Breaking barriers in antibody discovery: harnessing divergent species for accessing difficult and conserved drug targets

To exploit highly conserved and difficult drug targets, including multipass membrane proteins, monoclonal antibody discovery efforts increasingly rely on the advantages offered by divergent species such as rabbits, camelids, and chickens. Here, we provide an overview of antibody discovery technologies, analyze gaps in therapeutic antibodies that stem from the historic use of mice, and examine opportunities to exploit previously inaccessible targets through discovery now possible in alternate species. We summarize the clinical development of antibodies raised from divergent species, discussing how these animals enable robust immune responses against highly conserved binding sites and yield antibodies capable of penetrating functional pockets via long HCDR3 regions. We also discuss the value of pan-reactive molecules often produced by these hosts, and how these antibodies can be tested in accessible animal models, offering a faster path to clinical development.

Antibody specificity against highly conserved membrane protein Claudin 6 driven by single atomic contact point

The tight junction protein claudin 6 (CLDN6) is differentially expressed on cancer cells with almost no expression in healthy tissue. However, achieving therapeutic MAb specificity for this 4 transmembrane protein is challenging because it is nearly identical to the widely expressed CLDN9, with only 3 extracellular amino acids different. Most other CLDN6 MAbs, including those in clinical development are cross-reactive with CLDN9, and several trials have now been stopped. Here we isolated rare MAbs that bind CLDN6 with up to picomolar affinity and display minimal cross-reactivity with CLDN9, 22 other CLDN family members, or across the human membrane proteome. Amino acid-level epitope mapping distinguished the binding sites of our MAbs from existing clinical-stage MAbs. Atomic-level epitope mapping identified the structural mechanism by which our MAbs differentiate CLDN6 and CLDN9 through steric hindrance at a single molecular contact point, the γ carbon on CLDN6 residue Q156.

Abstract 317: Isolation of highly selective antibodies against claudin 18.2 for the treatment of solid tumors

Monoclonal antibodies (MAbs) are a well-established treatment approach in oncology and other diseases. Nevertheless, many multipass membrane proteins are largely inaccessible as antibody targets due to their poor expression, membrane-dependent structure, small extracellular regions, and high sequence conservation between humans and rodents. Integral Molecular’s MPS Antibody Discovery platform specifically addresses each of these challenges. A key enabling feature of MPS is the use of chickens as an evolutionarily divergent host species for immunization, allowing a more robust immune response for targets that are highly conserved in mammals. We will present on antibodies isolated against challenging membrane protein targets in oncology including Claudin 18.2 (CLDN18.2).CLDN18.2 is a transmembrane adhesion protein undetectable in most adult healthy tissues but highly expressed in gastric, pancreatic, esophageal, and lung cancers. Antibody discovery efforts against this validated target are challenging due to the abundant expression of the splice isoform CLDN18.1 differing by only 8 amino acids in the extracellular domain. As part of the MPS platform, we used virus-like particles (Lipoparticles) to immunize chickens with a high concentration of native CLDN18.2 protein and obtain high-titer immune responses. This enabled us to generate and isolate a large and diverse collection of MAbs (48 unique clones) and select candidates for optimization. We present a panel of three highly specific, humanized CLDN18.2 MAbs with picomolar affinities that are superior to the clinical-stage benchmark. We will show in-depth profiling data for the MAb panel that were used for lead selection and de-risking clinical development. These data include biosensor binding kinetics, amino-acid resolution epitope mapping, and specificity testing against the Membrane Proteome Array (MPA) consisting of 6,000 membrane proteins. This panel of preclinical antibodies are being developed for therapeutic use in various formats, including bispecifics, antibody-drug conjugates, and CAR-T applications.

Citation Format: Brad Screnci, Trevor Barnes, Kristen Shema, Rebecca Rimkunas, Shruthi Kannan, Tim Phillips, Carmen Navia, Charles Azuelos, Tom Charpentier, Jennifer Houtmann, Lisa Miller, Lewis J. Stafford, Benjamin J. Doranz, Joseph B. Rucker, Ross Chambers. Isolation of highly selective antibodies against claudin 18.2 for the treatment of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 317.

Abstract 2892: Development of claudin 6 bispecific antibodies for treatment of ovarian cancer

There is growing interest in applying antibody modalities including bispecifics, antibody-drug conjugates, and CART to solid tumors. However, identifying appropriate tumor-specific targets that avoid adverse effects in healthy tissue has been challenging. The tight junction protein Claudin 6 (CLDN6) is a validated therapeutic target for many solid tumor types, including ovarian, endometrial, testicular, and gastric. It is differentially expressed on cancer cells with no reported expression in normal, healthy tissue. Despite being an attractive target, therapeutic monoclonal antibodies (MAbs) targeting CLDN6 are difficult to discover due to an abundance of closely related family members and an absolute need for high specificity. There are 26 human CLDN family members, and most are broadly expressed and highly conserved. The extracellular region of CLDN6 closely resembles the widely expressed CLDN9 (3 amino acids different). The few CLDN6 MAbs in clinical development have demonstrated significant binding to other CLDN family members and most have now been halted from development. Using Integral Molecular’s MPS antibody discovery platform, we have been able to isolate, and optimize rare antibodies against CLDN6 that do not cross-react with other CLDN family members.

