Evaluation of eight lateral flow tests for the detection of anti-SARS-CoV-2 antibodies in a vaccinated population.

BACKGROUND: Rapid determination of an individual's antibody status can be beneficial in understanding an individual's immune response to SARS-CoV-2 and for initiation of therapies that are only deemed effective in sero-negative individuals. Antibody lateral flow tests (LFTs) have potential to address this need as a rapid, point of care test. METHODS: Here we present a proof-of-concept evaluation of eight LFT brands using sera from 95 vaccinated individuals to determine sensitivity for detecting vaccination generated antibodies. Samples were analysed on eight different brands of antibody LFT and an automated chemiluminescent microparticle immunoassay (CMIA) that identifies anti-spike antibodies which was used as our reference standard. RESULTS: All 95 (100%) participants tested positive for anti-spike antibodies by the chemiluminescent microparticle immunoassay (CMIA) reference standard post-dose two of their SARS-CoV-2 vaccine: BNT162b2 (Pfizer/BioNTech, n = 60), AZD1222 (AstraZeneca, n = 31), mRNA-1273 (Moderna, n = 2) and Undeclared Vaccine Brand (n = 2). Sensitivity increased from dose one to dose two in six out of eight LFTs with three tests achieving 100% sensitivity at dose two in detecting anti-spike antibodies. CONCLUSIONS: These tests are demonstrated to be highly sensitive to detect raised antibody levels in vaccinated individuals. RDTs are low cost and rapid alternatives to ELISA based systems.

Practical Characterization Strategies for Comparison, Qualification, and Selection of Cell Viability Detection Methods for Cellular Therapeutic Product Development and Manufacturing.

Cellular therapy development and manufacturing has focused on providing novel therapeutic cell-based products for various diseases. The International Organization for Standardization (ISO) has provided guidance on critical quality attributes (CQAs) that shall be considered when testing and releasing cellular therapeutic products. Cell count and viability measurements are two of the CQAs that are determined during development, manufacturing, testing, and product release. The ISO Cell Counting Standard Part 1 and 2 addressed the needs for improving the quality of cell counting results. However, there is currently no guidance on the qualification and selection of a fit-for-purpose cell viability detection method. In this work, we present strategies for the characterization and comparison of AO/PI and AO/DAPI staining methods using the heat-killed (HK) and low temperature/nutrient-deprived (LT/ND) cell death models to evaluate the comparability of cell viability measurements and identify potential causes of differences. We compared the AO/PI and AO/DAPI staining methods using HK and LT/ND-generated dead cells, investigated the staining time effects on cell viability measurements, and determined their viability linearity with different mixtures of live and dead cells. Furthermore, we validated AO/PI and AO/DAPI cell viability measurement with a long-term cell proliferation assay. Finally, we demonstrate a practical example of cell viability measurement comparison using AO/PI and AO/DAPI on antibiotic-selected transduced Jurkat and THP-1 cells to select a fit-for-purpose method for functional genomics screening. The proposed strategies may potentially enable scientists to properly characterize, compare, and select cell viability detection methods that are critical for cellular therapeutic product development and manufacturing.

The effects of episode spacing on adult's reports of a repeated event.

Witnesses' reports of repeated events have been the focus of much research; however, the spacing interval between each episode of the event has differed greatly. The aim of the current study was to determine whether spacing interval affects participants' memory reports. Adults (N = 217) watched one (n = 52) or four videos depicting workplace bullying. The repeated event participants watched the four videos all in one day (n = 55), one per day over four consecutive days (n = 60), or one every three days over 12 days (n = 50). One week after the last (or only) video, participants reported on that video and answered some reflective questions about the procedure. Repeated-event participants also reported on what usually happens across the videos. Single-event participants reported proportionally more accurate information about the target video than repeated-event participants, and spacing interval did not affect repeated event participants' accuracy. However, accuracy scores were close to ceiling while errors rates were at floor levels, preventing us from drawing strong conclusions. We found some evidence that episode spacing affected participants' perceptions of their memory performance. Overall, spacing may have a minimal effect on adults' memory for repeated events, but further research is required.

"[This] system was not made for [you]:" A case for decolonial Scientia.

