Health literacy, governance and systems leadership contribute to the implementation of the One Health approach: a virtuous circle

One Health is an important approach to addressing health threats and promoting health through interdisciplinary health, policy, legislation and leadership research to achieve better human and animal health and better outcomes for the planet. The Covid-19 pandemic has triggered an urgent awareness of the need to develop innovative integrative solutions to address root causes of such threats to health, which requires collaboration across disciplines and amongst different sectors and communities. We explore how achieving the Quadripartite Organizations' One Health Joint Plan of Action can be supported by the concepts of 'One Health literacy' and 'One Health governance' and promote both academic and policy dialogue. We show how One Health literacy and One Health governance influence and reinforce each other, while an interdisciplinary systems leadership approach acts as a catalyst and mechanism for understanding and enacting change. Based on our understanding of how these elements influence the implementation of the One Health approach, we describe a model for considering how external triggering events such as the Covid-19 pandemic may prompt a virtuous circle whereby exposure to and exploration of One Health issues may lead to improved One Health literacy and to better governance. We close with recommendations to international organisations, national governments and to leaders in policy, research and practice to enhance their influence on society, the planetary environment, health and well-being.

Health economic evaluation of a nurse-led care model from the nursing home perspective focusing on residents' hospitalisations

BACKGROUND

Health economic evaluations of the implementation of evidence-based interventions (EBIs) into practice provide vital information but are rarely conducted. We evaluated the health economic impact associated with implementation and intervention of the INTERCARE model-an EBI to reduce hospitalisations of nursing home (NH) residents-compared to usual NH care.

METHODS

The INTERCARE model was conducted in 11 NHs in Switzerland. It was implemented as a hybrid type 2 effectiveness-implementation study with a multi-centre non-randomised stepped-wedge design. To isolate the implementation strategies' costs, time and other resources from the NHs' perspective, we applied time-driven activity-based costing. To define its intervention costs, time and other resources, we considered intervention-relevant expenditures, particularly the work of the INTERCARE nurse-a core INTERCARE element. Further, the costs and revenues from the hotel and nursing services were analysed to calculate the NHs' losses and savings per resident hospitalisation. Finally, alongside our cost-effectiveness analysis (CEA), a sensitivity analysis focused on the intervention's effectiveness-i.e., regarding reduction of the hospitalisation rate-relative to the INTERCARE costs. All economic variables and CEA were assessed from the NHs' perspective.

RESULTS

Implementation strategy costs and time consumption per bed averaged 685CHF and 9.35 h respectively, with possibilities to adjust material and human resources to each NH's needs. Average yearly intervention costs for the INTERCARE nurse salary per bed were 939CHF with an average of 1.4 INTERCARE nurses per 100 beds and an average employment rate of 76% of full-time equivalent per nurse. Resident hospitalisation represented a total average loss of 52% of NH revenues, but negligible cost savings. The incremental cost-effectiveness ratio of the INTERCARE model compared to usual care was 22'595CHF per avoided hospitalisation. As expected, the most influential sensitivity analysis variable regarding the CEA was the pre- to post-INTERCARE change in hospitalisation rate.

CONCLUSIONS

As initial health-economic evidence, these results indicate that the INTERCARE model was more costly but also more effective compared to usual care in participating Swiss German NHs. Further implementation and evaluation of this model in randomised controlled studies are planned to build stronger evidential support for its clinical and economic effectiveness.

TRIAL REGISTRATION

clinicaltrials.gov ( NCT03590470 ).

Positive effect of the INTERCARE nurse-led model on reducing nursing home transfers: A nonrandomized stepped-wedge design

Background

Unplanned nursing home (NH) transfers are burdensome for residents and costly for health systems. Innovative nurse‐led models of care focusing on improving in‐house geriatric expertise are needed to decrease unplanned transfers. The aim was to test the clinical effectiveness of a comprehensive, contextually adapted geriatric nurse‐led model of care (INTERCARE) in reducing unplanned transfers from NHs to hospitals.

