Mixed-mode size-exclusion silica resin for polishing human antibodies in flow-through mode

The polishing step in the downstream processing of therapeutic antibodies removes residual impurities from Protein A eluates. Among the various classes of impurities, antibody fragments are especially challenging to remove due to the broad biomolecular diversity generated by a multitude of fragmentation patterns. The current approach to fragment removal relies on ion exchange or mixed-mode adsorbents operated in bind-and-gradient-elution mode. However, fragments that bear strong similarity to the intact product or whose biophysical features deviate from the ensemble average can elude these adsorbents, and the lack of a chromatographic technology enabling robust antibody polishing is recognized as a major gap in downstream bioprocessing. Responding to this challenge, this study introduces size-exclusion mixed-mode (SEMM) silica resins as a novel chromatographic adsorbent for the capture of antibody fragments irrespective of their biomolecular features. The pore diameter of the silica beads features a narrow distribution and is selected to exclude monomeric antibodies, while allowing their fragments to access the pores where they are captured by the mixed-mode ligands. The static and dynamic binding capacity of the adsorbent ranged respectively between 30-45 and 25-33 gs of antibody fragments per liter of resin. Selected SEMM-silica resins also demonstrated the ability to capture antibody aggregates, which adsorb on the outer layer of the beads. Optimization of the SEMM-silica design and operation conditions - namely, pore size (10 nm) and ligand composition (quaternary amine and alkyl chain) as well as the linear velocity (100 cm/h), ionic strength (5.7 mS/cm), and pH (7) of the mobile phase - afforded a significant reduction of both fragments and aggregates, resulting into a final antibody yield up to 80% and monomeric purity above 97%.

Proceedings of the 2023 Viral Clearance Symposium, Session 3: 2023 VCS New Modalities in Chromatography and Adsorptive Filters

The session provided an update on the application and mechanistic understanding of intensified unit operations (e.g., mixed mode depth filters, mixed mode AEX) since the last conference in 2019. One of the key gaps identified in the 2019 Viral Clearance Symposium session on the topic was for more investigation required to achieve a clear understanding of the molecular mechanisms of virus removal and the relevance of different moleculés interactions including resin, virus, and product. Further investigation into worst-case conditions for these unit operations is also warranted. One of the key outcomes from that 2019 discussion was also that multimodal anion exchangers can have robust and effective virus removal, depending on process and impurities-an observation that was recapitulated with more specific case studies and evidenced by broader application of these chromatographic resins in late-stage regulatory filings.

Proceedings of the 2023 Viral Clearance Symposium: 2023 VCS Summary, Pending Questions, and Next Steps

The 2023 Viral Clearance Symposium (VCS) was hosted by Takeda on 24 and 25 May 2023 in Vienna, Austria. The present conference extended the structure of the previous biennial symposia held between 2009 and 2019. As recapitulated in the introductory session, the genesis of the VCS, as described in the Proceedings of the 2009 VCS was "the worldwide regulatory and industry recognition that challenges, gaps, and opportunities exist, that it formally addressed could benefit the field as whole." This report provides a synopsis of the progress achieved at the conference resulting from detailed technical discussions and the pending questions that still require attention to address. The 2023 VCS was composed of nine individual sessions of short presentations followed by in-depth panel discussions from the presenters. Sessions included Regulatory Updates (with a focus on ICH Q5A(R2) efforts), including a summary of lessons learned from the 2019 VCS, and progress on these key areas mapped into 2023 VCS topics: Viral Clearance Strategy and Case Studies, New Modalities in Chromatography and Adsorptive Filters, Continuous Processing, Viral Clearance Strategy and Process Understanding, Virus Inactivation, Upstream and Downstream Virus Retentive Filtration and Cell Banks, and Advanced Technologies (advanced therapy medicinal products, next-generation sequencing).

