ABSTRACT
The ongoing pandemic of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a major threat to global health1 and the medical countermeasures available so far are limited2,3. Moreover, we currently lack a thorough understanding of the mechanisms of humoral immunity to SARS-CoV-24. Here we analyse a large panel of human monoclonal antibodies that target the spike (S) glycoprotein5, and identify several that exhibit potent neutralizing activity and fully block the receptor-binding domain of the S protein (SRBD) from interacting with human angiotensin-converting enzyme 2 (ACE2). Using competition-binding, structural and functional studies, we show that the monoclonal antibodies can be clustered into classes that recognize distinct epitopes on the SRBD, as well as distinct conformational states of the S trimer. Two potently neutralizing monoclonal antibodies, COV2-2196 and COV2-2130, which recognize non-overlapping sites, bound simultaneously to the S protein and neutralized wild-type SARS-CoV-2 virus in a synergistic manner. In two mouse models of SARS-CoV-2 infection, passive transfer of COV2-2196, COV2-2130 or a combination of both of these antibodies protected mice from weight loss and reduced the viral burden and levels of inflammation in the lungs. In addition, passive transfer of either of two of the most potent ACE2-blocking monoclonal antibodies (COV2-2196 or COV2-2381) as monotherapy protected rhesus macaques from SARS-CoV-2 infection. These results identify protective epitopes on the SRBD and provide a structure-based framework for rational vaccine design and the selection of robust immunotherapeutic agents.
Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/immunology , Pneumonia, Viral/prevention & control , Angiotensin-Converting Enzyme 2 , Animals , Antibodies, Monoclonal/immunology , Betacoronavirus/chemistry , Binding, Competitive , COVID-19 , Cell Line , Cross Reactions , Disease Models, Animal , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/immunology , Female , Humans , Macaca mulatta , Male , Mice , Middle Aged , Neutralization Tests , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolism , Pre-Exposure Prophylaxis , Severe acute respiratory syndrome-related coronavirus/chemistry , Severe acute respiratory syndrome-related coronavirus/immunology , SARS-CoV-2 , Severe Acute Respiratory Syndrome/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolismABSTRACT
ABSTRACTSmiles provide information about a social partner's affect and intentions during social interaction. Although always encountered within a specific situation, the influence of contextual information on smile evaluation has not been widely investigated. Moreover, little is known about the reciprocal effect of smiles on evaluations of their accompanying situations. In this research, we assessed how different smile types and situational contexts affected participants' social evaluations. In Study 1, 85 participants rated reward, affiliation, and dominance smiles embedded within either enjoyable, polite, or negative (unpleasant) situations. Context had a strong effect on smile ratings, such that smiles in enjoyable situations were rated as more genuine and joyful, as well as indicating less superiority than those in negative situations. In Study 2, 200 participants evaluated the situations that these smiles were perceived within (rather than the smiles themselves). Although situations paired with reward (vs. affiliation) smiles tended to be rated more positively, this effect was absent for negative situations. Ultimately, the findings point toward a reciprocal relationship between smiles and contexts, whereby the face influences evaluations of the situation and vice versa.
Subject(s)
Facial Expression , Smiling , Humans , Happiness , Reward , Social InteractionABSTRACT
SUMMARY: B-cell receptor (BCR) and T-cell receptor (TCR) repertoires are generated through somatic DNA rearrangements and are responsible for the molecular basis of antigen recognition in the immune system. Next-generation sequencing (NGS) of DNA and the falling cost of sequencing due to continued development of these technologies have made sequencing assays an affordable way to characterize the repertoire of adaptive immune receptors (sometimes termed the 'immunome'). Many new workflows have been developed to take advantage of NGS and have placed the resulting immunome datasets in the public domain. The scale of these NGS datasets has made it challenging to search through the Complementarity-determining region 3 (CDR3), which is responsible for imparting specific antibody-antigen interactions. Thus, there is an increasing demand for sequence analysis tools capable of searching through CDR3s from immunome data collections containing millions of sequences. To address this need, we created a software package called ClonoMatch that facilitates rapid searches in bulk immunome data for BCR or TCR sequences based on their CDR3 sequence or V3J clonotype. AVAILABILITY AND IMPLEMENTATION: Documentation, software support and the codebase are all available at https://github.com/crowelab/clonomatch. This software is distributed under the GPL v3 license.