The exquisite specificity of our CLDN6 antibodies makes them amenable to use as the tumor-targeting arm of bispecific T-Cell Engagers. Starting with highly specific CLDN6 antibodies with a range of affinities, we engineered a large set (> 50) of CLDN6xCD3 bispecific antibodies (CLDN6 bispecifics) using multiple formats and CD3 arms that encompass different valencies and geometries. We designed the CLND6 arms to include antibody moieties with different affinities, epitopes, and stoichiometries, as these factors are expected to play a critical role in the potency of these molecules both in in vitro and in vivo. The full panel of bispecifics has been functionally tested in in vitro T cell cytotoxicity assays cells and has demonstrated potent killing of CLDN6-expressing cells with minimal killing of cells expressing other closely related claudin family members. We have also extensively characterized this panel of bispecific antibodies for detailed binding to both CD3 and CLDN6, selectivity against closely related claudin family members, and developability. The bispecifics were also screened for specificity against ~6,000 membrane proteins, representing > 95% of the entire human membrane proteome.

Solid tumors lead to 580,000 deaths annually in the US, and safe and effective therapeutics for many late-stage solid tumors are lacking. Ovarian cancer alone kills 14,000 people each year, and many patients do not respond to currently available treatments. The exquisite specificity of our CLDN6xCD3 bispecifics suggests their potential to address the need for potent therapeutic modalities for ovarian and other cancers without compromising patient safety.

Citation Format: Joseph Rucker, Kyle Doolan, Breanna Tyrell, Anna Lobley, Nick Molino, Kristen Shema, Kyle Guldner, Alyssa Cunningham, Ross Chambers, Riley Payne. Development of claudin 6 bispecific antibodies for treatment of ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2892.

Sites of vulnerability in HCV E1E2 identified by comprehensive functional screening

The E1 and E2 envelope proteins of hepatitis C virus (HCV) form a heterodimer that drives virus-host membrane fusion. Here, we analyze the role of each amino acid in E1E2 function, expressing 545 individual alanine mutants of E1E2 in human cells, incorporating them into infectious viral pseudoparticles, and testing them against 37 different monoclonal antibodies (MAbs) to ascertain full-length translation, folding, heterodimer assembly, CD81 binding, viral pseudoparticle incorporation, and infectivity. We propose a model describing the role of each critical residue in E1E2 functionality and use it to examine how MAbs neutralize infection by exploiting functionally critical sites of vulnerability on E1E2. Our results suggest that E1E2 is a surprisingly fragile protein complex where even a single alanine mutation at 92% of positions disrupts its function. The amino-acid-level targets identified are highly conserved and functionally critical and can be exploited for improved therapies and vaccines.

Self-reported mindfulness, cyclist anger and aggression

Anger is a common behaviour exhibited by road users when one's goals are perceived to have been blocked by another. Recent research has demonstrated that, generally, cyclists tend to deal with anger in constructive ways. However, when anger does manifest, it can result in behaviours that increase their crash risk. Amongst motor vehicle drivers, mindfulness levels have been associated with less anger and appear to mediate anger and associated aggression. The current study sought to understand whether mindfulness has similar associations with anger and aggression in a sample of cyclists. A total of 583 cyclists (males = 68 %) completed an online questionnaire that sought information on their levels of mindfulness, current mindfulness practices and tendencies for anger and aggression while cycling. The relationships between these were then examined using structural equation modelling. The results showed that cyclists with higher mindfulness levels tended to report less anger across a range of situations (e.g., interactions with pedestrians, cyclists, motor vehicle drivers and police). Both direct and indirect (through anger) relationships were found between mindfulness and aggression, again showing that more mindful cyclists tended to engage in less frequent aggression. These findings align with recent research investigating this relationship amongst motor vehicle drivers and suggest that mindfulness may be a promising strategy to reduce or avoid anger and aggression in cyclists.

Abstract 527: Isolation of large and diverse monoclonal antibody panels against the multipass membrane protein targets Kv1.3, P2X7, and Claudin 18.2

Monoclonal antibodies (MAbs) are a well-established treatment approach in oncology and other diseases. Nevertheless, multipass membrane proteins are largely inaccessible as MAb targets due to their poor expression, membrane-dependent structure, small extracellular regions, and high sequence conservation between humans and rodents. Integral Molecular's MPS Antibody Discovery platform specifically addresses each of these challenges. Using this platform, we have isolated large and diverse panels of functional (agonist/antagonist) MAbs against targets including Claudin 18.2 and the ion channels P2X7 and Kv1.3. A key feature that enables the success of the platform is the use of divergent species for immunization. Chickens are immunized with a combination of DNA and Lipoparticles (high-concentration membrane proteins) to obtain high-titer immune responses against the native membrane protein. Our optimized phage-display protocols allow the isolation of large panels of MAbs against diverse epitopes. The MPS Antibody Discovery platform offers the potential for discovering MAbs against difficult targets in cancer with a success rate over 95%.

Citation Format: Lewis J. Stafford, Sharon Willis, Joseph Rucker, Benjamin Doranz, Ross Chambers. Isolation of large and diverse monoclonal antibody panels against the multipass membrane protein targets Kv1.3, P2X7, and Claudin 18.2 [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 527.