BACKGROUND: Sylvia Wynter's "recoded" form of science called decolonial Scientia (DS) is grounded in an understanding of humans as simultaneously biological and cultural. DS includes narrative interventions that destabilize Western scientific authority, and address limitations that empirical data collection and analysis place on capturing simultaneous realities. Therefore, Wynter's narrative "languaging" is both scientific critique and grounded in a tradition of Black radical imagining. AIMS: In this article, I use languaging to destabilize the canonical narrative tied to W. M. Cobb's production of the article "Race and Runners." The standard telling focuses on Cobb's examination of Owens' lower extremities to expose the fallacy of racial differences in athletic ability. Destabilization of the narrative allows for identifying relational complexities between actors involved in the canonical story - and identifying ideologies embedded within it that guide our deconstructions of biological race. My alter(ed)native subjectivity informs my use of languaging to argue that the relationship between narrative and research practices belie Western scientific/unscientific binaries. MATERIALS AND METHODS: Audiovisual and documentary sources of the public-facing "Race and Runners" story were subject to comparative analysis to verify the content and order of events in the canonical narrative. Letters focused on race and athletic ability obtained from the W. Montague Cobb Manuscript Collection at Howard University serve as "apocryphal" sources of information. Correspondence between Cobb and a representative member of the public named Howard Duncan took place within a period immediately before, during and after Cobb publishes "Race and Runners" in the Journal of Health and Physical Education. Contents were subject to a systematic analysis that involved reviewing documents to identify statements reflecting scientific practices, human interactions and relationships between race and athletic ability reflected in the canonical narrative. Contents were also examined for statements relevant to the narrative that departed from or added to the canonical story in the same three areas. Details regarding departures and additions were recorded along with the specific part of the narrative to which they corresponded. Narrative departures and additions were articulated with the canonical narrative in the interest of destabilizing it to identify "knots of ideas, histories and narratives that, contrary to Western science, can only be legible in relation to one another" (McKittrick, 2015b p. 2). RESULTS: Letters exchanged between Cobb and Duncan reveal dynamics that are obscured in the canonical storyline. For instance, Duncan's ability as a white male to assert himself as Cobb's peer demonstrates how racialized power is enacted through science. This is also reflected in Owens' position in the narrative as a voiceless object of knowledge. Letters also present Cobb's identity beyond being a "pioneer," rendering how he is studying and experiencing racism. This includes how he refuses to engage Duncan as a peer. DISCUSSION: More than mere stories, narratives are motivating and instructive forces that shape how we study human biology and use our research to oppose biological notions of race. Correspondence between Cobb and Duncan reveals how Western scientific ideologies that reinforce prescribed roles and boundaries are embedded in narratives. These ideologies can limit the transformative potential of our approaches to contesting biological notions of race.

Utility of venous blood gases for the assessment of traumatic shock: a prospective observational study.

BACKGROUND: ABG samples are often obtained in trauma patients to assess shock severity. Venous blood gas (VBG) sampling, which is less invasive, has been widely used to assess other forms of shock. The study aim was to determine the agreement between VBG and ABG measurements in trauma. METHODS: Patients were enrolled at an Australian trauma centre between October 2016 and October 2018. Bland-Altman limits of agreement (LOA) between paired blood gas samples taken <30 min apart were used to quantify the extent of agreement. The impact of using only VBG measurements was considered using an a priori plan. Cases where venous sampling failed to detect 'concerning levels' were flagged using evidence-based cut-offs: pH ≤7.2, base deficit (BD) ≤-6, bicarbonate <21 and lactate ≥4. Case summaries of these patients were assessed by independent trauma clinicians as to whether an ABG would change expected management. RESULTS: During the study period 176 major trauma patients had valid paired blood gas samples available for analysis. The median time difference between paired measurements was 11 min (IQR 6-17). There was a predominance of men (81.8%) and blunt trauma (92.0%). Median Injury Severity Score was 13 (range 1-75) and inpatient mortality was 6.3%. Mean difference (ABG-VBG) and LOA between paired arterial and venous measurements were 0.036 (LOA -0.048 to 0.120) for pH, -1.27 mmol/L (LOA -4.35 to 1.81) for BD, -0.64 mmol/L (LOA -1.86 to 0.57) for lactate and -1.97 mmol/L (LOA -5.49 to 1.55) for bicarbonate. Independent assessment of the VBG 'false negative' cases (n=20) suggested an ABG would change circulatory management in two cases. CONCLUSIONS: In trauma patients VBG and ABG parameters displayed suboptimal agreement. However, in cases flagged as VBG 'false negative' independent review indicated that the availability of an ABG was unlikely to change management.

Development of chlorine-induced lung injury in the anesthetized, spontaneously breathing pig.