ABSTRACT
BACKGROUND: Recent advances in DNA sequencing technologies have enabled significant leaps in capacity to generate large volumes of DNA sequence data, which has spurred a rapid growth in the use of bioinformatics as a means of interrogating antibody variable gene repertoires. Common tools used for annotation of antibody sequences are often limited in functionality, modularity and usability. RESULTS: We have developed PyIR, a Python wrapper and library for IgBLAST, which offers a minimal setup CLI and API, FASTQ support, file chunking for large sequence files, JSON and Python dictionary output, and built-in sequence filtering. CONCLUSIONS: PyIR offers improved processing speed over multithreaded IgBLAST (version 1.14) when spawning more than 16 processes on a single computer system. Its customizable filtering and data encapsulation allow it to be adapted to a wide range of computing environments. The API allows for IgBLAST to be used in customized bioinformatics workflows.
Subject(s)
Immunoglobulins/genetics , Receptors, Antigen, T-Cell/genetics , Sequence Alignment , Software , Base Sequence , Humans , Sequence Analysis, DNA , Time Factors , User-Computer InterfaceABSTRACT
Understanding the human antibody response to emerging viral pathogens is key to epidemic preparedness. As the size of the B cell response to a pathogenic-virus-protective antigen is poorly defined, we perform deep paired heavy- and light-chain sequencing in Ebola virus glycoprotein (EBOV-GP)-specific memory B cells, allowing analysis of the ebolavirus-specific antibody repertoire both genetically and functionally. This approach facilitates investigation of the molecular and genetic basis for the evolution of cross-reactive antibodies by elucidating germline-encoded properties of antibodies to EBOV and identification of the overlap between antibodies in the memory B cell and serum repertoire. We identify 73 public clonotypes of EBOV, 20% of which encode antibodies with neutralization activity and capacity to protect mice in vivo. This comprehensive analysis of the public and private antibody repertoire provides insight into the molecular basis of the humoral immune response to EBOV GP, which informs the design of vaccines and improved therapeutics.
Subject(s)
Ebolavirus , Hemorrhagic Fever, Ebola , Humans , Animals , Mice , Antibodies, Neutralizing , Antibodies, Viral , Antibody Formation , Prevalence , Glycoproteins/geneticsABSTRACT
Unrelated individuals can produce genetically similar clones of antibodies, known as public clonotypes, which have been seen in responses to different infectious diseases, as well as healthy individuals. Here we identify 37 public clonotypes in memory B cells from convalescent survivors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or in plasmablasts from an individual after vaccination with mRNA-encoded spike protein. We identify 29 public clonotypes, including clones recognizing the receptor-binding domain (RBD) in the spike protein S1 subunit (including a neutralizing, angiotensin-converting enzyme 2 [ACE2]-blocking clone that protects in vivo) and others recognizing non-RBD epitopes that bind the S2 domain. Germline-revertant forms of some public clonotypes bind efficiently to spike protein, suggesting these common germline-encoded antibodies are preconfigured for avid recognition. Identification of large numbers of public clonotypes provides insight into the molecular basis of efficacy of SARS-CoV-2 vaccines and sheds light on the immune pressures driving the selection of common viral escape mutants.
ABSTRACT
Unrelated individuals can produce genetically similar clones of antibodies, known as public clonotypes, which have been seen in responses to different infectious diseases as well as healthy individuals. Here we identify 37 public clonotypes in memory B cells from convalescent survivors of SARS-CoV-2 infection or in plasmablasts from an individual after vaccination with mRNA-encoded spike protein. We identified 29 public clonotypes, including clones recognizing the receptor-binding domain (RBD) in the spike protein S1 subunit (including a neutralizing, ACE2-blocking clone that protects in vivo ), and others recognizing non-RBD epitopes that bound the heptad repeat 1 region of the S2 domain. Germline-revertant forms of some public clonotypes bound efficiently to spike protein, suggesting these common germline-encoded antibodies are preconfigured for avid recognition. Identification of large numbers of public clonotypes provides insight into the molecular basis of efficacy of SARS-CoV-2 vaccines and sheds light on the immune pressures driving the selection of common viral escape mutants.