Exploring preferred binding domains of IgG1 mAbs to multimodal adsorbents using a combined biophysics and simulation approach

In this work, we employ a recently developed biophysical technique that uses diethylpyrocarbonate (DEPC) covalent labeling and mass spectrometry for the identification of mAb binding patches to two multimodal cation exchange resins at different pH. This approach compares the labeling results obtained in the bound and unbound states to identify residues that are sterically shielded and thus located in the mAb binding domains. The results at pH 6 for one mAb (mAb B) indicated that while the complementarity determining region (CDR) had minimal interactions with both resins, the FC domain was actively involved in binding. In contrast, DEPC/MS data with another mAb (mAb C) indicated that both the CDR and FC domains were actively involved in binding. These results corroborated chromatographic retention data with these two mAbs and their fragments and helped to explain the significantly stronger retention of both the intact mAb C and its Fab fragment. In contrast, labeling results with mAb C at pH 7, indicated that only the CDR played a significant role in resin binding, again corroborating chromatographic data. The binding domains identified from the DEPC/MS experiments were also examined using protein surface hydrophobicity maps obtained using a recently developed sparse sampling molecular dynamics (MD) approach in concert with electrostatic potential maps. These results demonstrate that the DEPC covalent labeling/mass spectrometry technique can provide important information about the domain contributions of multidomain proteins such as monoclonal antibodies when interacting with multimodal resins over a range of pH conditions.

Proceedings of the 2023 Viral Clearance Symposium, Session 6: Viral Inactivation

The use of detergents or low pH hold are commonly employed techniques in biologics downstream processing to inactivate enveloped viruses. These approaches have been demonstrated to be robust and are detailed in ASTM E2888 (low pH) and ASTM E3042-16 (Triton X-100), accordingly. One of the recent challenges is the need for a replacement of Triton X-100 with a more environmentally friendly detergent with similar log10 reduction value (LRV) achieved. The presentations in this session focused on a detailed assessment of a range of detergents. The most well characterized and potentially robust detergents identified were TDAO (n-Tetradecyl-N,N-dimethylamine-N-oxide) and Simulsol SL 11 W. Key performance factors assessed (in direct comparison with the industry standard Triton X-100) were viral inactivation kinetics (total elapsed time to achieve equilibrium), LRV achieved of enveloped viruses, toxicity, potential impact on product quality and process performance, clearance of residual detergent in subsequent downstream steps, assays to support assessment with appropriate limit of quantification, and commercial supply of detergent of the appropriate quality standard. Both TDAO and Simulsol SL11 had similar overall LRV as Triton-100. In addition, for the low pH viral inactivation, reduced LRV was observed at pH > 3.70 and low salt concentration (outside of the ASTM range), which is a cautionary note when applying low pH inactivation to labile proteins.

Insulin purification-Innovation continuum via synthesis of fundamentals, technology, and modeling

Advancement in all disciplines (art, science, education, and engineering) requires a careful balance of disruption and advancement of classical techniques. Often technologies are created with a limited understanding of fundamental principles and are prematurely abandoned. Over time, knowledge improves, new opportunities are identified, and technology is reassessed in a different light leading to a renaissance. Recovery of biological products is currently experiencing such a renaissance. Crystallization is one example of an elegant and ancient technology that has been applied in many fields and was employed to purify insulins from naturally occurring sources. Crystallization can also be utilized to determine protein structures. However, a multitude of parameters can impact protein crystallization and the "hit rate" for identifying protein crystals is relatively low, so much so that the development of a crystallization process is often viewed as a combination of art and science even today. Supplying the worldwide requirement for insulin (and associated variants) requires significant advances in process intensification to support scale of production and to minimize the overall cost to enable broader access. Expanding beyond insulin, the increasing complexity and diversity of biologics agents challenge the current purification methodologies. To harness the full potential of biologics, there is a need to fully explore a broader range of purification technologies, including nonchromatographic approaches. This impetus requires one to challenge and revisit the classical techniques including crystallization, chromatography, and filtration from a different vantage point and with a new set of tools, including molecular modeling. Fortunately, computational biophysics tools now exist to provide insights into mechanisms of protein/ligand interactions and molecular assembly processes (including crystallization) that can be used to support de novo process development. For example, specific regions or motifs of insulins and ligands can be identified and used as targets to support crystallization or purification development. Although the modeling tools have been developed and validated for insulin systems, the same tools can be applied to more complex modalities and to other areas including formulation, where the issue of aggregation and concentration-dependent oligomerization could be mechanistically modeled. This paper will illustrate a case study juxtaposing historical approaches to insulin downstream processes to a recent production process highlighting the application and evolution of technologies. Insulin production from Escherichia coli via inclusion bodies is an elegant example since it incorporates virtually all the unit operations associated with protein production-recovery of cells, lysis, solubilization, refolding, purification, and crystallization. The case study will include an example of an innovative application of existing membrane technology to combine three-unit operations into one, significantly reducing solids handling and buffer consumption. Ironically, a new separations technology was developed over the course of the case study that could further simplify and intensify the downstream process, emphasizing and highlighting the ever-accelerating pace of innovation in downstream processing. Molecular biophysics modeling was also employed to enhance the mechanistic understanding of the crystallization and purification processes.

