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Sterile immunity against live Plasmodium infection can be achieved by immunization with radiation-attenuated sporozoites. This protection is known to be mediated in part by antigen-specific memory CD8+ T cells, presumably those residing in the liver. We characterized and compared the transcriptional profile of parasite-specific memory CD8+ T cells residing in the liver and spleen after immunization of mice with irradiated sporozoites. Microarray-based expression analysis of these memory CD8+ T cells indicated that liver-resident memory cells display a distinct gene expression profile. We found major differences in the expression of immune function genes as well as genes involved in the cell cycle, cell trafficking, transcription and intracellular signaling. Importantly, the malaria parasite-induced liver-resident CD8+ T cells display a transcriptional profile different to that described for CD8+ T cells following other microbial challenges. [ABSTRACT FROM AUTHOR]

Drug development performance is examined using data on clinical research projects of 10 pharmaceutical companies. In contrast to previous work on the discovery phase of pharmaceutical R&D we find a strong correlation between the diversity of firms' development efforts and the success probability of individual projects, but no effect of scale per se. Large firms' superior performance in drug development appears to be driven by returns to scope rather than returns to scale. Scope is confounded with firm fixed effects, however, suggesting an important role for inter-firm differences in the organization and management of the development function. [ABSTRACT FROM AUTHOR]

Background: Cancer patients have increased morbidity and mortality from COVID-19, but may respond poorly to vaccination. The Evaluation of COVID-19 Vaccination Efficacy and Rare Events in Solid Tumors (EVEREST) study, comparing seropositivity between cancer patients and healthy controls in a low SARS-CoV-2 community-transmission setting, allows determination of vaccine response with minimal interference from infection., Methods: Solid tumor patients from The Canberra Hospital, Canberra, Australia, and healthy controls who received COVID-19 vaccination between March 2021 and January 2022 were included. Blood samples were collected at baseline, pre-second vaccine dose and at 1, 3 (primary endpoint), and 6 months post-second dose. SARS-CoV-2 anti-spike-RBD (S-RBD) and anti-nucleocapsid IgG antibodies were measured., Results: Ninety-six solid tumor patients and 20 healthy controls were enrolled, with median age 62 years, and 60% were female. Participants received either AZD1222 (65%) or BNT162b2 (35%) COVID-19 vaccines. Seropositivity 3 months post vaccination was 87% (76/87) in patients and 100% (20/20) in controls (p = .12). Seropositivity was observed in 84% of patients on chemotherapy, 80% on immunotherapy, and 96% on targeted therapy (differences not satistically significant). Seropositivity in cancer patients increased from 40% (6/15) after first dose, to 95% (35/37) 1 month after second dose, then dropped to 87% (76/87) 3 months after second dose., Conclusion: Most patients and all controls became seropositive after two vaccine doses. Antibody concentrations and seropositivity showed a decrease between 1 and 3 months post vaccination, highlighting need for booster vaccinations. SARS-CoV-2 infection amplifies S-RBD antibody responses; however, cannot be adequately identified using nucleocapsid serology. This underlines the value of our COVID-naïve population in studying vaccine immunogenicity., (© 2024 The Authors. Asia‐Pacific Journal of Clinical Oncology published by John Wiley & Sons Australia, Ltd.)

The development of a vaccine is essential for the elimination of malaria. However, despite many years of effort, a successful vaccine has not been achieved. Most subunit vaccine candidates tested in clinical trials have provided limited efficacy, and thus attenuated whole-parasite vaccines are now receiving close scrutiny. Here, we test chemically attenuated Plasmodium yoelii 17X and demonstrate significant protection following homologous and heterologous blood-stage challenge. Protection against blood-stage infection persisted for at least 9 months. Activation of both CD4(+) and CD8(+) T cells was shown after vaccination; however, in vivo studies demonstrated a pivotal role for both CD4(+) T cells and B cells since the absence of either cell type led to loss of vaccine-induced protection. In spite of significant activation of circulating CD8(+) T cells, liver-stage immunity was not evident. Neither did vaccine-induced CD8(+) T cells contribute to blood-stage protection; rather, these cells contributed to pathogenesis, since all vaccinated mice depleted of both CD4(+) and CD8(+) T cells survived a challenge infection. This study provides critical insight into whole-parasite vaccine-induced immunity and strong support for testing whole-parasite vaccines in humans., (Copyright © 2016 Raja et al.)