Chlorine is a toxic industrial chemical produced in vast quantities globally, being used in a range of applications such as water purification, sanitation and industrial processes. Its use and transport cannot be restricted; exposure may occur following accidental or deliberate releases. The OPCW recently verified the use of chlorine gas against civilians in both Syria and Iraq. Chlorine inhalation produces damage to the lungs, which may result in the development of an acute lung injury, respiratory failure and death. Treatment remains an intractable problem. Our objective was to develop a clinically relevant pre-clinical model of a moderate to severe lung injury in the pig. This would enable future assessment of therapeutic drugs or interventions to be implemented in the pre-hospital phase after exposure. Due to the irritant nature of chlorine, a number of strategies for exposing terminally anesthetized pigs needed to be investigated. A number of challenges (inconsistent acute changes in respiratory parameters; early deaths), resulted in a moderate to severe lung injury not being achieved. However, most pigs developed a mild lung injury by 12 h. Further investigation is required to optimize the model and enable the assessment of therapeutic candidates. In this paper we describe the exposure strategies used and discuss the challenges encountered in establishing a model of chlorine-induced lung injury. A key aim is to assist researchers navigating the challenges of producing a clinically relevant model of higher dose chlorine exposure where animal welfare is protected by use of terminal anesthesia.

Direct and Absolute Quantification of over 1800 Yeast Proteins via Selected Reaction Monitoring.

Defining intracellular protein concentration is critical in molecular systems biology. Although strategies for determining relative protein changes are available, defining robust absolute values in copies per cell has proven significantly more challenging. Here we present a reference data set quantifying over 1800Saccharomyces cerevisiaeproteins by direct means using protein-specific stable-isotope labeled internal standards and selected reaction monitoring (SRM) mass spectrometry, far exceeding any previous study. This was achieved by careful design of over 100 QconCAT recombinant proteins as standards, defining 1167 proteins in terms of copies per cell and upper limits on a further 668, with robust CVs routinely less than 20%. The selected reaction monitoring-derived proteome is compared with existing quantitative data sets, highlighting the disparities between methodologies. Coupled with a quantification of the transcriptome by RNA-seq taken from the same cells, these data support revised estimates of several fundamental molecular parameters: a total protein count of ∼100 million molecules-per-cell, a median of ∼1000 proteins-per-transcript, and a linear model of protein translation explaining 70% of the variance in translation rate. This work contributes a "gold-standard" reference yeast proteome (including 532 values based on high quality, dual peptide quantification) that can be widely used in systems models and for other comparative studies.

The proto-oncogene PBF binds p53 and is associated with prognostic features in colorectal cancer.

The PTTG1-binding factor (PBF) is a transforming gene capable of eliciting tumor formation in xenograft models. However, the precise role of PBF in tumorigenesis and its prognostic value as a cancer biomarker remain largely uncharacterised, particularly in malignancies outside the thyroid. Here, we provide the first evidence that PBF represents a promising prognostic marker in colorectal cancer. Examination of a total of 39 patients demonstrated higher PBF expression at both the mRNA (P = 0.009) and protein (P < 0.0001) level in colorectal tumors compared to matched normal tissue. Critically, PBF was most abundant in colorectal tumors associated with Extramural Vascular Invasion (EMVI), increased genetic instability (GI) and somatic TP53 mutations, all features linked with recurrence and poorer patient survival. We further demonstrate by glutathione-S-transferase (GST) pull-down and coimmunoprecipitation that PBF binds to the tumor suppressor protein p53, as well as to p53 mutants (Δ126-132, M133K, V197E, G245D, I255F and R273C) identified in the colorectal tumors. Importantly, overexpression of PBF in colorectal HCT116 cells interfered with the transcriptional activity of p53-responsive genes such as mdm2, p21 and sfn. Diminished p53 stability (> 90%; P < 0.01) was also evident with a concurrent increase in ubiquitinated p53. Human colorectal tumors with wild-type TP53 and high PBF expression also had low p53 protein levels (P < 0.05), further emphasizing a putative interaction between these genes in vivo. Overall, these results demonstrate an emerging role for PBF in colorectal tumorigenesis through regulating p53 activity, with implications for PBF as a prognostic indicator for invasive tumors.

A novel interaction between FRMD7 and CASK: evidence for a causal role in idiopathic infantile nystagmus.

