Correlations between three ELISA protocols measurements of RTS,S/AS01-induced anti-CSP IgG antibodies

Background RTS,S/AS01 induced anti-circumsporozoite protein (CSP) IgG antibodies are associated with the vaccine efficacy. There is currently no international standardisation of the assays used in the measurement of anti-CSP IgG antibody concentrations for use in evaluations of the vaccine’s immunogenicity and/or efficacy. Here, we compared the levels of RTS,S/AS01 induced anti-CSP IgG antibodies measured using three different enzyme-Linked ImmunoSorbent Assays (ELISA). Methods 196 plasma samples were randomly selected from the 447 samples collected during the RTS,S/AS01 phase IIb trial in 2007 from Kenyan children aged between 5–17 months. The vaccine-induced anti-CSP IgG antibodies were then measured using two independently developed ELISA protocols (‘Kilifi-RTS,S’ and ‘Oxford-R21’) and compared to the results from the reference ‘Ghent-RTS,S’ protocol for the same participants. For each pair of protocols, a deming regression model was fitted. Linear equations were then derived to aid in conversions into equivalent ELISA units. The agreement was assessed using Bland and Altman method. Findings The anti-CSP IgG antibodies measured from the three ELISA protocols were in agreement, and were positively and linearly correlated; ‘Oxford’ and ‘Kilifi’ r = 0.93 (95% CI 0.91–0.95), ‘Oxford’ and ‘Ghent’ r = 0.94 (95% CI: 0.92–0.96), and ‘Kilifi’ and ‘Ghent’ r = 0.97 (95% CI: 0.96–0.98), p<0.0001 for all correlations. Conclusions With the linearity, agreement and correlations established between the assays, conversion equations can be applied to convert results into equivalent units, enabling comparisons of immunogenicities across different vaccines of the same CSP antigens. This study highlights the need for the international harmonisation of anti-CSP antibody measurements

Niches for Species, a multi-species model to guide woodland management: An example based on Scotland's native woodlands

Designating and managing areas with the aim of protecting biodiversity requires information on species distributions and habitat associations, but a lack of reliable occurrence records for rare and threatened species precludes robust empirical modelling. Managers of Scotland’s native woodlands are obliged to consider 208 protected species, which each have their own, narrow niche requirements. To support decision-making, we developed Niches for Species (N4S), a model that uses expert knowledge to predict the potential occurrence of 179 woodland protected species representing a range of taxa: mammals, birds, invertebrates, fungi, bryophytes, lichens and vascular plants. Few existing knowledge-based models have attempted to include so many species. We collated knowledge to define each species’ suitable habitat according to a hierarchical habitat classification: woodland type, stand structure and microhabitat. Various spatial environmental datasets were used singly or in combination to classify and map Scotland’s native woodlands accordingly, thus allowing predictive mapping of each species’ potential niche. We illustrate how the outputs can inform individual species management, or can be summarised across species and regions to provide an indicator of woodland biodiversity potential for landscape scale decisions. We tested the model for ten species using available occurrence records. Although concordance between predicted and observed distributions was indicated for nine of these species, this relationship was statistically significant in only five cases. We discuss the difficulties in reliably testing predictions when the records available for rare species are typically low in number, patchy and biased, and suggest future model improvements. Finally, we demonstrate how using N4S to synthesise complex, multi-species information into an easily digestible format can help policy makers and practitioners consider large numbers of species and their conservation needs

Correlations between three ELISA protocols measurements of RTS,S/AS01-induced anti-CSP IgG antibodies