Background: Between 80 and 90 million travellers visit malaria endemic areas annually and many require malaria chemoprophylaxis. The characterization of the risk and nature of eye disorders occurring during the use of malaria chemoprophylaxis is relevant for travel medicine advisors., Methods: We did a database analysis on eye disorder adverse events reported for mefloquine (as Lariam®) using the F. Hoffmann-La Roche global drug safety database for the time frame February 1984 to January 18th, 2011. These adverse event reports were reviewed by a trained ophthalmologist. The analysis focused on 3 categories of eye disorders--Category 1: visual acuity; Category 2: anatomical parts of the eye and Category 3: neuro-ophthalmic events. To put our analysis in context, an extensive literature search on "mefloquine" and "eye disorders" was conducted., Results: A total of 591 cases with 695 events assigned to the "Eye disorder" SOC in individuals exposed to mefloquine chemoprophylaxis were reported. The highest proportion of events (n = 493, 70.9%) was in Category 1: visual acuity (mainly visual impairment and blurred vision), followed by Category 3: neuro-ophthalmic events (n = 124, 17.8%). The majority of visual adverse events were non-serious but 37.7% (n = 223) of cases were classified as serious. Nine events of maculopathy were reported and 48 cases with 53 events described symptoms of optic neuropathy., Conclusions: Mefloquine, like other anti-malarials, may be associated with eye disorders. Prescribers of anti-malarials should inform travellers regarding the risk of potential ocular side effects. Users of chemoprophylaxis who experience visual disorders should be referred to an ophthalmologist., (Copyright © 2015. Published by Elsevier Ltd.)

Background: Sporozoite immunization of animals and humans under a chemo-prophylactic cover of chloroquine (CPS-CQ) efficiently induces sterile protection against malaria. In humans, CPS-CQ is strikingly more efficient than immunization with radiation attenuated sporozoites (RAS), raising the hypothesis that this might be partially due to CQ. Chloroquine, an established anti-malarial drug, is also well known for its immune modulating properties including improvement of cross-presentation. The aim of this study was to investigate whether co-administration of CQ during sporozoite immunization improves cellular responses and protective efficacy in Plasmodium berghei models., Methods: A number of experiments in selected complimentary P. berghei murine models in Balb/cByJ and C57BL/6j mice was performed. First, the effect of CQ administration on the induction of protection and immune responses by RAS immunization was studied. Next, the effect of CQ on the induction of circumsporozoite (CS) protein-specific CD8(+) T cells by immunization with P. berghei parasites expressing a mutant CS protein was investigated. Finally, a direct comparison of CPS-CQ to CPS with mefloquine (MQ), an anti-malarial with little known immune modulating effects, was performed., Results: When CQ was co-administered during immunization with graded numbers of RAS, this did not lead to an increase in frequencies of total memory CD8(+) T cells or CS protein-specific CD8(+) T cells. Also parasite-specific cytokine production and protection remained unaltered. Replacement of CQ by MQ for CPS immunization resulted in significantly reduced percentages of IFNγ producing memory T cells in the liver (p = 0.01), but similar protection., Conclusions: This study does not provide evidence for a direct beneficial effect of CQ on the induction of sporozoite-induced immune responses and protection in P. berghei malaria models. Alternatively, the higher efficiency of CPS compared to RAS might be explained by an indirect effect of CQ through limiting blood-stage exposure after immunization or to increased antigen exposure and, therefore, improved breadth of the immune response.

Malaria, which is caused by Plasmodium spp., starts with an asymptomatic phase, during which sporozoites, the parasite form that is injected into the skin by a mosquito, develop into merozoites, the form that infects erythrocytes. This pre-erythrocytic phase is still the most enigmatic in the parasite life cycle, but has long been recognized as an attractive vaccination target. In this Review, we present what has been learned in recent years about the natural history of the pre-erythrocytic stages, mainly using intravital imaging in rodents. We also consider how this new knowledge is in turn changing our understanding of the immune response mounted by the host against the pre-erythrocytic forms.

