor of the rate constant. Prior studies in this area have considered this factor to be uniform, thereby biasing estimated distributions. The results show that the derived activation energy distribution is not sensitive to the chemisorption mechanism because of the step function like property of the coverage. The activation energy distribution is essentially uniform for some carbons, and has two or possibly more discrete stages, suggestive of at least two types of sites, each with its own uniform distribution. The pre-exponential factors of the reactions are determined directly from the experimental data, and are found not to be constant as assumed in earlier work, but correlated with the activation energy. The latter results empirically follow an exponential function, supporting some earlier statistical and experimental work. The activation energy distribution obtained in the present paper permits improved correlation of chemisorption data in comparison to earlier studies. (C) 2000 Elsevier Science Ltd. All rights reserved.

Review of "Comorbidity, disability and the need for treatment for DSM-IV psychiatric disorders in an insured population"

Background: This study presents estimates of 12 month and current prevalences of DSM-IV disorders, and the related comor-bidity, disability and service utilization, derived from a national probability sample in Australia. Methods: The DSM-IV psychiatric disorders among persons aged 18 and over in the Australian population were assessed with data collected by lay interviewers using the Composite International Diagnostic Interview, other screening interviews and measures of disability and service utilization. The response rate was 78.1% and the final sample size was 10,641 adults. Results: Close to 20% reported at least one twelve month disorder and 13% a disorder current within the past 30 days. ICD-10 diagnoses were also derived, DSM-IV was the more conservative classification whether or not the new clinical significance criteria was applied. Major depression, any personality disorder, and alcohol dependence were the three most common twelve month disorders, generalized anxiety disorder replaced alcohol dependence as the third most common current disorder. The sexes has similar rates of any disorder, but women had higher rates of affective and anxiety disorders, men higher rates of substance use disorders. Prevalence of most disorders declined with age and education, and were lower among those employed or married. Respondents whose symptoms met criteria for three or more disorders in the past year had greatly increased rates of disability and of mental health consultations. The affective and somatoform disorders were associated with the highest rates of disability. Only 36% of people with a mental disorder this year had consulted for a mental problem, and most had seen a general practitioner. We identified those with a current disorder who were disabled or multiply comorbid - only half had consulted and of those who had not, more than half said they did not need treatment. Conclusions: The 12 month prevalence was lower than reported in the US National Comorbidity Survey but method factors might account for this. The relationships between prevalence and demographic variables, and between comorbidity, disability and service utilization were similar to those found in the US survey. Australia has a national health insurance scheme with total coverage and access to medical help is available to all, commonly at little or no cost. We identify the high rate of not consulting among those with a current disorder, and additional disability or multiple comorbidity, as an important public health problem. Kessler argued for more research on barriers to professional help seeking. This report reinforces his conclusion and shows that economic barriers are not the dominant issue.

Effect of removing user fees on attendance for curative and preventive primary health care services in rural South Africa

User fees are used to recover costs and discourage unnecessary attendance at primary care clinics in many developing countries. In South Africa, user fees for children aged under 6 yea rs and pregnant women were removed in 1994, and in 1997 all user fees at all primary health care clinics were abolished. The intention of these policy changes was to improve access to health services for previously disadvantaged communities. We investigated the impact of these changes on clinic attendance patterns in Hlabisa health district. Average quarterly new registrations and total attendances for preventive services (antenatal care, immunization, growth monitoring) and curative services (treatment of ailments) at a mobile primary health care unit were studied from 1992 to 1998. Regression analysis was undertaken to assess whether trends were statistically significant. There was a sustained increase in new registrations (P = 0.0001) and total attendances (P = 0.0001)for curative services, and a fall in new registrations (P = 0.01) and total attendances for immunization and growth monitoring (P = 0.0002) over the study period. The upturn in demand for curative services started at the time of the first policy change. The decreases in antenatal registrations (P = 0.07) and attendances (P = 0.09) were not statistically significant The number of new registrations for immunization and growth monitoring increased following the first policy change but declined thereafter. We found no evidence that the second policy change influenced underlying trends. The removal of user fees improved access to curative services but this may have happened at the expense of some preventive services. Governments should remain vigilant about the effects of new health policies in order to ensure that objectives are being met.