Background RTS,S/AS01 induced anti-circumsporozoite protein (CSP) IgG antibodies are associated with the vaccine efficacy. There is currently no international standardisation of the assays used in the measurement of anti-CSP IgG antibody concentrations for use in evaluations of the vaccine’s immunogenicity and/or efficacy. Here, we compared the levels of RTS,S/AS01 induced anti-CSP IgG antibodies measured using three different enzyme-Linked ImmunoSorbent Assays (ELISA). Methods 196 plasma samples were randomly selected from the 447 samples collected during the RTS,S/AS01 phase IIb trial in 2007 from Kenyan children aged between 5–17 months. The vaccine-induced anti-CSP IgG antibodies were then measured using two independently developed ELISA protocols (‘Kilifi-RTS,S’ and ‘Oxford-R21’) and compared to the results from the reference ‘Ghent-RTS,S’ protocol for the same participants. For each pair of protocols, a deming regression model was fitted. Linear equations were then derived to aid in conversions into equivalent ELISA units. The agreement was assessed using Bland and Altman method. Findings The anti-CSP IgG antibodies measured from the three ELISA protocols were in agreement, and were positively and linearly correlated; ‘Oxford’ and ‘Kilifi’ r = 0.93 (95% CI 0.91–0.95), ‘Oxford’ and ‘Ghent’ r = 0.94 (95% CI: 0.92–0.96), and ‘Kilifi’ and ‘Ghent’ r = 0.97 (95% CI: 0.96–0.98), p<0.0001 for all correlations. Conclusions With the linearity, agreement and correlations established between the assays, conversion equations can be applied to convert results into equivalent units, enabling comparisons of immunogenicities across different vaccines of the same CSP antigens. This study highlights the need for the international harmonisation of anti-CSP antibody measurements

Patient-reported outcomes of periacetabular osteotomy from the prospective ANCHOR cohort study

BACKGROUND: Current literature describing the periacetabular osteotomy (PAO) is mostly limited to retrospective case series. Larger, prospective cohort studies are needed to provide better clinical evidence regarding this procedure. The goals of the current study were to (1) report minimum 2-year patient-reported outcomes (pain, hip function, activity, overall health, and quality of life), (2) investigate preoperative clinical and disease characteristics as predictors of clinical outcomes, and (3) report the rate of early failures and reoperations in patients undergoing contemporary PAO surgery. METHODS: A large, prospective, multicenter cohort of PAO procedures was established, and outcomes at a minimum of 2 years were analyzed. A total of 391 hips were included for analysis (79% of the patients were female, and the average patient age was 25.4 years). Patient-reported outcomes, conversion to total hip replacement, reoperations, and major complications were documented. Variables with a p value of ≤0.10 in the univariate linear regressions were included in the multivariate linear regression. The backward stepwise selection method was used to determine the final risk factors of clinical outcomes. RESULTS: Clinical outcome analysis demonstrated major clinically important improvements in pain, function, quality of life, overall health, and activity level. Increasing age and a body mass index status of overweight or obese were predictive of improved results for certain outcome metrics. Male sex and mild acetabular dysplasia were predictive of lesser improvements in certain outcome measures. Three (0.8%) of the hips underwent early conversion to total hip arthroplasty, 12 (3%) required reoperation, and 26 (7%) experienced a major complication. CONCLUSIONS: This large, prospective cohort study demonstrated the clinical success of contemporary PAO surgery for the treatment of symptomatic acetabular dysplasia. Patient and disease characteristics demonstrated predictive value that should be considered in surgical decision-making. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence

Cumulative impact assessments of multiple host species loss from plant diseases show disproportionate reductions in associated biodiversity

Funding Information: This work was funded by BBSRC grant Protecting Oak Ecosystems (PuRpOsE): BB/N022831/1 with additional funding from the Scottish Government's Rural and Environment Research and Analysis Directorate 2016–2021 strategic research programme. The authors thank Nick Hodgetts for collating the lists of the bryophyte species associated with ash and oak, Ralph Harmer for conducting some of the site visits and the site owners for allowing us access to the sites. Katharine Preedy provided statistical advice. Steve Albon and Robin Pakeman kindly provided comments to improve earlier drafts.Peer reviewe

Cumulative impact assessments of multiple host species loss from plant diseases show disproportionate reductions in associated biodiversity