The study of pathogen immunity relies upon being able to track antigen specific immune responses and assess their protective capacity. To study immunity to Plasmodium antigens, chimeric rodent or human malaria parasites that express proteins from other Plasmodium species or unrelated species have been developed. Different types of chimeric parasites have been used to address a range of specific questions. Parasites expressing model T cell epitopes have been used to monitor cellular immune responses to the preerythrocytic and blood stages of malaria. Other parasites have been used to assess the functional significance of immune responses targeting particular proteins. Finally, a number of rodent malaria parasites that express vaccine-candidate antigens from P. falciparum and P. vivax have been used in functional assays of vaccine-induced antibody responses. Here, I review the experimental contributions that have been made using these parasites, and discuss the potential of these approaches to continue advancing our understanding of malaria immunology and vaccine research.

Ongoing research into the chaperone systems of malaria parasites, and particularly of Plasmodium falciparum, suggests that heat shock proteins (Hsps) could potentially be an excellent class of drug targets. The P. falciparum genome encodes a vast range and large number of chaperones, including 43 Hsp40, six Hsp70, and three Hsp90 proteins (PfHsp40s, PfHsp70s and PfHsp90s), which are involved in a number of fundamental cellular processes including protein folding and assembly, protein translocation, signal transduction and the cellular stress response. Despite the fact that Hsps are relatively conserved across different species, PfHsps do exhibit a considerable number of unique structural and functional features. One PfHsp90 is thought to be sufficiently different to human Hsp90 to allow for selective targeting. PfHsp70s could potentially be used as drug targets in two ways: either by the specific inhibition of Hsp70s by small molecule modulators, as well as disruption of the interactions between Hsp70s and co-chaperones such as the Hsp70/Hsp90 organising protein (Hop) and Hsp40s. Of the many PfHsp40s present on the parasite, there are certain unique or essential members which are considered to have good potential as drug targets. This review critically evaluates the potential of Hsps as malaria drug targets, as well as the use of chaperones as aids in the heterologous expression of other potential malarial drug targets.

With spending on biologics rising and patent expiry approaching for several blockbuster biologics, Congress and the Food and Drug Administration are considering creating a clear pathway for so-called follow-on biologics. Differences between drugs and biologics will affect market outcomes in various ways. Conservative budget impacts are appropriate in the short run because fewer competitors will enter, and average prices will drop less than was the case following the Hatch-Waxman Act. Over the long term, intellectual property provisions will be important considerations for policymakers designing a pathway for follow-on biologics that balances price competition and innovation incentives.

Background: Research is limited on physicians' compliance with recent clinical guidelines for asthma treatment., Objective: Our purpose was to investigate the relationships among clinical guidelines, asthma pharmacotherapy, and office-based visits through use of nationally representative data., Methods: Nationally representative data on prescribing patterns by office-based US physicians were extracted from the National Disease and Therapeutic Index. We tracked 1978-2002 trends in the frequency of asthma visits and patterns of asthma pharmacotherapy, focusing on the use of controller and reliever medications., Results: The estimated annual number of asthma visits in the United States increased continuously from 1978 through 1990 (18 million visits); since 1990, it has remained relatively stable. Controller medication use increased 8-fold between 1978 and 2002, inhaled corticosteroids manifesting the biggest increases. The use of reliever medications, particularly short-acting oral beta(2)-agonists, decreased modestly over this period. The aggregate use of controllers (83% of visits) superseded that of relievers (80%) for the first time in 2001. Improved appropriateness of asthma pharmacotherapy was also suggested by an increase in the controller-to-reliever ratio, which reached 92% in 2002. Xanthines, which once dominated asthma therapy (63% of visits in 1978), were used in only 2% of visits in 2002. More recent drug entrants have been adopted rapidly, single-entity long-acting inhaled beta(2)-agonists being used in 9% of visits and leukotriene modifiers in 24% of visits in 2002., Conclusion: Asthma pharmacotherapy has changed extensively in the past 25 years. Practices over the last decade are increasingly consistent with evidence-based guidelines. These changes in medication use might have contributed to the lack of a recent increase in asthma visits.