CD40 ligation conditions dendritic cell antigen-presenting function through sustained activation of NF-kappa B

An understanding of the biochemical control of dendritic cell (DC) differentiation/activation is essential for improving T cell immunity by various immunotherapeutic approaches, including DC immunization. Ligation of CD40 enhances DC function, including conditioning for CTL priming. NF-kappaB, and particularly RelB, is an essential control pathway for myeloid DC differentiation. Furthermore, RelB regulates B cell Ag-presenting function. We hypothesized that CD40 ligand (CD40L) and TNF-alpha, which differ in their capacity to condition DC, would also differ in their capacity to activate NF-kappaB. DC differentiated for 2 days from monocytes in the presence of GM-CSF and IL-4 were used as a model, as NF-kappaB activity was constitutively low. The capacity of DC to activate T cells following CD40L treatment was enhanced compared with TNF-alpha treatment, and this was NF-kappaB dependent. Whereas RelB/p50 translocation induced by TNF-alpha was attenuated after 6 h, RelB/p50 nuclear translocation induced by CD40L was sustained for at least 24 h. The mechanism of this difference related to enhanced degradation of IkappaBalpha following CD40L stimulation. However, NF-kappaB activation induced by TNF-alpha could be sustained by blocking autocrine IL-10. These data indicate that NF-kappaB activation is essential for T cell activation by DC, and that this function is enhanced if DC NF-kappaB activation is prolonged. Because IL-10 moderates DC NF-kappaB activation by TNF-alpha, sustained NF-kappaB activation can be achieved by blocking IL-10 in the presence of stimuli that induce TNF-alpha.

Allergen databases

Allergies represent a significant medical and industrial problem. Molecular and clinical data on allergens are growing exponentially and in this article we have reviewed nine specialized allergen databases and identified data sources related to protein allergens contained in general purpose molecular databases. An analysis of allergens contained in public databases indicates a high level of redundancy of entries and a relatively low coverage of allergens by individual databases. From this analysis we identify current database needs for allergy research and, in particular, highlight the need for a centralized reference allergen database.

A comparison of the performance and biological efficiency of new knapsack sprayers and a controlled droplet application (CDA) sprayer for the control of the diamondback moth, Plutella xylostella L. (Lepidoptera : Plutellidae)

Field trials and laboratory bioassays were undertaken to compare the performance and efficacy (mortality of diamondback moth larvae) of insecticides applied to cabbages with three high volume hydraulic knapsack sprayers (NS-16, PB-20 and Selecta 12V) and a controlled droplet application (CDA) sprayer. In field experiments, the high volume knapsack sprayers (application rate 500-600 L ha(-1)) provided better spray coverage on the upper and lower surfaces of inner leaves, the upper surfaces of middle and outer leaves, and greater biological efficacy than the CDA sprayer (application rate 20similar to40 L ha(-1)). The PB-20 provided better spray coverage on the upper surface of middle leaves and both surfaces of outer leaves when compared with the Selecta 12V. However, its biological efficacy in the field was not significantly different from that of the other high volume sprayers. Increasing the application rate from 20 to 40 L ha(-1) for the CDA sprayer significantly increased droplet density but had no impact on test insect mortality. Laboratory evaluations of biological efficacy yielded higher estimates than field evaluations and there was no significant difference between the performance of the PB-20 and the CDA sprayer. Significant positive relationships were detected between insect mortality and droplet density deposited for both the PB-20 and the CDA sprayers.

Achieving the millennium development goals for health - Cost effectiveness analysis of strategies for. maternal and neonatal health in developing countries

Objective To determine the costs and benefits of interventions for maternal and newborn health to assess the appropriateness of current strategies and guide future plans to attain the millennium development goals. Design Cost effectiveness analysis. Setting Two regions classified by the World Health Organization according to their epidemiological grouping: Afr-E, those countries in sub-Saharan Africa with very high adult and high child mortality, and Sear-D, comprising countries in South East Asia with high adult and high child mortality. Data sources Effectiveness data from several sources, including trials, observational studies, and expert opinion. For resource inputs, quantifies came from WHO guidelines, literature, and expert opinion, and prices from the WHO choosing interventions that are cost effective database. Main outcome measures Cost per disability adjusted life year (DALY) averted in year 2000 international dollars. Results The most cost effective mix of interventions was similar in Afr-E and Sear-D. These were the community based newborn care package, followed by antenatal care (tetanus toxoid, screening for pre-eclampsia, screening and treatment of asymptomatic bacteriuria and syphilis); skilled attendance at birth, offering first level maternal and neonatal care around childbirth; and emergency obstetric and neonatal care around and after birth. Screening and treatment of maternal syphilis, community based management of neonatal pneumonia, and steroids given during the antenatal period were relatively less cost effective in Sear-D. Scaling up all of the included interventions to 95% coverage would halve neonatal and maternal deaths. Conclusion Preventive interventions at the community level for newborn babies and at the primary care level for mothers and newborn babies are extremely cost effective, but the millennium development goals for maternal and child health will not be achieved without universal access to clinical services as well.