Methods

A multicenter nonrandomized stepped‐wedge design within a hybrid type‐2 effectiveness‐implementation study was implemented in 11 NHs in German‐speaking Switzerland. The first NH enrolled in June 2018 and the last in November 2019. The study lasted 18 months, with a baseline period of 3 months for each NH. Inclusion criteria were 60 or more long‐term care beds and 0.8 or more hospitalizations per 1′000 resident care days. Nine hundred and forty two long‐term NH residents were included between June 2018 and January 2020 with informed consent. Short‐term residents were excluded. The primary outcome was unplanned hospitalizations. A fully anonymized dataset of overall transfers of all NH residents served as validation. Analysis was performed with segmented mixed regression modeling.

Results

Three hundred and three unplanned and 64 planned hospitalizations occurred. During the baseline period, unplanned transfers increased over time (β₁ = 0.52), after which the trend significantly changed by a similar but opposite amount (β₂ = −0.52; p = 0.0001), resulting in a flattening of the average transfer rate throughout the postimplementation period (β₁ + β₂ ≈ 0). Controlling for age, gender, and cognitive performance did not affect these trends. The validation set showed a similar flattening trend.

Conclusion

A complex intervention with six evidence‐based components demonstrated effectiveness in significantly reducing unplanned transfers of NH residents to hospitals. INTERCARE's success was driven by registered nurses in expanded roles and the use of tools for clinical decision‐making.

See related Editorial by Kaehr et al. in this issue.

Strengthening Geriatric Expertise in Swiss Nursing Homes: INTERCARE Implementation Study Protocol

OBJECTIVES

Nursing home (NH) residents with complex care needs ask for attentive monitoring of changes and appropriate in-house decision making. However, access to geriatric expertise is often limited with a lack of geriatricians, general practitioners, and/or nurses with advanced clinical skills, leading to potentially avoidable hospitalizations. This situation calls for the development, implementation, and evaluation of innovative, contextually adapted nurse-led care models that support NHs in improving their quality of care and reducing hospitalizations by investing in effective clinical leadership, geriatric expertise, and care coordination.

DESIGN

An effectiveness-implementation hybrid type 2 design to assess clinical outcomes of a nurse-led care model and a mixed-method approach to evaluate implementation outcomes will be applied. The model development, tailoring, and implementation are based on the Consolidated Framework for Implementation Research (CFIR).

SETTING

NHs in the German-speaking region of Switzerland.

PARTICIPANTS

Eleven NHs were recruited. The sample size was estimated assuming an average of .8 unplanned hospitalizations/1000 resident days and a reduction of 25% in NHs with the nurse-led care model.

INTERVENTION

The multilevel complex context-adapted intervention consists of six core elements (eg, specifically trained INTERCARE nurses or evidence-based tools like Identify, Situation, Background, Assessment and Recommendation [ISBAR]). Multilevel implementation strategies include leadership and INTERCARE nurse training and support.

MEASUREMENTS

The primary outcomes are unplanned hospitalizations/1000 care days. Secondary outcomes include unplanned emergency department visits, quality indicators (eg, physical restraint use), and costs. Implementation outcomes included, for example, fidelity to the model's core elements.

CONCLUSION

The INTERCARE study will provide evidence about the effectiveness of a nurse-led care model in the real-world setting and accompanying implementation strategies. J Am Geriatr Soc 67:2145-2150, 2019.

[Patient's own medications in a Swiss regional hospital: where are we and where should we go?]

OBJECTIVE

The use of patient's own medications (POMs) during inpatient admissions may represent a risk if not adequately supervised. The objective of this work was: (i) to assess the management of POMs in our hospital, and (ii) to identify actions to assure this practice.

METHODS

A questionnaire survey was conducted among caregivers of the medical, surgery and geriatric units of a Swiss regional hospital. Six criteria for appropriate management of POMs were identified from the literature and internal consensus. Based on this survey and data from literature, the investigators identified relevant actions to be implemented for optimizing the management of POMs.