Enhancing social functioning in young people at Ultra High Risk (UHR) for psychosis: A pilot study of a novel strengths and mindfulness-based online social therapy

BACKGROUND

Psychological and pharmacological treatments have been shown to reduce rates of transition to psychosis in Ultra High Risk (UHR) young people. However, social functioning deficits have been unresponsive to current treatments.

AIMS

The study aims were to: i) describe the theoretical basis and therapeutic targets of a novel intervention targeting social functioning in UHR young people; and ii) examine its acceptability, safety and preliminary effect on social functioning.

METHODS

An international, multidisciplinary team developed a new intervention (MOMENTUM) to improve social functioning in UHR young people. MOMENTUM blends two novel approaches to social recovery: strengths and mindfulness-based intervention embedded within a social media environment, and application of the self-determination theory of motivation. The acceptability and safety of MOMENTUM were tested through a 2-month pilot study with 14 UHR participants.

RESULTS

System usage was high, with over 70% of users being actively engaged over the trial. All participants reported a positive experience using MOMENTUM, considered it safe and would recommend it to others. 93% reported it to be helpful. There were large, reliable improvements in social functioning (d = 1.83, p < 0.001) and subjective wellbeing (d = 0.75, p = 0.03) at follow-up. There were significant increases in the mechanisms targeted by the intervention including strengths usage (d = 0.70, p = 0.03), mindfulness skills (d = 0.66, p = 0.04) and components of social support. Social functioning improvement was significantly correlated with indicators of system usage.

CONCLUSION

MOMENTUM is engaging and safe. MOMENTUM appeared to engage the hypothesized mechanisms and showed promise as a new avenue to improve social functioning in UHR young people.

Abstract 5759: Discovery of a novel claudin 6 (CLDN6) specific monoclonal antibody

Claudin 6 (CLDN6) is a tight junction molecule that is involved in cell to cell adhesion of epithelial and endothelial cell sheets. CLDN6 is considered an oncofetal protein which is not expressed in normal human tissue but is expressed in some cancers such as endometrial, ovarian and testis cancer. Expression of CLDN6 in endometrial and urothelial cancer leads to a poor prognosis. The problem of developing antibodies against CLDN6 is that the family member claudin 9 (CLDN9) is highly homologous, only varying by 2 amino acids in the extracellular domain. To address this need, Integral Molecular has developed the MPS Discovery Engine® to enable the isolation, characterization, and engineering of monoclonal antibodies for tight junction proteins, GPCRs, ion channels, and transporters. MPS utilizes a collection of technologies to address each of the barriers to monoclonal antibody development against the native extracellular epitopes of multispan membrane proteins. These include, antigen engineering to attain high levels of surface expression, DNA and Lipoparticle immunization to present native epitopes to the immune system, diverse immunization host species to deal with highly conserved proteins, Lipoparticles (high concentration native membrane proteins) to enable phage display, microfludic B-cell isolation to isolate rare MAbs, and shotgun mutagenesis (comprehensive alanine scanning) for epitope mapping. Using the MPS Discovery Engine® we were able to successfully screen a large panel of clones for claudin 6 specificity. From these clones there were 72 potential antibodies that reacted with either claudin 6 or 6/9. A subset of these antibodies reacted only to claudin 6 and not to claudin 9 which has led to our lead drug candidate. With our MPS Discovery Engine® platform, we have the ability to target intact, conformationally specific, and functional antibodies to multipass membrane proteins.

Citation Format: Lewis J. Stafford, Brad Screnci, Chidananda Sulli, Erin Rosenberg, Nicholas Molino, David Tucker, Jonathan Sullivan, Trevor Barnes, Jennifer Pfaff, Tanmayee Hazarika, Thomas Charpentier, Samantha Gilman, Rebecca Rimkunas, Rona Wilf, Sharon Willis, Benjamin Doranz, Joseph Rucker, Ross Chambers. Discovery of a novel claudin 6 (CLDN6) specific monoclonal antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5759.

Abstract 74: Discovery of new therapeutic monoclonal antibodies to challenging GPCRs, ion channels and transporters

The objective of this work was to evaluate the ability to generate panels of monoclonal antibodies against a set of highly challenging targets including GPCRs (CB1, C5AR, CXCR5 and CGRPR), transporters (GLUT4), and ion channels (P2X3). Integral membrane proteins are important drug targets and monoclonal antibodies (MAbs) directed against them are highly sought for therapeutic purposes. However, the complex structure of multispan membrane protein targets makes the discovery of these MAbs especially challenging. To address this need, Integral Molecular has developed the MPS Discovery Engine® to enable the isolation, characterization, and engineering of monoclonal antibodies for GPCRs, ion channels, and transporters. MPS utilizes a collection of technologies to address each of the barriers to monoclonal antibody development against the native extracellular epitopes of multispan membrane proteins. These include, antigen engineering to attain high levels of surface expression, DNA and Lipoparticle immunization to present native epitopes to the immune system, diverse immunization host species to deal with highly conserved proteins, Lipoparticles (high concentration native membrane proteins) to enable phage display and microfludic B-cell isolation, and shotgun mutagenesis (comprehensive Alanine scanning) for epitope mapping. Using the MPS Discovery Engine® we were able to successfully generate large panels of antibodies to the targets that were able to bind to the native extracellular epitopes on cells by flow cytometry. A subset of the antibodies had antagonist activity. With this technology we have the ability to target intact, conformation specific, and functional antibodies to complex membrane proteins.