Towards continuous mAb purification: clearance of host cell proteins from CHO cell culture harvests via "flow-through affinity chromatography" using peptide-based adsorbents

The growth of advanced analytics in manufacturing monoclonal antibodies (mAb) has highlighted the challenges associated with the clearance of host cell proteins (HCPs). Of special concern is the removal of "persistent" HCPs, including immunogenic and mAb-degrading proteins, that co-elute from the Protein A resin and can escape the polishing steps. Responding to this challenge, we introduced an ensemble of peptide ligands that target the HCPs in Chinese hamster ovary (CHO) cell culture fluids and enable mAb purification via flow-through affinity chromatography. This work describes their integration into LigaGuardTM, an affinity adsorbent featuring an equilibrium binding capacity of ~30 mg of HCPs per mL of resin as well as dynamic capacities up to 16 and 22 mg/mL at 1- and 2-minute residence times, respectively. When evaluated against cell culture harvests with different mAb and HCP titers and properties, LigaGuardTM afforded high HCP clearance, with logarithmic removal values (LRVs) up to 1.5, and mAb yield above 90%. Proteomic analysis of the effluents confirmed the removal of high-risk HCPs, including cathepsins, histones, glutathione-S transferase, and lipoprotein lipases. Finally, combining LigaGuardTM for HCP removal with affinity adsorbents for product capture afforded a global mAb yield of 85%, and HCP and DNA LRVs > 4. This article is protected by copyright. All rights reserved.

Proceedings of 2019 Viral Clearance Symposium, Session 4: Viral Clearance Strategy and Process Understanding

The manuscript describes a summary of discussions and outcomes from the 2019 Viral Clearance Symposium Session 4 on the utilization of knowledge, both from within and external to a given organization (ex. across the interdisciplinary space) that support viral clearance strategy and process understanding, including engagement with Health Authorities in the development and implementation. Several significant areas were identified for prioritization in an ICHQ5A update including application of Next Generation Sequencing (NGS) and replacing of in vivo tests., resin reuse, and use of a parvovirus as single model virus for virus filtration. Specific opportunities were identified based on case studies for application of prior knowledge to support risk assessments, to guide viral clearance study designs, and to support viral clearance claims based on a limited number of confirmatory runs. One discussion focused specifically on how to apply best practices and prior knowledge to an assessment of the potential impact of resin reuse on viral clearance. Prior experience showed a trend towards larger LRVs with reused Protein A resin. For other resins, differences in LRV (larger than 1.0) between new and reused resins were mainly found when validation was performed in independent studies, not side by side Another example of applying prior knowledge was an assessment of potential variability and worst case retrovirus-like particle (RVLP) levels in unprocessed bulk presented by from PEI. The opportunity to utilize non-infectious surrogates for viruses (such as RVLPs or parvovirus like particles) in screening experiments to determine the impact of process parameters on viral clearance, and the associated current limitations owing to analytics, was also reviewed.