The mean number of complement receptor 1 (CR1) molecules on erythrocytes differs between normal individuals within the range of 100-1000 molecules per cell. In some disease states such as systemic lupus erythematosus (SLE), acquired immune deficiency syndrome (AIDS), insulin-dependent diabetes mellitus and malaria, erythrocyte CR1 levels are reduced and CR1 function may be impaired. Current methods for determining erythrocyte CR1 levels by flow cytometry require the use of freshly drawn blood samples because CR1 is lost from erythrocytes during storage. In order to facilitate field studies of associations between erythrocyte CR1 levels and disease, we have developed and validated an assay to quantify CR1 on both healthy and diseased erythrocytes that have been fixed in 5% formaldehyde or frozen in glycerol. These methods enable blood samples to be collected in areas lacking the facilities for flow cytometry and stored for later accurate quantification of CR1. Such procedures will be of particular benefit for future investigations of erythrocyte CR1 expression level and malaria susceptibility.

We examined the effects on work productivity of treatment with antihistamines in a retrospective study using linked health claims data and daily work output records for a sample of nearly 6000 claims processors at a large insurance company, between 1993 and 1995. We explained the variation in work output depending on the subjects' demographic characteristics, their jobs, and whether they were treated with "sedating" versus "nonsedating" antihistamines for nasal allergies. Differences of up to 13% in productivity were found after the subjects took sedating or nonsedating antihistamines. The observed effect suggests substantial indirect economic costs, which up to now have been largely overlooked because work productivity has proved difficult to measure objectively.

We model demand for four cephalosporins and compute own- and cross-price elasticities between branded and generic versions of the four drugs. We model demand as a multistage budgeting problem, and we argue that such a model is appropriate to the multistage nature of the purchase of pharmaceutical products, in particular the prescribing and dispensing stages. We find quite high elasticities between generic substitutes and also significant elasticities between some therapeutic substitutes.

We empirically examine interaction between the public and private sectors in pharmaceutical research using qualitative data on the drug discovery process and quantitative data on the incidence of coauthorship between public and private institutions. We find evidence of significant reciprocal interaction, and reject a simple "linear" dichotomous model in which the public sector performs basic research and the private sector exploits it. Linkages to the public sector differ across firms, reflecting variation in internal incentives and policy choices, and the nature of these linkages correlates with their research performance.

This paper studies a class of Poisson mixture models that includes covariates in rates. This model contains Poisson regression and independent Poisson mixtures as special cases. Estimation methods based on the EM and quasi-Newton algorithms, properties of these estimates, a model selection procedure, residual analysis, and goodness-of-fit test are discussed. A Monte Carlo study investigates implementation and model choice issues. This methodology is used to analyze seizure frequency and Ames salmonella assay data.

We examine the relationship between firm size and research productivity in the pharmaceutical industry. Using detailed internal firm data, we find that larger research efforts are more productive, not only because they enjoy economies of scale, but also because they realize economies of scope by sustaining diverse portfolios of research projects that capture internal and external knowledge spillovers. In pharmaceuticals, economies of scope in research are important in shaping the boundaries of the firm, and it may be worth tolerating the static efficiency loss attributable to the market power of large firms in exchange for their superior innovative performance.

Immunosuppressive therapy (IT) carries inherent risks involving the occurrence of lymphoproliferative disorders and malignancies (MA). The most frequently observed neoplasms in organ-transplant (OT) recipients treated with cyclosporine A (Cy-A) involve the skin and the lympho-reticular system. A disproportionally high percentage of the skin MA are Kaposi's sarcoma. Compared with a normal, not-exposed population matched for age, sex and country; Cy-A-treated OT recipients have a 28-times higher prevalence of lymphomas. This figure compares with a 34 to 59-fold increased risk in patients receiving conventional immunosuppressive therapy (CIT) for OT. However, it appears that in Cy-A-treated patients the latency period for the development of lymphomas is shorter than in patients on CIT. Other MA are increased seven-fold in Cy-A-treated patients and between two- and six-fold in those receiving CIT. The overall incidence of all types of MA is increased two-fold for Cy-A recipients and between two- and four-fold for those on CIT. Therefore patients receiving IT should be carefully monitored with respect to the possible occurrence of neoplasms.