RESULTS

Out of the 21 included units, 3 already set an inner written POMs policy, and 3 managed POM in accordance with selected criteria. The main issues were that POMs were mainly stored in the patient's room, and that quality criteria were not systematically checked before POMs' administration. POMs were mainly used to ensure continuity of treatment. Two thirds of the units systematically returned POMs to the patients upon discharge, but rarely sorted them out before recovery. Ten actions were identified to secure the management of POMs.

CONCLUSION

These results confirm that POMs are commonly used and indicate a potential for improvement in the management of POMs in our hospital. An institutional guideline is now planned to support the implementation of the identified actions.

Beliefs and implementation of evidence-based practice among nurses and allied healthcare providers in the Valais hospital, Switzerland

RATIONALE

Evidence-based practice (EBP) is upheld as a means for patients to receive the most efficient care in a given context. Despite the available evidence and positive beliefs about it, implementing EBP as standard daily practice still faces many obstacles.

AIMS AND OBJECTIVES

This study investigated the beliefs about and implementation of EBP among nurses and allied healthcare providers (AHP) in 9 acute care hospitals in the canton of Valais, Switzerland.

MATERIALS AND METHODS

A cross-sectional descriptive survey was conducted. The target population was composed of 1899 nurses and 126 AHPs. Beliefs about and implementation of EBP were measured using EBP-Beliefs and EBP-Implementation scales of Melnyk et al.

RESULTS

The initial sample consisted in 491 participants (overall response rate 24.2%): 421 nurses (22.4% response rate) and 78 AHPs (61.9% response rate). The final sample, composed only of those who declared previous exposure to EBP, included 391 participants (329 nurses and 62 AHPs). Overall, participants had positive attitudes towards EBP and were willing to increase their knowledge to guide practice. However, they acknowledged poor implementation of EBP in daily practice. A significantly higher level of EBP implementation was declared by those formally trained in it (P = 0.006) and by those occupying more senior professional functions (P = 0.004). EBP-Belief scores predicted 13% of the variance in the EBP-Implementation scores (R²  = 0.13).

DISCUSSION

EBP is poorly implemented despite positive beliefs about it. Continuing education and support on EBP would help to ensure that patients receive the best available care based on high-quality evidence, patient needs, clinical expertise, and a fair distribution of healthcare resources.

CONCLUSION

This study's results will be used to guide institutional strategy to increase the use of EBP in daily practice.

A multi-method study on the quality of the nurse work environment in acute-care hospitals: positioning Switzerland in the Magnet hospital research

BACKGROUND

Magnet hospitals share nurse work environment characteristics associated with superior patient, nurse and financial outcomes. In Switzerland, however, it is uncertain how nurses appraise their work environments.

OBJECTIVES

To describe the quality of the nurse work environment in 35 Swiss acute care hospitals and to benchmark findings based on international Magnet hospital research.

METHOD

This study used two data sources: (1) the Swiss arm of the RN4CAST study; and (2) a structured literature review. Hospitals were categorised based on Magnet and non-Magnet data. Our outcome variable of interest was the quality of nurse work environment measured with the Practice Environment Scale of the Nurse Work Index (PES-NWI).

RESULTS

We reviewed 13 American, Canadian, and Australian studies of acute-care hospitals. Three provided Magnet hospitals' nurse work environment data, and all included non-Magnet hospitals' data. Swiss hospitals' evaluations on nurse work environment quality varied widely, but 25% achieved scores indicating "Magnet nurse work environments". Swiss hospitals' average "Nursing manager ability" subscale scores fulfilled Magnet hospital criteria, although "Nurse participation in hospital affairs" and "Nursing staffing and resource adequacy" scores neared non-Magnet levels.