Population-based mammography screening and breast cancer incidence in New South Wales, Australia

To analyse breast cancer incidence trends in New South Wales (NSW), Australia, in relation to population-based mammography screening targeting women aged 50 to 69 years. Trends in age-specific incidence of invasive breast cancers in NSW women aged >= 40 years were examined in relation to mammography screening rates and screening cancer detection rates. Incidence of invasive breast cancer in NSW women increased in all age-groups over 1972 to 2002. The incidence trend for women aged 50 to 69 years showed that the steepest rise was associated with increased participation in population-based mammography screening, which was implemented from 1988 and achieved state-wide coverage in 1995. The elevated incidence of invasive cancer significantly exceeded pre-screening levels, and persisted after rates of initial screens declined. This elevated incidence was sustained by the contribution of cancers diagnosed through subsequent screening, and resulted from increased cancer detection rates in subsequent screens. The recent increase in invasive breast cancer incidence in NSW is associated with mammography screening, and occurred mostly in the target age-group women. Persistence of higher incidence after 1994 was not explicable by inflation of cancer incidence due to detection of prevalent screen cases, but was associated with a trend of increased cancer detection rates in subsequent screening rounds, probably consequent to quality improvements in mammography screening diagnosis.

The electrochemical corrosion of pure magnesium in 1 N NaCl

An electrochemical investigation was carried out to study the corrosion of pure magnesium in 1 N NaCl at different pH values involving electrochemical polarisation, scanning tunnel microscopy (STM), measurement of hydrogen gas evolution and measurement of the elements dissolved from the magnesium specimen which were determined by inductively coupled plasma atomic emission spectrophotometry (ICPAES). A partially protective surface film was a principal factor controlling corrosion. Film coverage decreased with increasing applied electrode potential. Application of a suitable external cathodic current density was shown to inhibit magnesium dissolution whilst at the same time the hydrogen evolution rate was relatively small. This showed that cathodic protection could be used to significantly reduce magnesium corrosion. A new definition is proposed for the negative difference effect (NDE). (C) 1997 Elsevier Science Ltd.

Autopathogenic T helper cell type 1 (Th1) and protective Th2 clones differ in their recognition of the autoantigenic peptide of myelin proteolipid protein

We previously generated a panel of T helper cell 1 (Th1) clones specific for an encephalitogenic peptide of myelin proteolipid protein (PLP) peptide 139-151 (HSLGKWLGHPDKF) that induces experimental autoimmune encephalomyelitis (EAE) upon adoptive transfer. In spite of the differences in their T cell receptor (TCR) gene usage, all these Th1 clones required W144 as the primary and most critical TCR contact residue for the activation. In this study, we determined the TCR contact residues of a panel of Th2/Th0 clones specific for the PLP peptide 139-151 generated either by immunization with the PLP 139-151 peptide with anti-B7-1 antibody or by immunization with an altered peptide Q144. Using alanine-substituted peptide analogues of the native PLP peptide, we show that the Th2 clones have shifted their primary contact residue to the NH2-terminal end of the peptide. These Th2 cells do not show any dependence on the W144, but show a critical requirement for L141/G142 as their major TCR contact residue. Thus, in contrast with the Th1 clones that did not proliferate to A144-substituted peptide, the Th2 clones tolerated a substitution at position 144 and proliferated to A144 peptide. This alternative A144 reactive repertoire appears to have a critical role in the regulation of autoimmune response to PLP 139-151 because preimmunization with A144 to expand the L141/G142-reactive repertoire protects mice from developing EAE induced with the native PLP 139-151 peptide. These data suggest that a balance between two different T cell repertoires specific for same autoantigenic epitope can determine disease phenotype, i.e., resistance or susceptibility to an autoimmune disease.

Chinese wool auctions: Failed agribusiness reform or future marketing channel?

The spectacular though short-lived operation of China's wool auctions graphically illustrates problems in reforming China's agribusiness sector. A selective coverage of product type and participants, a highly contrived process of price discovery, and an urgent need for parallel reform in related areas all led to the demise of the auctions and are a barrier to their re-emergence as a viable wool marketing channel. Despite the challenges facing wool auctions, this paper argues that they still have much to offer the marketing of wool in China.