ABSTRACT
Immunoglobulin light chain amyloidosis is the most common form of systemic amyloidosis. AL amyloidosis is caused by a misfolded light chain produced by a clonal population of plasma cells. Disease status currently is defined by measuring the absolute quantity of serum free light chain protein, but this measurement often fails to identify the subclinical presence of clonal cells that may merit additional therapy. Next generation sequencing has the sensitivity to measure the relative amount of dominating light chains within the repertoire of a patient, and this technique is in clinical use to identify clonal populations of plasma cells for multiple myeloma, a related disorder. In this proof-of-concept study, we used bone marrow aspirates of AL amyloidosis positive patients and used reverse transcription of the antibody transcriptome followed by next generation sequencing to identify antibody variable-diversity-joining gene sequences for patients with immunoglobulin light chain amyloidosis, and demonstrate that this technology can be used to identify the dominant clone. The data also reveal differing patterns of overall antibody repertoire disruption in different patients. This method merits further study in larger prospective studies to establish its utility in detecting residual disease for patients with immunoglobulin light chain amyloidosis.
Subject(s)
Genes, Immunoglobulin , Immunoglobulin Light-chain Amyloidosis/genetics , Immunoglobulin Variable Region/genetics , Bone Marrow Cells , High-Throughput Nucleotide Sequencing/methods , Humans , Reverse Transcription , Sequence Analysis, RNAABSTRACT
The collection of T cell receptors (TCRs) generated by somatic recombination is large but unknown. We generate large TCR repertoire datasets as a resource to facilitate detailed studies of the role of TCR clonotypes and repertoires in health and disease. We estimate the size of individual human recombined and expressed TCRs by sequence analysis and determine the extent of sharing between individual repertoires. Our experiments reveal that each blood sample contains between 5 million and 21 million TCR clonotypes. Three individuals share 8% of TCRß- or 11% of TCRα-chain clonotypes. Sorting by T cell phenotypes in four individuals shows that 5% of naive CD4+ and 3.5% of naive CD8+ subsets share their TCRß clonotypes, whereas memory CD4+ and CD8+ subsets share 2.3% and 0.4% of their clonotypes, respectively. We identify the sequences of these shared TCR clonotypes that are of interest for studies of human T cell biology.
Subject(s)
Clone Cells/metabolism , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Adult , Amino Acid Sequence , DNA/genetics , Female , Genome, Human , Humans , Lymphocyte Subsets/immunology , Male , Middle Aged , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, Antigen, T-Cell, alpha-beta/chemistry , Young AdultABSTRACT
The COVID-19 pandemic is a major threat to global health for which there are only limited medical countermeasures, and we lack a thorough understanding of mechanisms of humoral immunity 1,2 . From a panel of monoclonal antibodies (mAbs) targeting the spike (S) glycoprotein isolated from the B cells of infected subjects, we identified several mAbs that exhibited potent neutralizing activity with IC 50 values as low as 0.9 or 15 ng/mL in pseudovirus or wild-type ( wt ) SARS-CoV-2 neutralization tests, respectively. The most potent mAbs fully block the receptor-binding domain of S (S RBD ) from interacting with human ACE2. Competition-binding, structural, and functional studies allowed clustering of the mAbs into defined classes recognizing distinct epitopes within major antigenic sites on the S RBD . Electron microscopy studies revealed that these mAbs recognize distinct conformational states of trimeric S protein. Potent neutralizing mAbs recognizing unique sites, COV2-2196 and COV2-2130, bound simultaneously to S and synergistically neutralized authentic SARS-CoV-2 virus. In two murine models of SARS-CoV-2 infection, passive transfer of either COV2-2916 or COV2-2130 alone or a combination of both mAbs protected mice from severe weight loss and reduced viral burden and inflammation in the lung. These results identify protective epitopes on the S RBD and provide a structure-based framework for rational vaccine design and the selection of robust immunotherapeutic cocktails.
ABSTRACT
Antibodies are a principal determinant of immunity for most RNA viruses and have promise to reduce infection or disease during major epidemics. The novel coronavirus SARS-CoV-2 has caused a global pandemic with millions of infections and hundreds of thousands of deaths to date 1,2 . In response, we used a rapid antibody discovery platform to isolate hundreds of human monoclonal antibodies (mAbs) against the SARS-CoV-2 spike (S) protein. We stratify these mAbs into five major classes based on their reactivity to subdomains of S protein as well as their cross-reactivity to SARS-CoV. Many of these mAbs inhibit infection of authentic SARS-CoV-2 virus, with most neutralizing mAbs recognizing the receptor-binding domain (RBD) of S. This work defines sites of vulnerability on SARS-CoV-2 S and demonstrates the speed and robustness of new antibody discovery methodologies.