CONCLUSION

On average, our results indicated high quality nurse work environments in Swiss hospitals. Implementing Magnet model organisational principles might be a valuable approach for Swiss acute-care hospitals to both improve mixed and unfavourable nurse work environments and to improve nurse and patient outcomes. National benchmarking of nurse work environments and other nurse-sensitive indicators may facilitate evaluating the impact of current developments in Swiss healthcare.

Analysis of PCDD/Fs and dioxin-like PCBs in atmospheric deposition samples from the Flemish measurement network: correlation between the CALUX bioassay and GC-HRMS

Since the CALUX (Chemically Activated LUciferase gene eXpression) bioassay is a fast, sensitive and inexpensive tool for the analysis of a high number of samples, the use of this technique in routine analysis of atmospheric deposition samples may be a valuable alternative for GC-HRMS. In this study, a validated CALUX method was used for the analysis of PCDD/Fs and dioxin-like PCBs in more than 90 atmospheric deposition samples for different locations in Flanders. The samples were taken in residential and agricultural areas, where a threshold limit of 21pgWHO-TEQm(-2)d(-1) for the sum of PCDD/Fs and dioxin-like PCBs was set, and in industrial zones and natural reserves, where no official threshold limit is available. The results from the Flemish measurement program showed correlation between CALUX and GC-HRMS for all the samples, originating from the different areas (R(2) of 0.81, 0.53 and 0.64 for dl-PCBs, PCDD/Fs and sum of both fractions, respectively). Median CALUX/GC-HRMS ratios of 2.0, 0.9 and 1.3 were reported for the PCDD/Fs, dioxin-like PCBs and the sum of both fractions, respectively. The results show that the CALUX bioassay is a valuable alternative tool for the classic GC-HRMS analysis of atmospheric deposition samples in the Flemish measurement network.

The association of patient safety climate and nurse-related organizational factors with selected patient outcomes: a cross-sectional survey

BACKGROUND

Patient safety climate (PSC) is an important work environment factor determining patient safety and quality of care in healthcare organizations. Few studies have investigated the relationship between PSC and patient outcomes, considering possible confounding effects of other nurse-related organizational factors.

OBJECTIVE

The purpose of this study was to explore the relationship between PSC and patient outcomes in Swiss acute care hospitals, adjusting for major organizational variables.

METHODS

This is a sub-study of the Swiss arm of the multicenter-cross sectional RN4CAST (Nurse Forecasting: Human Resources Planning in Nursing) study. We utilized data from 1630 registered nurses (RNs) working in 132 surgical, medical and mixed surgical-medical units within 35 Swiss acute care hospitals. PSC was measured with the 9-item Safety Organizing Scale. Other organizational variables measured with established instruments included the quality of the nurse practice environment, implicit rationing of nursing care, nurse staffing, and skill mix levels. We performed multilevel multivariate logistic regression to explore relationships between seven patient outcomes (nurse-reported medication errors, pressure ulcers, patient falls, urinary tract infection, bloodstream infection, pneumonia; and patient satisfaction) and PSC.

RESULTS

In none of our regression models was PSC a significant predictor for any of the seven patient outcomes. From our nurse-related organizational variables, the most robust predictor was implicit rationing of nursing care. After controlling for major organizational variables and hierarchical data structure, higher levels of implicit rationing of nursing care resulted in significant decrease in the odds of patient satisfaction (OR=0.276, 95%CI=0.113-0.675) and significant increase in the odds of nurse reported medication errors (OR=2.513, 95%CI=1.118-5.653), bloodstream infections (OR=3.011, 95%CI=1.429-6.347), and pneumonia (OR=2.672, 95%CI=1.117-6.395).

CONCLUSIONS

We failed to confirm our hypotheses that PSC is related to improved patient outcomes, which we need to re-test with more reliable outcome measures, such as 30-day patient mortality. Based on our findings, general medical/surgical units should monitor the rationing of nursing care levels which may help to detect imbalances in the "work system", such as inadequate nurse staffing or skill mix levels to meet patients' needs.