Citation Format: Lewis J. Stafford, Ross Chambers, Sharon H. Willis, Moniquetta Hall, Brad Screnci, Manu Mabila, David Tucker, Trevor Barnes, Rachel Fong, Andrew Ettenger, Jennifer Pfaff, Chidananda Sulli, Nicholas Molino, Andrew Hudacek, Benjamin J. Doranz, Joseph Rucker. Discovery of new therapeutic monoclonal antibodies to challenging GPCRs, ion channels and transporters [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 74. doi:10.1158/1538-7445.AM2017-74

Abstract 3386: The development of a highly specific monoclonal antibody against Ki67 useful for immunohistochemistry

Ki-67 is a nuclear protein that is a useful marker of proliferation. Ki-67 antibodies are used to generate a Ki-67 labeling index, which is the percentage of cells with nuclear immunostaining in immunohistochemistry. The Ki-67 labeling index may be useful as a prognostic and predictive marker in cancer. The Ki-67 labeling index relies on the use of antibodies with a suitable level of sensitivity and specificity, and many Ki-67 antibodies have been developed over the last two decades. One of the most widely used Ki-67 antibodies is the mouse monoclonal MIB1. However, there have been many reports showing that in some cases MIB1 detects an unexpected membranous and cytoplasmic staining pattern in immunohistochemistry. Since Ki-67 is exclusively expressed in the nucleus this raises questions about the specificity of MIB1. We have created a nearly comprehensive microarray of about 17,000 human proteins to investigate the specificity of MIB1 and identify cross reacting proteins. The protein microarray was also used to screen new panels of mouse monoclonals against Ki-67. We have identified the antibody UMAB107 that in immunohistochemistry performs with similar sensitivity as MIB1, but unlike MIB1, UMAB107 is highly specific.

Citation Format: Caiwei Chen, Kehu Yuan, Boyang Chu, Youmin Shu, Jian Chen, Joe Stafford, Wei Fu, Wei-Wu He, Ross Chambers, Donghui Ma. The development of a highly specific monoclonal antibody against Ki67 useful for immunohistochemistry. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3386. doi:10.1158/1538-7445.AM2015-3386

Pan-European early switch/early discharge opportunities exist for hospitalized patients with methicillin-resistant Staphylococcus aureus complicated skin and soft tissue infections

The objective of this study was to document pan-European real-world treatment patterns and healthcare resource use and estimate opportunities for early switch (ES) from intravenous (IV) to oral antibiotics and early discharge (ED) in hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA) complicated skin and soft tissue infections (cSSTIs). This retrospective observational medical chart review study enrolled 342 physicians across 12 European countries who collected data from 1542 patients with documented MRSA cSSTI who were hospitalized (July 2010 to June 2011) and discharged alive (by July 2011). Data included clinical characteristics and outcomes, hospital length of stay (LOS), MRSA-targeted IV and oral antibiotic use, and ES and ED eligibility according to literature-based and expert-validated criteria. The most frequent initial MRSA-active antibiotics were vancomycin (50.2%), linezolid (15.1%), clindamycin (10.8%), and teicoplanin (10.4%). Patients discharged with MRSA-active antibiotics (n = 480) were most frequently prescribed linezolid (42.1%) and clindamycin (19.8%). IV treatment duration (9.3 ± 6.5 vs. 14.6 ± 9.9 days; p <0.001) and hospital LOS (19.1 ± 12.9 vs. 21.0 ± 18.2 days; p 0.162) tended to be shorter for patients switched from IV to oral treatment than for patients who received IV treatment only. Of the patients, 33.6% met ES criteria and could have discontinued IV treatment 6.0 ± 5.5 days earlier, and 37.9% met ED criteria and could have been discharged 6.2 ± 8.2 days earlier. More than one-third of European patients hospitalized for MRSA cSSTI could be eligible for ES and ED, resulting in substantial reductions in IV days and bed-days, with potential savings of €2000 per ED-eligible patient.

Costs of adverse events among patients with HIV infection treated with nonnucleoside reverse transcriptase inhibitors

OBJECTIVES

The aim of the study was to assess the incidence and costs of adverse events (AEs) among patients with HIV infection treated with nonnucleoside reverse transcriptase inhibitors (NNRTIs) from the health care system perspective.

METHODS

US medical and pharmacy claims during 2004-2009 were examined to select adult new NNRTI users with HIV infection. The incidence of selected AEs and time to occurrence were assessed during the first year. Episodes of care for each AE were identified using claims associated with AE management. For each AE, a propensity score model was used to match patients with an AE to those without (1:4) based on the propensity of having an AE. Mean total health care costs, AE-associated costs and incremental costs per episode, and annual total health care costs per patient were calculated.