Highland games: A benchmarking exercise in predicting biophysical and drug properties of monoclonal antibodies from amino acid sequences

Biopharmaceutical product and process development do not yet take advantage of predictive computational modeling to nearly the degree seen in industries based on smaller molecules. To assess and advance progress in this area, spirited coopetition (mutually beneficial collaboration between competitors) was successfully used to motivate industrial scientists to develop, share, and compare data and methods which would normally have remained confidential. The first "Highland Games" competition was held in conjunction with the October 2018 Recovery of Biological Products Conference in Ashville, NC, with the goal of benchmarking and assessment of the ability to predict development-related properties of six antibodies from their amino acid sequences alone. Predictions included purification-influencing properties such as isoelectric point and protein A elution pH, and biophysical properties such as stability and viscosity at very high concentrations. Essential contributions were made by a large variety of individuals, including companies which consented to provide antibody amino acid sequences and test materials, volunteers who undertook the preparation and experimental characterization of these materials, and prediction teams who attempted to predict antibody properties from sequence alone. Best practices were identified and shared, and areas in which the community excels at making predictions were identified, as well as areas presenting opportunities for considerable improvement. Predictions of isoelectric point and protein A elution pH were especially good with all-prediction average errors of 0.2 and 1.6 pH unit, respectively, while predictions of some other properties were notably less good. This manuscript presents the events, methods, and results of the competition, and can serve as a tutorial and as a reference for in-house benchmarking by others. Organizations vary in their policies concerning disclosure of methods, but most managements were very cooperative with the Highland Games exercise, and considerable insight into common and best practices is available from the contributed methods. The accumulated data set will serve as a benchmarking tool for further development of in silico prediction tools.

Formation of Ligand Clusters on Multimodal Chromatographic Surfaces

Multimodal chromatography is a powerful tool which uses multiple modes of interaction, such as charge and hydrophobicity, to purify protein-based therapeutics. In this work, we performed molecular dynamics simulations of a series of multimodal cation-exchange ligands immobilized on a hydrophilic self-assembled monolayer surface at the commercially relevant surface density (1 ligand/nm²). We found that ligands that were flexible and terminated in a hydrophobic group had a propensity to aggregate on the surface, while less flexible ligands containing a hydrophobic group closer to the surface did not aggregate. For aggregating ligands, this resulted in the formation of a surface pattern that contained relatively large patches of hydrophobicity and charge whose sizes exceeded the length scale of the individual ligands. On the other hand, lowering the surface density to 1 ligand/3 nm² reduced or eliminated this aggregation behavior. In addition, the introduction of a flexible linker (corresponding to the commercially available ligand) enhanced cluster formation and allowed aggregation to occur at lower surface densities. Further, the use of flexible linkers enabled hydrophobic groups to collapse to the surface, reducing their accessibility. Finally, we developed an approach for quantifying differences in the observed surface patterns by calculating distributions of the patch size and patch length. This clustering phenomenon is likely to play a key role in governing protein-surface interactions in multimodal chromatography. This new understanding of multimodal surfaces has important implications for developing improved predictive models and designing new classes of multimodal separation materials.

Retrospective Evaluation of Cycled Resin in Viral Clearance Studies-A Multiple Company Collaboration