Analysis of PCDD/Fs and dioxin-like PCBs in atmospheric deposition samples from the Flemish measurement network: Optimization and validation of a new CALUX bioassay method

Since the CALUX (Chemically Activated LUciferase gene eXpression) bioassay is a fast, sensitive and inexpensive tool for the analysis of a high number of samples, validation of new methods is urgently needed. In this study, a new method for the analysis of PCDD/Fs and dioxin-like PCBs in atmospheric deposition samples with the CALUX bioassay was developed, optimized and validated. The method consists of 4 steps: filtration, extraction, clean up and bioassay analysis. To avoid the use of large amounts of toxic solvents, new techniques were used for filtration and extraction: a C18 filter was used instead of a liquid/liquid extraction and an Accelerated Solvent Extractor (ASE) was used instead of the traditional soxhlet extraction. After pre-oxidation of the sample extract, clean up was done using a multi-layer silica gel column coupled to a carbon column. The PCDD/F and PCB fractions were finally analyzed with the H1L7.5c1 and/or the H1L6.1c3 mouse hepatoma cell lines. The limit of quantification was 1.4pg CALUX-BEQm(-2)d(-1) for the PCBs and 5.6pgCALUX-BEQm(-2)d(-1) for the PCDD/Fs, when using the new sensitive H1L7.5c1 cell line. The GC-HRMS recovery for all PCDD/F congeners was between 55% and 112%, with a mean recovery of 90%. CALUX recoveries of spiked procedural blanks were between the accepted ranges of 80-120%. Repeatability and reproducibility were satisfactory and no interferences from metals were detected. The first results from the Flemish measurement program showed good correlation between CALUX and GC-HRMS.

Cartilaginous choristoma of the oral cavity: a report of two cases

A choristoma is a tumour-like mass of normal cells in an abnormal location. Intra-oral choristomas are rare lesions. We report on two cases of cartilaginous choristoma, one in the tongue, the most frequently involved oral structure, and another in the upper oral vestibule. We discuss the lesion's clinical features and their differential diagnosis. The widely accepted metaplastic, embryonal and tumoral histopathologenetic theories are discussed. Surgical excision is the treatment of choice, and no recurrence has been reported.

Effect of backyard burning on dioxin deposition and air concentrations

The influence from open burning of garden and household waste on locally measured dioxin deposition and air concentrations was evaluated in three sets of experiments: the combustion of garden waste in barrels and in open fires, and the incineration of household waste in an empty oil drum. Each set was composed of eight individual experiments over 4 h. Deposition gauges were located 20 m NE, SE, SW and NW with respect to the source and on a background location at 400 m SW. Air samples were taken in the plume with a medium volume sampler equipped with a quartz filter and a polyurethane plug. The results illustrate deposition increments in the wind direction at a distance of 20 m from the source of 0.8 pg TEQ/m2 day for garden waste and 2.5 pg TEQ/m2 day for household waste. Concentrations in the plume were increased by 160-580 fg TEQ/m3 over a period of 12 and 31 h respectively. Expressed at a reference CO2 concentration of 9% this corresponds with a range from 0.8 to 3.6 ng TEQ/m3, which is comparable with a poorly controlled MSWI. Emission factors in the order of magnitude of 4.5 ng TEQ/kg combusted garden waste and 35 ng TEQ/kg burned municipal waste were determined.

Palliative home care: improving co-operation between the specialist team and the family doctor

The aim of this study is to ascertain family doctors' opinions of the home care services dispensed by a specialist palliative care team. Fifty-six doctors responded to the questionnaire they had been sent. Ninety-four per cent of them were satisfied with the team's intervention. The highest satisfaction ratings were those for the provision of specialist medical equipment, technical competence and medical support. The lowest ratings were for information coming from the team and for recognition of the practitioner as the primary carer. Among these items, information, regard for the doctor's role and medical support are closely correlated to the practitioners' overall index of satisfaction. The palliative care team answered a mirror questionnaire. It found its availability, its speed of intervention, its technical competence, and its regard for the doctor's role very satisfactory. It was less satisfied with the information, medical support and psychosocial support it provided. Its centres of interest also differed, with the team clearly attributing greater importance to psychosocial support than to technical competence, regard for the role, and information to the practitioner. In conclusion, a survey of this type is a useful and easy way of identifying the aspects that need to be improved on by the palliative care team so as to improve its co-operation with the family physician. But it is of interest only if it forms part of an overall approach whereby, having taken the survey results on board, the team uses them to modify its intervention procedures.