Idiopathic infantile nystagmus (IIN) is a genetically heterogeneous disorder of eye movement that can be caused by mutations in the FRMD7 gene that encodes a FERM domain protein. FRMD7 is expressed in the brain and knock-down studies suggest it plays a role in neurite extension through modulation of the actin cytoskeleton, yet little is known about its precise molecular function and the effects of IIN mutations. Here, we studied four IIN-associated missense mutants and found them to have diverse effects on FRMD7 expression and cytoplasmic localization. The C271Y mutant accumulates in the nucleus, possibly due to disruption of a nuclear export sequence located downstream of the FERM-adjacent domain. While overexpression of wild-type FRMD7 promotes neurite outgrowth, mutants reduce this effect to differing degrees and the nuclear localizing C271Y mutant acts in a dominant-negative manner to inhibit neurite formation. To gain insight into FRMD7 molecular function, we used an IP-MS approach and identified the multi-domain plasma membrane scaffolding protein, CASK, as a FRMD7 interactor. Importantly, CASK promotes FRMD7 co-localization at the plasma membrane, where it enhances CASK-induced neurite length, whereas IIN-associated FRMD7 mutations impair all of these features. Mutations in CASK cause X-linked mental retardation. Patients with C-terminal CASK mutations also present with nystagmus and, strikingly, we show that these mutations specifically disrupt interaction with FRMD7. Together, our data strongly support a model whereby CASK recruits FRMD7 to the plasma membrane to promote neurite outgrowth during development of the oculomotor neural network and that defects in this interaction result in nystagmus.

Repositioning the Cobb human archive: the merger of a skeletal collection and its texts.

The W. Montague Cobb skeletal collection, mainly comprised of African Americans living in Washington, DC, before 1969, is an important collection for human biological studies of the African Diaspora. This article outlines the process of constructing an improved study sample for biocultural analysis by merging skeletal remains from the collection with their associated texts. The merging allows for the inclusion of individuals from the original series for whom we no longer have skeletons. We argue that this step is necessary to construct a data set that reflects the demographic breadth (age, ethnicity, social class) of the original collection, taking into account a substantial number of skeletons lost during storage and disuse. The mechanics of this process were informed by a critical and humanistic orientation toward human biological study built upon the following premises: (1) scientific investigation is not an objective or passive practice, nor must it be; and, (2) relevant, publically accessible human biological research requires competence with social justice issues, as well as previous and current scholarship focused on addressing those issues. This approach to sample construction engages skeletal remains as biological and social products, and enhances the social and translational implications of our research practices.

Phospholipid chlorohydrins as chlorine exposure biomarkers in a large animal model.

Chlorine is a toxic industrial chemical that has been used as a chemical weapon in recent armed conflicts. Confirming human exposure to chlorine has proven challenging, and there is currently no established method for analyzing human biomedical samples to unambiguously verify chlorine exposure. In this study, two chlorine-specific biomarkers: palmitoyl-oleoyl phosphatidylglycerol chlorohydrin (POPG-HOCl) and the lipid derivative oleoyl ethanolamide chlorohydrin (OEA-HOCl) are shown in bronchoalveolar lavage fluid (BALF) samples from spontaneously breathing pigs after chlorine exposure. These biomarkers are formed by the chemical reaction of chlorine with unsaturated phospholipids found in the pulmonary surfactant, which is present at the gas-liquid interface within the lung alveoli. Our results strongly suggest that lipid chlorohydrins are promising candidate biomarkers in the development of a verification method for chlorine exposure. The establishment of verified methods capable of confirming the illicit use of toxic industrial chemicals is crucial for upholding the principles of the Chemical Weapons Convention (CWC) and enforcing the ban on chemical weapons. This study represents the first published dataset in BALF revealing chlorine biomarkers detected in a large animal. Furthermore, these biomarkers are distinct in that they originate from molecular chlorine rather than hypochlorous acid.

Ethical futures in biological anthropology: Research, teaching, community engagement, and curation involving deceased individuals.

Although ethical reforms in biological anthropology have gained ground in recent years, there is still a scarcity of ethical standards for work involving historical documented collections (HDCs) at US museums and universities. These collections of deceased individuals were created in the late 19th to mid-20th centuries under anatomy laws that targeted socially marginalized communities and allowed for the dissection of these individuals without their consent. Due to the extensive information associated with the individuals and made available to researchers, these collections have served as foundational resources for theory and methods development in biological anthropology into the 21st century. Recognizing the need for ethical guidelines for research, teaching and training, community engagement, and curation involving HDCs, we held a workshop called "Ethical Futures for Curation, Research, and Teaching in Biological Anthropology" on November 15-17, 2021. Here we summarize the conversations and major points of consensus among the workshop participants on these topics in order to advance these ethical considerations more broadly across the field.