ABSTRACT
Importance: Although stereotactic radiosurgery (SRS) is preferred for limited brain metastases from most histologies, whole-brain radiotherapy (WBRT) has remained the standard of care for patients with small cell lung cancer. Data on SRS are limited. Objective: To characterize and compare first-line SRS outcomes (without prior WBRT or prophylactic cranial irradiation) with those of first-line WBRT. Design, Setting, and Participants: FIRE-SCLC (First-line Radiosurgery for Small-Cell Lung Cancer) was a multicenter cohort study that analyzed SRS outcomes from 28 centers and a single-arm trial and compared these data with outcomes from a first-line WBRT cohort. Data were collected from October 26, 2017, to August 15, 2019, and analyzed from August 16, 2019, to November 6, 2019. Interventions: SRS and WBRT for small cell lung cancer brain metastases. Main Outcomes and Measures: Overall survival, time to central nervous system progression (TTCP), and central nervous system (CNS) progression-free survival (PFS) after SRS were evaluated and compared with WBRT outcomes, with adjustment for performance status, number of brain metastases, synchronicity, age, sex, and treatment year in multivariable and propensity score-matched analyses. Results: In total, 710 patients (median [interquartile range] age, 68.5 [62-74] years; 531 men [74.8%]) who received SRS between 1994 and 2018 were analyzed. The median overall survival was 8.5 months, the median TTCP was 8.1 months, and the median CNS PFS was 5.0 months. When stratified by the number of brain metastases treated, the median overall survival was 11.0 months (95% CI, 8.9-13.4) for 1 lesion, 8.7 months (95% CI, 7.7-10.4) for 2 to 4 lesions, 8.0 months (95% CI, 6.4-9.6) for 5 to 10 lesions, and 5.5 months (95% CI, 4.3-7.6) for 11 or more lesions. Competing risk estimates were 7.0% (95% CI, 4.9%-9.2%) for local failures at 12 months and 41.6% (95% CI, 37.6%-45.7%) for distant CNS failures at 12 months. Leptomeningeal progression (46 of 425 patients [10.8%] with available data) and neurological mortality (80 of 647 patients [12.4%] with available data) were uncommon. On propensity score-matched analyses comparing SRS with WBRT, WBRT was associated with improved TTCP (hazard ratio, 0.38; 95% CI, 0.26-0.55; P < .001), without an improvement in overall survival (median, 6.5 months [95% CI, 5.5-8.0] for SRS vs 5.2 months [95% CI, 4.4-6.7] for WBRT; P = .003) or CNS PFS (median, 4.0 months for SRS vs 3.8 months for WBRT; P = .79). Multivariable analyses comparing SRS and WBRT, including subset analyses controlling for extracranial metastases and extracranial disease control status, demonstrated similar results. Conclusions and Relevance: Results of this study suggest that the primary trade-offs associated with SRS without WBRT, including a shorter TTCP without a decrease in overall survival, are similar to those observed in settings in which SRS is already established.
Subject(s)
Brain Neoplasms/radiotherapy , Cranial Irradiation , Lung Neoplasms/radiotherapy , Radiosurgery , Small Cell Lung Carcinoma/radiotherapy , Aged , Brain Neoplasms/secondary , Female , Humans , Lung Neoplasms/pathology , Male , Middle Aged , Retrospective Studies , Small Cell Lung Carcinoma/pathologyABSTRACT
Antibodies are a principal determinant of immunity for most RNA viruses and have promise to reduce infection or disease during major epidemics. The novel coronavirus SARS-CoV-2 has caused a global pandemic with millions of infections and hundreds of thousands of deaths to date1,2. In response, we used a rapid antibody discovery platform to isolate hundreds of human monoclonal antibodies (mAbs) against the SARS-CoV-2 spike (S) protein. We stratify these mAbs into five major classes on the basis of their reactivity to subdomains of S protein as well as their cross-reactivity to SARS-CoV. Many of these mAbs inhibit infection of authentic SARS-CoV-2 virus, with most neutralizing mAbs recognizing the receptor-binding domain (RBD) of S. This work defines sites of vulnerability on SARS-CoV-2 S and demonstrates the speed and robustness of advanced antibody discovery platforms.