Non-native plant pests and pathogens are increasing exponentially, causing extirpation of foundation species. The impact of large-scale declines in a single host on associated biodiversity is widely documented. However, the impact of multiple host loss on biodiversity and whether these impacts are multiplicative has not been assessed. Ecological theory suggests that systems with greater functional redundancy (alternative hosts) will be more resilient to the loss of sympatric hosts. We test this theory and show its importance in relation to pest/pathogen impact assessments. We assessed the potential impact on biodiversity of the loss of two widely occurring sympatric European tree species, Fraxinus excelsior and Quercus petraea/robur, both of which are currently threatened by a range of pests and pathogens. At the UK scale, the total number of associated species at risk of extirpation from plant diseases affecting these two sympatric hosts is greater than the sum of the associated species at risk from declines in either host alone. F. excelsior hosts 45 obligate species (species only found on that host) and Q. petraea/robur hosts 326. However, a decline in both these trees would impact 512 associated species, across multiple taxon groups, a 38% increase. Assessments at a local scale, 24 mixed F. excelsior–Q. petraea/robur woodlands revealed that these impacts may be even greater due to a lack of functional redundancy. Only 21% of sites were able to provide functional redundancy for F. excelsior and Q. petraea/robur associated species which can use other tree species. In most woodlands, the tree species required to provide functional redundancy were not present, although the site conditions were often suitable for them to grow. Synthesis. Understanding of functional redundancy should be applied to assessments of pests/pathogens impact on biodiversity. In risk assessments, higher impact scores should be given to pests/pathogens affecting hosts occurring with other host plant species already impacted by pests/pathogens. Current pest/pathogen risk assessment approaches that ignore the cumulative, cascading effects shown in this study may allow an insidious, mostly overlooked, driver of biodiversity loss to continue.Biotechnology and Biological Sciences Research Council, Grant/Award Number: BB/N022831/1; Rural and Environment Science and Analytical Services Division.info:eu-repo/semantics/publishedVersio

Bimodal dynamics of granular organelles in primary renin-expressing cells revealed using TIRF microscopy

Renin is the initiator and rate-limiting factor in the renin-angiotensin blood pressure regulation system. Although renin is not exclusively produced in the kidney, in nonmurine species the synthesis and secretion of the active circulatory enzyme is confined almost exclusively to the dense core granules of juxtaglomerular (JG) cells, where prorenin is processed and stored for release via a regulated pathway. Despite its importance, the structural organization and regulation of granules within these cells is not well understood, in part due to the difficulty in culturing primary JG cells in vitro and the lack of appropriate cell lines. We have streamlined the isolation and culture of primary renin-expressing cells suitable for high-speed, high-resolution live imaging using a Percoll gradient-based procedure to purify cells from RenGFP+ transgenic mice. Fibronectin-coated glass coverslips proved optimal for the adhesion of renin-expressing cells and facilitated live cell imaging at the plasma membrane of primary renin cells using total internal reflection fluorescence microscopy (TIRFM). To obtain quantitative data on intracellular function, we stained mixed granule and lysosome populations with Lysotracker Red and stimulated cells using 100 nM isoproterenol. Analysis of membrane-proximal acidic granular organelle dynamics and behavior within renin-expressing cells revealed the existence of two populations of granular organelles with distinct functional responses following isoproterenol stimulation. The application of high-resolution techniques for imaging JG and other specialized kidney cells provides new opportunities for investigating renal cell biology

A single dose of ChAdOx1 Chik vaccine induces neutralising antibodies against four chikungunya virus lineages in a phase 1 clinical trial

Chikungunya virus (CHIKV) is a reemerging mosquito-borne virus that causes swift outbreaks. Major concerns are the persistent and disabling polyarthralgia in infected individuals. Here we present the results from a first-in-human trial of the candidate simian adenovirus vectored vaccine ChAdOx1 Chik, expressing the CHIKV full-length structural polyprotein (Capsid, E3, E2, 6k and E1). 24 adult healthy volunteers aged 18–50 years, were recruited in a dose escalation, open-label, nonrandomized and uncontrolled phase 1 trial (registry NCT03590392). Participants received a single intramuscular injection of ChAdOx1 Chik at one of the three preestablished dosages and were followed-up for 6 months. The primary objective was to assess safety and tolerability of ChAdOx1 Chik. The secondary objective was to assess the humoral and cellular immunogenicity. ChAdOx1 Chik was safe at all doses tested with no serious adverse reactions reported. The vast majority of solicited adverse events were mild or moderate, and self-limiting in nature. A single dose induced IgG and Tcell responses against the CHIKV structural antigens. Broadly neutralizing antibodies against the four CHIKV lineages were found in all participants and as early as 2 weeks after vaccination. In summary, ChAdOx1 Chik showed excellent safety, tolerability and 100% PRNT50 seroconversion after a single dose

The public health impact and cost-effectiveness of the R21/Matrix-M malaria vaccine: a mathematical modelling study