Skin decontamination of Carfentanil in vitro.

Skin decontamination of Chemical Biological Radioactive and Nuclear (CBRN) materials involves the timely and effective removal of the contaminants from the skin surface. The current work evaluated Fuller's Earth & The Reactive Skin Decontaminant Lotion Kit (RSDL®) to investigate whether they were as efficacious against free base Carfentanil skin contamination as they are against chemical warfare agents. The in vitro methodology used allowed for evaluation of decontamination regimens as specified by the decontaminant manufacturer rather than as an application of a bolus dose left in situ for the study duration. A selection of novel decontaminants, including Dermal Decontamination Gel (DDGel), Trivorex®, itaconic acid (IA), N,N'-methylenebisacrylamide (MBA), 2-trifluoromethylacrylic acid (TFMAA) and NanoSan Sorb were also tested for efficacy. All the evaluated decontaminants were successful at removing the majority of the Carfentanil skin surface contamination. The current work has shown that the Fuller's Earth decontamination kit, removes as much (or more) free base carfentanil from the skin surface in comparison to other products tested in this study series.

William Montague Cobb: Near the African diasporic origins of activist and biocultural anthropology.

William Montague Cobb, AB, MD, PhD, was the first African American PhD in anatomy and physical anthropology. He produced 1,100 publications while a professor at Howard University. His influence on the civil rights struggle from the 1930s to 1970s was profound as were his contributions to science and medical history. This article shows how he continued the activist and interdisciplinary traditions of African diasporic intellectuals and that these innovated what is today labeled biocultural anthropology, which focuses on the political, economic, and other societal influences on human biology and health. The human biology of the White "mainstream" has tended toward reductionism, biodeterminism, and eugenics. It drew a causal arrow from biology to society. Had they been able to listen to Black intellectuals, the world might have avoided the tragedy of mid-20th century eugenics and its long continuing biodeterministic shadow.

Adaptation of a Modified Diet Quality Index to Quantify Healthfulness of Food-Related Toy Sets.

The objective of this cross-sectional study was to examine the construct validity of an adapted modified Diet Quality Index (aDQI) as a measure of the healthfulness of food-related toy sets for young children (3-8 years). A standardized online search was used to identify toy sets (n = 50) from 10 retailers. An aDQI score (aDQI score, range 0-50) was determined for each toy set, mean (standard deviation) = 28.7 (6.1). Regression analyses demonstrated a positive association between aDQI score and percentage of dairy, refined grains, protein, vegetables, and fruit and inverse association with percentage of desserts, sugar-sweetened beverages, and total number of servings. Sets contained more protein and fewer fruits than recommended. The aDQI score demonstrates construct validity to objectively assess the healthfulness of food-related toy sets. There is opportunity for toy manufacturers to make changes to improve the healthfulness in toy sets for young children, and future research can explore the impact of food-related toy sets on nutrition behaviors.

A prospective diagnostic evaluation of accuracy of self-taken and healthcare worker-taken swabs for rapid COVID-19 testing.

BACKGROUND: Rapid diagnostic tests (RDTs) developed for point of care detection of SARS-CoV-2 antigen are recommended by WHO to use trained health care workers to collect samples. We hypothesised that self-taken samples are non-inferior for use with RDTs to diagnose COVID-19. We designed a prospective diagnostic evaluation comparing self-taken and healthcare worker (HCW)-taken throat/nasal swabs to perform RDTs for SARS-CoV-2, and how these compare to RT-PCR. METHODS: Eligible participants 18 years or older with symptoms of COVID-19. 250 participants recruited at the NHS Test and Trace drive-through community PCR testing site (Liverpool, UK); one withdrew before analysis. Self-administered throat/nasal swab for the Covios® RDT, a trained HCW taken throat/nasal sample for PCR and HCW comparison throat/nasal swab for RDT were collected. RDT results were compared to RT-PCR, as the reference standard, to calculate sensitivity and specificity. FINDINGS: Seventy-five participants (75/249, 30.1%) were positive by RT-PCR. RDTs with self-taken swabs had a sensitivity of 90.5% (67/74, 95% CI: 83.9-97.2), compared to 78.4% (58/74, 95% CI: 69.0-87.8) for HCW-taken swabs (absolute difference 12.2%, 95% CI: 4.7-19.6, p = 0.003). Specificity for self-taken swabs was 99.4% (173/174, 95% CI: 98.3-100.0), versus 98.9% (172/174, 95% CI: 97.3-100.0) for HCW-taken swabs (absolute difference 0.6%, 95% CI: 0.5-1.7, p = 0.317). The PPV of self-taken RDTs (98.5%, 67/68, 95% CI: 95.7-100.0) and HCW-taken RDTs (96.7%, 58/60, 95% CI 92.1-100.0) were not significantly different (p = 0.262). However, the NPV of self-taken swab RDTs was significantly higher (96.1%, 173/180, 95% CI: 93.2-98.9) than HCW-taken RDTs (91.5%, 172/188, 95% CI 87.5-95.5, p = 0.003). INTERPRETATION: In conclusion, self-taken swabs for COVID-19 testing offer an accurate alternative to healthcare worker taken swabs for use with RDTs. Our results demonstrate that, with no training, self-taken throat/nasal samples can be used by lay individuals as part of rapid testing programmes for symptomatic adults. This is especially important where the lack of trained healthcare workers restricts access to testing.