Longitudinal follow-up of TTS-fentanyl use in patients with cancer-related pain: results of a compassionate-use study with special focus on elderly patients

GOALS OF THE WORK

This open compassionate-use prospective registration study evaluated the tolerability, ease of use and applied doses of transdermal (TTS) fentanyl in adult patients with cancer-related pain requiring strong opioid analgesia. Elderly patients were particularly focussed on.

PATIENTS AND METHODS

Previous pain medication was converted to an appropriate dose of TTS-fentanyl. Immediate-release morphine rescue medication was allowed as needed for breakthrough pain. Dose adjustments of TTS-fentanyl, rescue morphine requirements, the ease of use and side-effects were assessed monthly, with special emphasis paid to the severity of constipation and the use of laxatives.

MAIN RESULTS

A total of 663 patients with cancer-related pain, including 8% opioid-naive patients, were enrolled; 661 patients used at least 1 patch of TTS-fentanyl. Of these, 455 subjects were assessed at baseline and at 1 post-baseline visit at least. Individual treatment ranged from a few days to 2 1/2 years; TTS-fentanyl doses ranged from 25 to 950 microg/h. The major reason for study termination was non-drug-related death (61%). Approximately 40% of patients reported constipation. The frequency of constipation depended on the rescue morphine dose used, but no dose-relationship was found for TTS-fentanyl. Patient acceptance of the patches was high; around 85% of patients rated convenience as good to excellent The ease of use and tolerability of TTS-fentanyl in the elderly patients were comparable to that in the total population, except for a slight increase of non-serious adverse events.

CONCLUSIONS

TTS-fentanyl can be applied as long-term therapy to patients with cancer-related pain, including the elderly.

Interleukin-15 redirects the outcome of a tolerizing T-cell stimulus from apoptosis to anergy

Clonal deletion and anergy are 2 mechanisms used by the immune system to establish peripheral tolerance. In vitro, these mechanisms are induced in T lymphocytes by triggering the T-cell receptor (signal 1) in the absence of costimulation (signal 2). T-cell clones have been shown either to become anergic or to die in response to signal 1 alone; yet the factors that govern this choice remain unknown. This study evaluated the influence of the cytokines interleukin (IL)-2 and IL-15 on the response of the Th1 clone hemagglutinin (T-HA) to signal 1, delivered by stimulation with immobilized anti-CD3 monoclonal antibody (mAb). The response induced by immobilized anti-CD3 mAb was dependent on the cytokine milieu; in the presence of IL-2, T-HA cells were subject to apoptosis, whereas in the presence of IL-15 the cells remained viable but showed proliferative unresponsiveness. After release from the anti-CD3 stimulus, the IL-15-rescued T-HA cells regained responsiveness to IL-2 and IL-15 growth factor activity. However, they were unable to proliferate when stimulated with their cognate antigen presented by professional antigen-presenting cells (signal 1 plus 2) and thus had acquired an anergic phenotype. These data assign a novel function to the previously reported antiapoptotic activity of IL-15, namely, the capacity to redirect the T-cell response to partial stimulation from clonal deletion to anergy. Furthermore, they emphasize that the cytokine environment can critically influence the outcome of a tolerizing stimulus.