The BioPhorum Development Group Viral Clearance Workstream performed a collaborative retrospective analysis to evaluate packed bed chromatographic resin performance after repeated cycling for two commonly used chromatography steps in biopharmaceutical manufacturing: protein A and anion exchange. Key variables evaluated in the assessment included virus type, resin type, number of reuse cycles, and virus challenge. In this retrospective analysis of viral clearance data on naïve versus cycled resin, powered by the availability of a decade's worth of accumulated industry data, clearance capability was not negatively impacted by resin cycling. This finding is consistent with publications showing that surrogates for viral clearance capabilities could be employed in lieu of testing the viral clearance of cycled resins for protein A and anion exchange chromatography. The rigorous analysis of the retrospective data supports the view that viral clearance studies for cycled resins are not necessary provided that appropriate cleaning methods are applied during repeated use of the chromatography columns.LAY ABSTRACT: The manufacturing processes for biopharmaceutical products often include reusable chromatographic resins that remove process- and product-related impurities as well as potential contaminating viruses. Typically, chromatography resin is "cycled" through repeated steps of resin conditioning, product purification, and resin cleaning. The cycling approach has been evaluated in both small- and full-scale studies that show the performance parameters are maintained. The ability to remove virus is demonstrated separately in a focused small-scale virus-spiking study that is resource-intensive and costly. This paper is a retrospective review of industry data comparing virus removal by naïve and repeatedly cycled resins that summarizes the viral clearance impact of re-using protein A and anion exchange chromatography resins. The key variables evaluated in the assessment included virus type, resin type, number of cycles, and virus challenge. In this retrospective analysis, it was found that the viral clearance capability is not negatively impacted by resin cycling. This finding is consistent with other publications and supports the view that viral clearance studies for cycled resins are not necessary if appropriate cleaning methods are applied during the repeated use of the chromatography columns.Abbreviations: AAV-2, Adeno-associated virus; A-MuLV, Amphotropic murine leukemia virus; AEX, Anion-exchange chromatography; B/E, Bind and elute; BVDV, Bovine viral diarrhea virus; C.P.G., Controlled pore glass; DEAE, Diethylaminoethanol; EMCV, Encephalomyocarditis virus; FT, Flow through; HAV, Hepatitis A virus; HSV-1, Herpes simplex virus type 1; LOD, Limit of detection; LOQ, Limit of quantification; LRF, Log10 reduction factor; mAb, Monoclonal antibody; MVM, Minute virus of mice; NaOH, Sodium hydroxide; PA, Protein A; PPV, Porcine parvovirus; QA, Quaternary amine; QP, Quaternized polyethyleneimine; qPCR, Quantitative polymerase chain reaction; Reo3, Reovirus type 3; SuHV-1, Suid herpesvirus; SV40, Simian virus 40; X-MuLV, Xenotropic murine leukemia virus.

Proceedings of the 2017 Viral Clearance Symposium, Session 2.2: DSP Unit Operations-Purification Unit Operations

The process capability and potential for various forms of chromatography to remove viruses have been discussed extensively in the literature, including the observed variability in performance of some unit operations such as Protein A and cation exchange (CEX). Some unit operations such as anion exchange (AEX) have shown robustness over a wide range of operating conditions. The robustness and effectiveness of the AEX step combined with a detailed understanding of the mechanisms that result in virus and impurity partitioning versus protein partitioning (e.g. conductivity, loading, pH range) support the feasibility of a generic or modular claim for AEX. A more fundamental understanding of the mechanisms for other chromatographic media (Protein A, CEX, and mixed-mode) could lead to more effective and more robust log reduction value (LRV) claims for these steps as well. Specific examples of CEX and mixed-mode chromatography were explored in the session and were also discussed in detail at the 2013 and 2015 Viral Clearance Symposia. Although some gaps remain in the mechanistic understanding of these unit operations, significant progress has been made and was reported at the 2017 Viral Clearance Symposium. It is important to note that recent publications on the mechanisms of viral clearance for mixed-mode chromatography and a framework for measurement of relative hydrophobicity have provided insights and new tools to better define the operating space and critical process parameters. The session also explored the use of next-generation mixed-mode adsorbers and the potential mechanisms contributing to the observed viral clearance. Gaps were also identified (e.g. integrity test when size-based mechanisms are used) and should be addressed to ensure robust viral clearance for these integrated and productive emerging unit operations.LAY ABSTRACT: Preparative chromatography is the most widely used unit operation for purification of therapeutic proteins. This session focused on the potential for various forms of chromatography to remove viruses. To advance to the next level of process, understanding the virus removal mechanism of different types of chromatography was addressed.