RESULTS

Of the 2548 NNRTI-treated patients, 29.3% experienced AEs. The incidence ranged from 0.4 episodes/1000 person-years for suicide/self-injury to 14.9 episodes/1000 person-years for dizziness, 49.8 episodes/1000 person-years for depression and 150.3 episodes/1000 person-years for lipid disorder. The mean AE-associated cost (duration) per episode ranged from $586 (88 days) for lipid disorder to $975 (33 days) for rash, $2760 (73 days) for sleep-related symptoms and $4434 (41 days) for nausea/vomiting. The mean incremental cost per episode ranged from $1580 for rash to $2032 for lipid disorder, $8307 for sleep-related symptoms and $12 833 for nausea/vomiting. During the 12 months following NNRTI initiation, the mean annual total health care cost was $27 299 (efavirenz: $26 185; other NNRTIs: $34 993) and AE-associated costs were $608 (efavirenz: $554; other NNRTIs: $979) among all NNRTI users.

CONCLUSIONS

With treatment increasing patient survival, comparisons of therapeutic regimens should consider treatment-associated AEs. Findings from this study could be informative for clinicians and payers in managing HIV infection with NNRTIs.

Snorkel: an epitope tagging system for measuring the surface expression of membrane proteins

Tags are widely used to monitor a protein’s expression level, interactions, protein trafficking, and localization. Membrane proteins are often tagged in their extracellular domains to allow discrimination between protein in the plasma membrane from that in internal pools. Multipass membrane proteins offer special challenges for inserting a tag since the extracellular regions are often composed of small loops and thus inserting an epitope tag risks perturbing the structure, function, or location of the membrane protein. We have developed a novel tagging system called snorkel where a transmembrane domain followed by a tag is appended to the cytoplasmic C-terminus of the membrane protein. In this way the tag is displayed extracellularly, but structurally separate from the membrane protein. We have tested the snorkel tag system on a diverse panel of membrane proteins including GPCRs and ion channels and demonstrated that it reliably allows for monitoring of the surface expression.

Monoclonal antibodies to transmembrane proteins (P4022)

Transmembrane proteins, including multipass transmembrane proteins like GPCRs and ion channels, are important targets for therapeutic monoclonal antibody (mab) discovery. Therapeutic antibodies to this class of proteins are generally targeted to extracellular domains displayed on the surfaces of living cells. Challenges associated with developing antibodies to this class of targets are small numbers of extracellular amino acids, membrane-dependent protein conformation, difficulty in expression at high levels, high amino acid sequence homology of human and mouse proteins, and post-translational modifications. DNA immunization strategies with full-length constructs and high throughput flow cytometry screening of mab binding to transfected and control cells was used to generate and identify large numbers of mabs to CXCR4 and ADORA2A (GPCRs) and CD20. Panels of mabs were generated for all 3 targets with low numbers of hybridoma fusions. For each target the mab gene sequences were shown to be unique and contain levels of somatic hypermutation comparable to existing benchmark therapeutic antibodies. Functional assays including apoptosis and receptor modulation (calcium flux and cAMP modulation) further demonstrated that the technical approach generated diverse panels of antibodies that exhibit functional activity as good or better than existing benchmark therapeutic antibodies.

Abstract 4325: Monoclonal antibodies to transmembrane proteins

Transmembrane proteins, including multipass transmembrane proteins like GPCRs and ion channels, are important targets for therapeutic monoclonal antibody (mab) discovery. Therapeutic antibodies to this class of proteins are generally targeted to extracellular domains displayed on the surfaces of living cells. Challenges associated with developing antibodies to this class of targets are small numbers of extracellular amino acids, membrane-dependent protein conformation, difficulty in expression at high levels, high amino acid sequence homology of human and mouse proteins, and post-translational modifications. DNA immunization strategies with full-length constructs and high throughput flow cytometry screening of mab binding to transfected and control cells was used to generate and identify large numbers of mabs to CXCR4 and ADORA2A (GPCRs) and CD20 (a tetraspan membrane protein). Panels of mabs were generated for all 3 targets with low numbers of hybridoma fusions. For each target the mab gene sequences were shown to be unique and contain levels of somatic hypermutation comparable to existing benchmark therapeutic antibodies. Epitope mapping with mutant proteins identified diverse patterns of reactivity including known and novel specificities. Functional assays including apoptosis and receptor modulation (calcium flux and cAMP modulation) further demonstrated that the technical approach generated diverse panels of antibodies that exhibit functional activity as good or better than existing benchmark therapeutic antibodies

Citation Format: Michael C. Brown, Ross Chambers, Dale V. Onisk, Tony R. Joaquim, Lewis J. Stafford, Klaus Lindpaintner, Daniel Keter, James W. Stave. Monoclonal antibodies to transmembrane proteins. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4325. doi:10.1158/1538-7445.AM2013-4325

Healthcare professionals' knowledge of calories

AIM

To determine healthcare professionals' knowledge of the calorie content of foods and the relationship to weight maintenance.

METHOD

A cross-sectional questionnaire was used to survey 179 clinical staff, non-clinical staff and life coaches working in health care.

RESULTS

The response rate is 81%. The majority of respondents identified the weight loss requirements necessary to achieve marked health benefits in obese patients. Estimation of calorie and salt contents of specified foods was generally inaccurate. The majority of healthcare professionals did not know the amount of exercise required to burn off the calories of commonly consumed foods.

CONCLUSION

Support and education are required for healthcare professionals to manage the challenges associated with obesity.

The surgical aspects of Role 2 Afloat

The current configuration of the surgical component of the Role 2 Afloat team is described, including an outline of the equipment available. The lessons learned from a recent exercise, where a Role 2 Afloat team was deployed on RFA CARDIGAN BAY are outlined and expanded, emphasising the difficulties of providing damage control surgery in the maritime environment.