Tumoral environment triggers transcript anomalies in established tumors: induction of altered gene expression and of aberrant, truncated and B2 repeat-containing gene transcripts

In addition to eugenetic changes, cancerous cells exhibit extensive modifications in the expression levels of a variety of genes. The phenotypic switch observed after inoculation of T lymphoma cells into syngenic mice illustrates the active participation of tumoral environment in the induction of an aberrant gene expression pattern. To further substantiate this contribution, we performed polymerase chain reaction (PCR)-based subtraction suppression hybridization (SSH) to identify genes that are differentially expressed in tumor-derived EL4/13.3 cells compared to the same cells isolated from cultures. Besides a number of unknown genes, the subtracted library contained several known genes that have been reported to be expressed at increased levels in tumors and/or to contribute to carcinogenesis. Apart from clones representing translated transcripts, the subtracted library also contained a high number of clones representing B2 repeat elements, viz. short interspersed repetitive elements that are transcribed by RNA polymerase III. Northern blotting confirmed the induction of B2 transcripts in tumor tissue and also revealed induction of chimeric, B2 repeat-containing mRNA. The appearance of chimeric transcripts was accompanied by aberrant, shorter-than-full-length transcripts, specifically from upregulated genes. Accordingly, in addition to altered gene expression, tumoral environmental triggers constitute a potent mechanism to create an epigenetic diversity in cancers by inducing extensive transcript anomalies.

Palliative care services in Belgium: benefits and shortcomings of a legal framework

All health services dealing with the terminally ill are called upon to dispense palliative care. We shall, however, be making a distinction between palliative care services and other forms of services: in fact, the main activity of a palliative care service is palliative medicine, which is dispensed by its trained and experienced personnel. In Belgium, the first specialist palliative care services developed autonomously, and the absence of a planning policy isolated them from the rest of the health system. The Belgian health authorities decided to put an end to this situation by legislation: the laws introduced determine the number, mission and modus operandi of the various palliative care services, as well as the links to be established between them (interaction of the home care support team and the mobile function in hospitals or institutions for the elderly and association for cooperation). The following is a presentation and critical analysis of this legislation.

Differentiation of EL4 lymphoma cells by tumoral environment is associated with inappropriate expression of the large chondroitin sulfate proteoglycan PG-M and the tumor-associated antigen HTgp-175

Progression to malignancy of transformed cells involves complex genetic alterations and aberrant gene expression patterns. While aberrant gene expression is often caused by alterations in individual genes, the contribution of the tumoral environment to the triggering of this gene expression is less well established. The stable but heterogeneous expression in cultured EL4/13 cells of a novel tumor-associated antigen, designated as HTgp-175, was chosen for the investigation of gene expression during tumor formation. Homogeneously HTgp-175-negative EL4/13 cells, isolated by cell sorting or obtained by subcloning, acquired HTgp-175 expression as a result of tumor formation. The tumorigenicity of HTgp-175-negative vs. HTgp-175-positive EL4 variants was identical, indicating that induction but not selection accounted for the phenotypic switch from HTgp-175-negative to HTgp-175-positive. Although mutagenesis experiments showed that the protein was not essential for tumor establishment, tumor-derived cells showed increased malignancy, linking HTgp-175 expression with genetic changes accompanying tumor progression. This novel gene expression was not an isolated event, since it was accompanied by ectopic expression of the large chondroitin sulfate proteoglycan PG-M and of normal differentiation antigens. We conclude that signals derived from the tumoral microenvironment contribute significantly to the aberrant gene expression pattern of malignant cells, apparently by fortuitous activation of differentiation processes and cause expression of novel differentiation antigens as well as of inappropriate tumor-associated and ectopic antigens.