Global absolute quantification of a proteome: Challenges in the deployment of a QconCAT strategy.

In this paper, we discuss the challenge of large-scale quantification of a proteome, referring to our programme that aims to define the absolute quantity, in copies per cell, of at least 4000 proteins in the yeast Saccharomyces cerevisiae. We have based our strategy on the well-established method of stable isotope dilution, generating isotopically labelled peptides using QconCAT technology, in which artificial genes, encoding concatenations of tryptic fragments as surrogate quantification standards, are designed, synthesised de novo and expressed in bacteria using stable isotopically enriched media. A known quantity of QconCAT is then co-digested with analyte proteins and the heavy:light isotopologues are analysed by mass spectrometry to yield absolute quantification. This workflow brings issues of optimal selection of quantotypic peptides, their assembly into QconCATs, expression, purification and deployment.

Protein disulphide isomerase family members show distinct substrate specificity: P5 is targeted to BiP client proteins.

At least 17 members of the protein disulphide isomerase (PDI) family of oxidoreductases are present in the endoplasmic reticulum (ER) of mammalian cells. They are thought to catalyse disulphide formation to aid folding or to regulate protein function; however, little is known about their individual functions. Here, we show that some proteins that enter the ER are clients for single oxidoreductases, whereas others are clients for several PDI-like enzymes. We previously identified potential substrates for ERp57, and here identify substrates for ERp18 and ERp46. In addition, we analysed the specificity of substrates towards PDI, ERp72, ERp57, ERp46, ERp18 and P5. Strikingly, ERp18 shows specificity towards a component of the complement cascade, pentraxin-related protein PTX3, whereas ERp46 has specificity towards peroxiredoxin-4, a thioredoxin peroxidase. By contrast, most PDI family members react with Ero1alpha. Moreover, P5 forms a non-covalent complex with immunoglobulin heavy chain binding protein (BiP) and shows specificity towards BiP client proteins. These findings highlight cooperation between BiP and P5, and demonstrate that individual PDI family members recognise specific substrate proteins.

A novel mechanism of sodium iodide symporter repression in differentiated thyroid cancer.

Differentiated thyroid cancers and their metastases frequently exhibit reduced iodide uptake, impacting on the efficacy of radioiodine ablation therapy. PTTG binding factor (PBF) is a proto-oncogene implicated in the pathogenesis of thyroid cancer. We recently reported that PBF inhibits iodide uptake, and have now elucidated a mechanism by which PBF directly modulates sodium iodide symporter (NIS) activity in vitro. In subcellular localisation studies, PBF overexpression resulted in the redistribution of NIS from the plasma membrane into intracellular vesicles, where it colocalised with the tetraspanin CD63. Cell-surface biotinylation assays confirmed a reduction in plasma membrane NIS expression following PBF transfection compared with vector-only treatment. Coimmunoprecipitation and GST-pull-down experiments demonstrated a direct interaction between NIS and PBF, the functional consequence of which was assessed using iodide-uptake studies in rat thyroid FRTL-5 cells. PBF repressed iodide uptake, whereas three deletion mutants, which did not localise within intracellular vesicles, lost the ability to inhibit NIS activity. In summary, we present an entirely novel mechanism by which the proto-oncogene PBF binds NIS and alters its subcellular localisation, thereby regulating its ability to uptake iodide. Given that PBF is overexpressed in thyroid cancer, these findings have profound implications for thyroid cancer ablation using radioiodine.