Impact of immunization technology and assay application on antibody performance--a systematic comparative evaluation

Antibodies are quintessential affinity reagents for the investigation and determination of a protein's expression patterns, localization, quantitation, modifications, purification, and functional understanding. Antibodies are typically used in techniques such as Western blot, immunohistochemistry (IHC), and enzyme-linked immunosorbent assays (ELISA), among others. The methods employed to generate antibodies can have a profound impact on their success in any of these applications. We raised antibodies against 10 serum proteins using 3 immunization methods: peptide antigens (3 per protein), DNA prime/protein fragment-boost ("DNA immunization"; 3 per protein), and full length protein. Antibodies thus generated were systematically evaluated using several different assay technologies (ELISA, IHC, and Western blot). Antibodies raised against peptides worked predominantly in applications where the target protein was denatured (57% success in Western blot, 66% success in immunohistochemistry), although 37% of the antibodies thus generated did not work in any of these applications. In contrast, antibodies produced by DNA immunization performed well against both denatured and native targets with a high level of success: 93% success in Western blots, 100% success in immunohistochemistry, and 79% success in ELISA. Importantly, success in one assay method was not predictive of success in another. Immunization with full length protein consistently yielded the best results; however, this method is not typically available for new targets, due to the difficulty of generating full length protein. We conclude that DNA immunization strategies which are not encumbered by the limitations of efficacy (peptides) or requirements for full length proteins can be quite successful, particularly when multiple constructs for each protein are used.

INTRACELLULAR OXIDATION-REDUCTION STUDIES : I. REDUCTION POTENTIALS OF AMOEBA DUBIA BY MICRO INJECTION OF INDICATORS

Twenty-five oxidation-reduction indicators were injected in oxidized or reduced form into Amoeba dubia and Amœba proteus under controlled conditions of oxygen access. (1) Under anaerobiosis the ameba was able to reduce completely all the reversible oxidation-reduction indicators down to and including indigo disulfonate. (2) Under anaerobiosis the ameba was unable to reoxidize six of the most easily oxidizable indicators. (3) Under aerobiosis the ameba was able to reduce completely all the indicators down to and including 1-naphthol-2-sulfonate indo-2, 6-dichlorophenol. Toluylene blue, methylene blue and indigo tetrasulfonate were sometimes completely and sometimes only partly reduced, depending on the quantity of indicator injected and the duration of observation. (4) The time of reduction varied approximately with the size of the injection. Reduction was more rapid under anaerobiosis than under aerobiosis, more rapid in active than in sluggish cells and was retarded by toxic compounds. (5) Sulfonated compounds were somewhat toxic, as a rule. In interpreting reduction phenomena of micro injection, it is necessary to take into consideration the intensity, capacity and rate factors. It then becomes apparent that the ameba has a high reducing potential lying on the rH scale below the zone of indigo disulfonate. The reducing capacity of the ameba seems to be relatively great in the region of the simple indophenols and of a progressively diminishing magnitude as the zone of the indigos is approached. Material of high reduction potential appears to be generated within the ameba at a measurable rate. These phenomena, observed in the interior of the cell with the aid of indicators, parallel very closely those found in reduction electrode studies on bacterial cultures.

MICRURGICAL STUDIES IN CELL PHYSIOLOGY : III. THE ACTION OF CO(2)AND SOME SALTS OF NA, CA, AND K ON THE PROTOPLASM OF AMOEBA DUBIA

I. Plasmalemma. 1. Of the salts used in these experiments the anions have only a modifying effect on the cations. The dispersive action of Na and, to a lesser extent, of K, predominates. Borate increases the toxicity of Na and acetate decreases it. 2. CO₂ and carbonates dissolve the plasmalemma readily. 3. Na lactate tends to dissolve the surface especially when brought into contact with it from the interior by injection. Lactate antagonizes the stimulating effect of Ca on the plasmalemma. II. The Internal Protoplasm. 4. Acid phosphate of Na and K, when injected, causes a membrane to form around the granular endoplasm within the ameba. 5. Na borate increases the toxicity of Na inside the cell. 6. Bubbles of CO₂, injected into the cell, cause an increase of fluidity of the internal protoplasm. These bubbles shrink and disappear from the cell more readily than air bubbles. 7. The anions modify the typical cation effect. Carbonates accentuate the liquefying and solvent action of Na. Phosphates prevent a complete rounding of the ameba caused by Na. Lactate inhibits the solidification and pinching off effect caused by Ca. III. Physiological Significance of Salts. 8. The buffer salts can be injected in high concentrations without toxic effects but amebæ can be immersed in them only in very dilute solutions without injury. 9. The inhibiting action of lactate and the dispersive effect of CO₂, carbonates, and lactate on the plasma membrane, must be of importance in a consideration of the functions of the organism and perhaps in the production of pathological changes.