Proceedings of the 2017 Viral Clearance Symposium, Session 6: Ensuring Viral Safety in Continuous Processing

To ensure successful scale-up of continuous processing to large-scale production, it is necessary to seamlessly incorporate viral testing and clearance/inactivation into representative small-scale models. For the first time, a session devoted to the adaptation of standard viral clearance/inactivation unit operations to continuous processing was held at the Viral Clearance Symposium (VCS), with an emphasis on design of valid small-scale models. In this session, the presentations and subsequent discussions identified challenges as well as pathways forward for these emerging technologies. In the first two talks, two different strategies on how to validate continuous low pH viral inactivation (VI) were discussed, focusing on molecule stability and XMuLV inactivation kinetics in the lower residence times of continuous manufacturing, in addition to mathematics-based modeling of continuous viral inactivation processes. The third talk in the session presented a strategy to adapt weak anion exchange chromatography to a continuous manufacturing process by taking advantage of the elution pulses from bind and elute chromatography. The final and fourth talk provided data from novel spiking strategies in consideration of the high, but fluctuating, product titers in the context of continuous flow encountered in continuous manufacturing processes.LAY ABSTRACT: To ensure successful scale-up of continuous processing to large-scale production, it is necessary to seamlessly incorporate viral testing and clearance/inactivation into representative small-scale models.For example, in this session, strategies to validate continuous low pH viral inactivation were discussed.In addition, data from novel spiking strategies in consideration of the high, but fluctuating, product titers in the context of continuous manufacturing processes were presented.

Proceedings of the 2017 Viral Clearance Symposium, Session 2.1: DSP Unit Operations-Virus Filtration/Inactivation

The manufacturing processes of biological medicinal products are expected to be capable of removing and/or inactivating viruses, to primarily provide for adequate safety margins to patients and to thus satisfy the corresponding regulatory expectations. To achieve this goal, process segments specifically dedicated to the task of virus removal or inactivation are designed into manufacturing flows. The state of the art now includes virus removal by nanofiltration, and the more traditional low pH or (solvent-) detergent treatments are used widely, often to provide for two complementary and mechanically different means of virus clearance. Reflective of these process preferences, the virus-filtration/-inactivation session included seven case studies on virus filtration, and one each for a detergent and a low pH treatment.LAY ABSTRACT: To enhance virus clearance capacity, manufacturing processes of therapeutic proteins include process steps dedicated to virus clearance, especially virus-retentive filtration and virus inactivation. This article summarizes the current understanding of process preferences for the said process steps.

Retrospective Evaluation of Low-pH Viral Inactivation and Viral Filtration Data from a Multiple Company Collaboration

Considerable resources are spent within the biopharmaceutical industry to perform viral clearance studies, which are conducted for widely used unit operations that are known to have robust and effective retrovirus clearance capability. The collaborative analysis from the members of the BioPhorum Development Group Viral Clearance Working Team considers two common virus reduction steps in biopharmaceutical processes: low-pH viral inactivation and viral filtration. Analysis included eight parameters for viral inactivation and nine for viral filtration. The extensive data set presented in this paper provides the industry with a reference point for establishing robust processes in addition to other protocols available in the literature (e.g., ASTM Std. E2888-12 for low-pH inactivation). In addition, it identifies points of weakness in the existing data set and instructs the design and interpretation of future studies. Included is an abundance of data that would have been difficult to generate individually but collectively will help support modular viral clearance claims.

Proceedings of the 2009 Viral Clearance Symposium

The 2009 Viral Clearance Symposium (Indianapolis, IN, USA) was held to interactively discuss methods for virus removal and inactivation during biopharmaceutical manufacture. Its origin was the result of worldwide regulatory and industry recognition that challenges, gaps, and opportunities for improvement exist, which if formally addressed could benefit the field as a whole. The symposium began with presentations by the FDA (USA) and the Paul Ehrlich Institute (PEI, Germany), which highlighted viral clearance study information reported in regulatory submissions. In these two presentations, and a subsequent series of brief industry presentations covering various unit operations, it was made clear that many unit operations are quite effective in clearing viruses. This was particularly true of low pH inactivation, anion exchange chromatography, and virus filtration. Moreover, the follow-up discussions at the end of each session, and the wrap-up at the end of the symposium, aimed to synthesize the regulatory data mining knowledge base with the industry-generated data. The symposium also revealed a number of unknowns in the field which were defined and prioritized, and served as potential action items for future experimental studies.