Cathepsin B-mediated activation of the proinflammatory caspase-11

Members of the caspase (CASP) family of cysteine proteases can be subdivided in proapoptotic caspases and proinflammatory caspases. Whereas the apical activation pathways for the caspases that are involved in the execution of the apoptotic process are beginning to be understood, the pathways that lead to the activation of proinflammatory caspases are still largely unknown. Analysis of subcellular fractions for their ability to process and activate several caspases in vitro led to the identification of lysosomes as the source for a protease that could proteolytically activate the proinflammatory CASP-11. Although this lysosomal activity was sensitive to caspase inhibitors, affinity purification with the biotinylated broad spectrum caspase inhibitor z-VAD.fmk revealed the CASP-11 activating protease as cathepsin B. Activation of CASP-11 by cathepsin B as well as its sensitivity to several caspase inhibitors was further confirmed with purified proteases. Similar to the role of mitochondrial factors in the activation of proapoptotic caspases, our results suggest a potential role for lysosomes and cathepsin B as activators of specific proinflammatory caspases. In addition, the aspecific inhibition of cathepsin B by so-called specific caspase inhibitors implicates that results obtained with these inhibitors should be interpreted with care.

Quiescence-inducing and antiapoptotic activities of IL-15 enhance secondary CD4+ T cell responsiveness to antigen

IL-15 shows functional redundancy with IL-2 due to its usage of the beta and gamma c subunit of the IL-2R. Yet, the requirement of IL-15 for an IL-15R alpha chain for high affinity interaction and the separate cellular sources of IL-2 and IL-15 suggest divergent activities for both cytokines. We compared the growth-inducing and proapoptotic or antiapoptotic activities of IL-15 and IL-2 on mature CD4+ T lymphocytes in the presence or absence of TCR occupancy. We found that the nature of IL-15 activity was critically dependent on the activation status of the T cells. In the absence of TCR triggering, IL-15 did not exert the growth factor activity of IL-2, but induced a quiescent phenotype, characterized by maintenance of the cells in the G0/G1 phase of the cell cycle and down-regulation of CD25, CD71, and CD95 expression. In the presence of appropriate TCR engagement, the IL-15-induced quiescent T cells were resistant against TCR-induced cell death and proliferated strongly. IL-2-treated cells, on the contrary, were sensitized to cell death, resulting in a negative feedback on cellular expansion and weak proliferative responsiveness. Consecutive action of IL-15 during the distinct phases of an in vitro immune response markedly increased the cell output of a second antigenic stimulation, as compared with IL-2. These results imply that during immune reactivity in vivo, IL-15 may take over from the transiently available IL-2 the role of survival factor but not of growth factor, hence promoting the long term maintenance of resting, Ag-experienced CD4+ T cells.

Macrophages induce cellular immunity by activating Th1 cell responses and suppressing Th2 cell responses

Differentiation of naive CD4+ T cells (Th0) into Th1 or Th2 cells determines whether antigen will raise a cellular or a humoral immune response. The maturation pathway chosen by the Th0 cell is often decisive for the outcome of disease and depends among others on the (co-)stimulatory attributes of the APC and the nature and abundance of cytokines provided by the APC and the microenvironment. In this study, we used macrophages, loaded ex vivo with antigen, for inciting Th0 activation and differentiation in vivo. The macrophages were derived from a clonal, immortalized population that both functionally and phenotypically expressed features characteristic of mature macrophages. Injection into syngeneic mice of IFN-gamma-treated, Ag-loaded macrophages induced a primary T cell response, indicated by the occurrence of a proliferative response in vitro after restimulation of splenocytes with Ag. Analysis of the accompanying cytokine secretion revealed high numbers of IFN-gamma-producing Th1 cells and only a few IL-4-secreting Th2 cells. This dominance of Th1 cells had functional implications, reflected in the high titer of Th1 cell-dependent IgG2 Abs and the absence of IgG1, characteristic of humoral immunity. Moreover, administration of Ag-loaded macrophages to mice with an ongoing Th1/Th2 response resulted in a complete suppression of IgG1 production, whereas IgG2 levels remained unaffected. These results demonstrate that macrophages exert APC activity in the organism, strongly skew primary responses to cellular immunity, and in addition suppress an already generated Th2-dependent humoral response, thus characterizing these cells as Th1-oriented APC.