MICRURGICAL STUDIES IN CELL PHYSIOLOGY : I. THE ACTION OF THE CHLORIDES OF NA, K, CA, AND MG ON THE PROTOPLASM OF AMOEBA PROTEUS

By means of micro-dissection and injection Amoeba proteus was treated with the chlorides of Na, K, Ca, and Mg alone, in combination, and with variations of pH. I. The Plasmalemma. 1. NaCl weakens and disrupts the surface membrane of the ameba. Tearing the membrane accelerates the disruption which spreads rapidly from the site of the tear. KCl has no disruptive effect on the membrane but renders it adhesive. 2. MgCl(2) and CaCl(2) have no appreciable effect on the integrity of the surface membrane of the ameba when applied on the outside. No spread of disruption occurs when the membrane is torn in these salts. When these salts are introduced into the ameba they render the pellicle of the involved region rigid. II. The Internal Protoplasm. 3. Injected water either diffuses through the protoplasm or becomes localized in a hyaline blister. Large amounts when rapidly injected produce a "rushing effect". 4. HCl at pH 1.8 solidifies the internal protoplasm and at pH 2.2 causes solidification only after several successive injections. The effect of the subsequent injections may be due to the neutralization of the cell-buffers by the first injection. 5. NaCl and KCl increase the fluidity of the internal protoplasm and induce quiescence. 6. CaCl(2) and MgCl(2) to a lesser extent solidify the internal protoplasm. With CaCl(2) the solidification tends to be localized. With MgCl(2) it tends to spread. The injection of CaCl(2) accelerates movement in the regions not solidified whereas the injection of MgCl(2) induces quiescence. III. Pinching-Off Reaction. 7. A hyaline blister produced by the injection of water may be pinched off. The pinched-off blister is a liquid sphere surrounded by a pellicle. 8. Pinching off always takes place with injections of HCl when the injected region is solidified. 9. The injection of CaCl(2) usually results in the pinching off of the portion solidified. The rate of pinching off varies with the concentration of the salt. The injection of MgCl(2) does not cause pinching off. IV. Reparability of Torn Surfaces. 10. The repair of a torn surface takes place readily in distilled water. In the different salt solutions, reparability varies specifically with each salt, with the concentration of the salt, and with the extent of the tear. In NaCl and in KCl repair occurs less readily than in water. In MgCl(2) repair takes place with great difficulty. In CaCl(2) a proper estimate of the process of repair is complicated by the pinching-off phenomenon. However, CaCl(2) is the only salt found to increase the mobility of the plasmalemma, and this presumably enhances its reparability. 11. The repair of the surface is probably a function of the internal protoplasm and depends upon an interaction of the protoplasm with the surrounding medium. V. Permeability. 12. NaCl and KCl readily penetrate the ameba from the exterior. CaCl(2) and MgCl(2) do not. 13. All four salts when injected into an ameba readily diffuse through the internal protoplasm. In the case of CaCl(2) the diffusion may be arrested by the pinching-off process. VI. Toxicity. 14. NaCl and KCl are more toxic to the exterior of the cell than to the interior, and the reverse is true for CaCl(2) and MgCl(2). 15. The relative non-toxicity of injected NaCl to the interior of the ameba is not necessarily due to its diffusion outward from the cell. 16. HCl is much more toxic to the exterior of a cell than to the interior; at pH 5.5 it is toxic to the surface whereas at pH 2.5 it is not toxic to the interior. NaOH to pH 9.8 is not toxic either to the surface or to the interior. VII. Antagonism. 17. The toxic effects of NaCl and of KCl on the exterior of the cell can be antagonized by CaCl(2) and this antagonism occurs at the surface. Although the lethal effect of NaCl is thus antagonized, NaCl still penetrates but at a slower rate than if the ameba were immersed in a solution of this salt alone. 18. NaCl and HCl are mutually antagonistic in the interior of the ameba. No antagonism between the salts and HCl was found on the exterior of the ameba. No antagonism between the salts and NaOH was found on the interior or exterior of the ameba. 19. The pinching-off phenomenon can be antagonized by NaCl or by KCl, and the rate of the retardation of the pinching-off process varies with the concentration of the antagonizing salt. 20. The prevention of repair of a torn membrane by toxic solutions of NaCl or KCl can be antagonized by CaCl(2). These experiments show directly the marked difference between the interior and the exterior of the cell in their behavior toward the chlorides of Na, K, Ca, and Mg.

MICRURGICAL STUDIES IN CELL PHYSIOLOGY : IV. COLORIMETRIC DETERMINATION OF THE NUCLEAR AND CYTOPLASMIC pH IN THE STARFISH EGG

I. Cytoplasm. 1. The normal cytoplasmic pH, colorimetrically determined, of the starfish eggs in the unfertilized, fertilized, and first and second cleavage stages is 6.7 ± 0.1. 2. Cytolysis lowers the pH to a value 5.5 ± 0.1. 3. The cytolyzed material in time assumes the pH of its environing sea water. 4. The acid due to mechanical injury can also be detected in the environment of the egg. 5. Injury to the cytoplasm unaccompanied by visible disintegration causes an increase in acidity which is quickly neutralized. II. Germinal Vesicle. 6. The intranuclear pH, colorimetrically determined, of the immature Asterias egg is 7.5 ± 0.1. 7. Injury to the nucleus does not change its pH. 8. The spherical nuclear remnant which persists after injury gradually assumes the pH of its environment. III. Plasmalemma. 9. A dye to which the cell is normally impermeable can penetrate through a tear in the surface from an environment more acid than normal. This may be due to a difference in the formation of the plasmalemma in a normal and an acid medium.