Risk perception, future land use and stewardship: comparison of attitudes about Hanford Site and Idaho National Engineering and Environmental Laboratory

With the ending of the Cold War, the Department of Energy (DOE) is evaluating mission, future land use and stewardship of departmental facilities. This paper compares the environmental concerns and future use preferences of 351 people interviewed at Lewiston, Idaho, about the Hanford Site and Idaho National Engineering and Environmental Laboratory (INEEL), two of DOE's largest sites. Although most subjects lived closer to Hanford than INEEL, most resided in the same state as INEEL. Therefore their economic interests might be more closely allied with INEEL, while their health concerns might be more related to Hanford. Few lived close enough to either site to be directly affected economically. We test the null hypotheses that there are no differences in environmental concerns and future land-use preferences as a function of DOE site, sex, age and education. When asked to list their major concerns about the sites, more people listed human health and safety, and environmental concerns about Hanford compared to INEEL. When asked to list their preferred future land uses, 49% of subjects did not have any for INEEL, whereas only 35% did not know for Hanford. The highest preferred land uses for both sites were as a National Environmental Research Park (NERP), and for camping, hunting, hiking, and fishing. Except for returning the land to the tribes and increased nuclear storage, subjects rated all future uses as more preferred at INEEL than Hanford. Taken together, these data suggest that the people interviewed know more about Hanford, are more concerned about Hanford, rate recreational uses and NERP as their highest preferred land use, and feel that INEEL is more suited for most land uses than Handford. Overall rankings for future land uses were remarkably similar between the sites, indicating that for these stakeholders, DOE lands should be preserved for research and recreation. These preferences should be taken into account when planning for long-term stewardship at these two DOE sites.

Future Land Use and Concerns About the Idaho National Engineering and Environmental Laboratory: A Survey of Urban Dwellers

/ We examined environmental concerns and future land-use preferences of 487 people attending the Boise River Festival in Boise, Idaho, USA, about the Idaho National Engineering and Environmental Laboratory (INEEL), owned by the US Department of Energy (DOE). We were particularly interested in the perceptions of urban dwellers living at some distance from the facility, since attitudes and perceptions are usually examined for people living near such facilities. More than 50% of the people were most worried about contamination and about waste storage and transport, another 23% were concerned about human health and accidents and spills, and the rest listed other concerns such as jobs and the economy or education. When given a list of possible concerns, accidents and spills, storage of current nuclear materials, and storage of additional nuclear materials were rated the highest. Thus both open-ended and structured questions identified nuclear storage and accidents and spills as the most important concerns, even for people living far from a DOE site. The highest rated future land uses were: National Environmental Research Park, recreation (including hiking, camping, fishing and hunting), and returning the land to the Shoshone-Bannock tribes; the lowest rated future land uses were homes and increased nuclear waste storage. These relative rankings are similar to those obtained for other Idahoans living closer to the site and for people living near the Savannah River Site, another DOE facility in South Carolina. The concern expressed about accidents and spills and waste storage translated into a desire not to see additional waste brought to INEEL and a low rating for using INEEL for building homes.KEY WORDS: Future land use; Perceptions; Recreation; Hazardous waste; Department of Energy; Idaho National Engineering and Environmental Laboratory.http://link.springer-ny.com/link/service/journals/00267/bibs/24n4p532.html</HEA

A tyrosine-based signal targets H/K-ATPase to a regulated compartment and is required for the cessation of gastric acid secretion

Gastric acid secretion is mediated by the H/K-ATPase of parietal cells. Activation of acid secretion involves insertion of H/K-ATPase into the parietal cell plasmalemma, while its cessation is associated with reinternalization of the H/K-ATPase into an intracellular storage compartment. The cytoplasmic tail of the H/K-ATPase beta subunit includes a four residue sequence homologous to tyrosine-based endocytosis signals. We generated transgenic mice expressing H/K-ATPase beta subunit in which this motif's tyrosine residue is mutated to alanine. Gastric glands from animals expressing mutant beta subunit constitutively secrete acid and continuously express H/K-ATPase at their cell surfaces. Thus, the beta subunit's tyrosine-based signal is required for the internalization of H/K-ATPase and for the termination of acid secretion. As a consequence of chronic hyperacidity, the mice develop gastric ulcers and a hypertrophic gastropathy resembling Menetrier's disease.