Background The R21/Matrix-M vaccine has demonstrated high efficacy against Plasmodium falciparum clinical malaria in children in sub-Saharan Africa. Using trial data, we aimed to estimate the public health impact and cost-effectiveness of vaccine introduction across sub-Saharan Africa. Methods We fitted a semi-mechanistic model of the relationship between anti-circumsporozoite protein antibody titres and vaccine efficacy to data from 3 years of follow-up in the phase 2b trial of R21/Matrix-M in Nanoro, Burkina Faso. We validated the model by comparing predicted vaccine efficacy to that observed over 12–18 months in the phase 3 trial. Integrating this framework within a mathematical transmission model, we estimated the cases, malaria deaths, and disability-adjusted life-years (DALYs) averted and cost-effectiveness over a 15-year time horizon across a range of transmission settings in sub-Saharan Africa. Cost-effectiveness was estimated incorporating the cost of vaccine introduction (dose, consumables, and delivery) relative to existing interventions at baseline. We report estimates at a median of 20% parasite prevalence in children aged 2–10 years (PfPR2–10) and ranges from 3% to 65% PfPR2–10. Findings Anti-circumsporozoite protein antibody titres were found to satisfy the criteria for a surrogate of protection for vaccine efficacy against clinical malaria. Age-based implementation of a four-dose regimen of R21/Matrix-M vaccine was estimated to avert 181 825 (range 38 815–333 491) clinical cases per 100 000 fully vaccinated children in perennial settings and 202 017 (29 868–405 702) clinical cases per 100 000 fully vaccinated children in seasonal settings. Similar estimates were obtained for seasonal or hybrid implementation. Under an assumed vaccine dose price of USD 3, the incremental cost per clinical case averted was USD 7 (range 4–48) in perennial settings and USD 6 (3–63) in seasonal settings and the incremental cost per DALY averted was USD 34 (29–139) in perennial settings and USD 30 (22–172) in seasonal settings, with lower cost-effectiveness ratios in settings with higher PfPR2–10. Interpretation Introduction of the R21/Matrix-M malaria vaccine could have a substantial public health benefit across sub-Saharan Africa. Funding The Wellcome Trust, the Bill & Melinda Gates Foundation, the UK Medical Research Council, the European and Developing Countries Clinical Trials Partnership 2 and 3, the NIHR Oxford Biomedical Research Centre, and the Serum Institute of India, Open Philanthropy

The Knee Clinical Assessment Study – CAS(K). A prospective study of knee pain and knee osteoarthritis in the general population: baseline recruitment and retention at 18 months

BACKGROUND: Selective non-participation at baseline (due to non-response and non-consent) and loss to follow-up are important concerns for longitudinal observational research. We investigated these matters in the context of baseline recruitment and retention at 18 months of participants for a prospective observational cohort study of knee pain and knee osteoarthritis in the general population. METHODS: Participants were recruited to the Knee Clinical Assessment Study – CAS(K) – by a multi-stage process involving response to two postal questionnaires, consent to further contact and medical record review (optional), and attendance at a research clinic. Follow-up at 18-months was by postal questionnaire. The characteristics of responders/consenters were described for each stage in the recruitment process to identify patterns of selective non-participation and loss to follow-up. The external validity of findings from the clinic attenders was tested by comparing the distribution of WOMAC scores and the association between physical function and obesity with the same parameters measured directly in the target population as whole. RESULTS: 3106 adults aged 50 years and over reporting knee pain in the previous 12 months were identified from the first baseline questionnaire. Of these, 819 consented to further contact, responded to the second questionnaire, and attended the research clinics. 776 were successfully followed up at 18 months. There was evidence of selective non-participation during recruitment (aged 80 years and over, lower socioeconomic group, currently in employment, experiencing anxiety or depression, brief episode of knee pain within the previous year). This did not cause significant bias in either the distribution of WOMAC scores or the association between physical function and obesity. CONCLUSION: Despite recruiting a minority of the target population to the research clinics and some evidence of selective non-participation, this appears not to have resulted in significant bias of cross-sectional estimates. The main effect of non-participation in the current cohort is likely to be a loss of precision in stratum-specific estimates e.g. in those aged 80 years and over. The subgroup of individuals who attended the research clinics and who make up the CAS(K) cohort can be used to accurately estimate parameters in the reference population as a whole. The potential for selection bias, however, remains an important consideration in each subsequent analysis