A MICRO INJECTION STUDY ON THE PERMEABILITY OF THE STARFISH EGG

The experiments with the NH(4)Cl are similar to, and corroborate micro injection experiments performed in connection with some work on mustard gas in which the writer collaborated. Eggs immersed in sea water containing decomposed mustard gas, at a certain low concentration are not affected. If, however, the solution be injected, the egg quickly cytolyzes owing to the free HCl present. A similar impermeability of the protoplasmic surface film to certain substances was also encountered in injection work on Amoeba. Amoeboe immersed in an aqueous solution of eosin will not take the stain till after death. On the other hand, the eosin, when injected into the Amoeba, quickly permeates the protoplasm, to be arrested only at the surface. The semipermeability of a living cell appears primarily to be a function of its surface film. It is immaterial whether this film be that of the original cortex of the cell, a film newly formed over a cut surface, or a film that surrounds an artificially induced vacuole within the cell. As long as such a surface film exists neither the acid group of the NH(4)Cl nor the alkaline group of the NaHCO(3) can, within certain concentration limits, penetrate the protoplasm. These solutions, if injected beneath the surface film, however, will produce their characteristic effects upon the protoplasm.

CHANGES IN PROTOPLASMIC CONSISTENCY AND THEIR RELATION TO CELL DIVISION

1. The development of the amphiaster is associated with the formation of two semisolid masses within the more fluid egg substance. 2. The elongation of the egg during cleavage is possibly produced as a consequence of the mutual pressure of these two growing semisolid masses. 3. The division of the egg into two blastomeres consists essentially in a growth, within the egg, of two masses of material at the expense of the surrounding cytoplasm. When all the cytoplasm of the egg is incorporated in these two masses cleavage occurs. 4. After a certain period of time the semisolid masses revert to a more fluid state. In the eggs studied this normally occurs after the cleavage furrow has completed the separation of the two blastomeres. The formation of the furrow, however, may be prevented in various ways, upon which the egg reverts to a single spherical semifluid mass containing two nuclei. 5. An egg mutilated during its semisolid state (amphiaster stage) may or may not revert to a more fluid state. If the more solid state is maintained, the cleavage furrow persists and proceeds till cleavage is completed. If the mutilation causes the egg to revert to the more fluid state the furrow becomes obliterated and a new cleavage plane is subsequently adopted. 6. The nuclei of eggs in the semifluid state are able to alter their positions. In semifluid mutilated eggs the nuclei tend to move to positions which may assure symmetry in aster formation and cleavage.

Novel Objective Biomarkers of Alcohol Use: Potential Diagnostic and Treatment Management Tools in Dual Diagnosis Care

Alcohol use disorders are highly prevalent conditions that generate a large fraction of the total public health burden. These disorders are concentrated in mentally ill populations, in which reliability of self-reporting of alcohol consumption may be especially compromised. The application of objective biomarkers for alcohol use may therefore play an important role in these patients. This article provides a description and comparative overview of traditional versus novel biomarkers of alcohol consumption. Greater professional familiarity with and use of novel biomarkers as diagnostic and treatment management tools may enhance clinical standards and research on alcohol use in patients with a dual diagnosis.

Advantages of achiral h.p.l.c. as a preparative step for chiral analysis in biological samples and its use in toxicokinetic studies

1. Achiral reverse-phase h.p.l.c. with semi-automated post-column fraction collection and solid-phase sample reconcentration, has been applied as the purification procedure during the enantiomeric quantification of two widely differing experimental drugs; an HMG-CoA reductase inhibitor (I) and an alpha 2-adrenoceptor antagonist (II). 2. The robust and specific achiral methodologies were available prior to the need for chiral analyses and recovery of drug from the fractions provided clean samples from a variety of biological matrices, without the need to develop compatible achiral/chiral mobile phases. 3. Compared with direct chiral chromatography of plasma extracts, this approach decreased the potential for metabolites and endogenous components to interfere or impair the performance of the chiral stationary phase. 4. The availability of quantitative data from achiral analysis of samples negated the need for internal standardization of the chiral analyses, helped confirm assay specificity and provided potential to determine enantiomeric ratios where only one isomer could be accurately measured. 5. Routine enantiomeric analyses were successfully carried out on samples taken from animals dosed orally with the racemic drugs, providing important data on the possible levels of exposure to individual enantiomers during toxicity testing.

Development of the Diet Habits Questionnaire for Use in Cardiac Rehabilitation

The objective of this study is to design a tool that could be used in the cardiac rehabilitation setting to quickly assess dietary habits and identify individual participants? dietary education requirements. An initial study compared a research diet history of 4 0 participants against the results of the Diet Habits Questionnaire. Concurrent validity has been established as there was a significant difference between mean (95% CI) intake of 5 .7 (0.6 - 10.7) g saturated fat 6.8 (2.9 - 10.8) g fibre and 417 (5 - 838) mg sodium between participants requiring additional dietary advice and those who do not require additional intervention based on the DHQ score. The inter-rater reliability of the DHQ was high with strength of agreement rated as moderate for fat and substantial for fibre and sodium. The Diet Habits Questionnaire was found to be a valid and reliable screening tool for the assessment of dietary habits in cardiac rehabilitation programs. Further research may establish its usefulness not just in cardiac rehabilitation, but in other health centres such as general practice and community health settings.