Subject(s)
Antibodies, Monoclonal/isolation & purification , Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Pneumonia, Viral/drug therapy , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/isolation & purification , Betacoronavirus/immunology , Betacoronavirus/pathogenicity , COVID-19 , Coronavirus Infections/immunology , Coronavirus Infections/virology , Humans , Pandemics , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Protein Binding , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/immunologyABSTRACT
Radiation therapy is an effective treatment for primary orbital lymphomas. Lens shielding with electrons can reduce the risk of high-grade cataracts in patients undergoing treatment for superficial tumors. This work evaluates the dosimetric effects of a suspended eye shield, placement of bolus, and varying electron energies. Film (GafChromic EBT3) dosimetry and relative output factors were measured for 6, 8, and 10 MeV electron energies. A customized 5-cm diameter circle electron orbital cutout was constructed for a 6 × 6-cm applicator with a suspended lens shield (8-mm diameter Cerrobend cylinder, 2.2-cm length). Point doses were measured using a scanning electron diode in a solid water phantom at depths representative of the anterior and posterior lens. Depth dose profiles were compared for 0-mm, 3-mm, and 5-mm bolus thicknesses. At 5 mm (the approximate distance of the anterior lens from the surface of the cornea), the percent depth dose under the suspended lens shield was reduced to 15%, 15%, and 14% for electron energies 6, 8, and 10 MeV, respectively. Applying bolus reduced the benefit of lens shielding by increasing the estimated doses under the block to 27% for 3-mm and 44% for 5-mm bolus for a 6 MeV incident electron beam. This effect is minimized with 8 MeV electron beams where the corresponding values were 15.5% and 18% for 3-mm and 5-mm bolus. Introduction of a 7-mm hole in 5-mm bolus to stabilize eye motion during treatment altered lens doses by about 1%. Careful selection of electron energy and consideration of bolus effects are needed to account for electron scatter under a lens shield.
Subject(s)
Electrons/therapeutic use , Eye Neoplasms/radiotherapy , Lymphoma, B-Cell, Marginal Zone/radiotherapy , Organ Sparing Treatments/methods , Humans , RadiometryABSTRACT
Similarity is central in human cognition, playing a role in a wide range of cognitive processes. In three studies, we demonstrate that subjective similarity may change as a function of temporal distance, with some events seeming more similar when considered in the near future, while others increase in similarity as temporal distance increases. Given the ubiquity of inter-temporal thought, and the fundamental role of similarity, these results have important implications for cognition in general.
Subject(s)
Cognition , Time Perception , Humans , Psychological TheoryABSTRACT
Maximal safe resection has long been the cornerstone of treatment for WHO grade I benign meningioma. However, as technology for both imaging and radiation delivery has advanced, radiation therapy has played an increasingly important role in the management of patients with WHO grade I meningioma. Radiation therapy, whether delivered as standard fractionated treatment over several weeks, stereotactic radiosurgery over 1 session, or multisession stereotactic radiation therapy, has been shown to provide excellent local control when used as an adjunct to surgery or as primary treatment. Here, we review the indications for radiation therapy for patients with WHO grade I meningioma, as well as the various techniques that have been developed. We also review the toxicities and late effects associated with treatment.
Subject(s)
Meningeal Neoplasms/radiotherapy , Meningioma/radiotherapy , Adult , Brain Neoplasms , Dose Fractionation, Radiation , Humans , Meningeal Neoplasms/pathology , Meningioma/pathology , Neoplasm Grading , Radiosurgery/methodsABSTRACT
Prior research has established that while the use of concrete, familiar examples can provide many important benefits for learning, it is also associated with some serious disadvantages, particularly in learners' ability to recognize and transfer their knowledge to new analogous situations. However, it is not immediately clear whether this pattern would hold in real world educational contexts, in which the role of such examples in student engagement and ease of processing might be of enough importance to overshadow any potential negative impact. We conducted two experiments in which curriculum-relevant material was presented in natural classroom environments, first with college undergraduates and then with middle-school students. All students in each study received the same relevant content, but the degree of contextualization in these materials was varied between students. In both studies, we found that greater contextualization was associated with poorer transfer performance. We interpret these results as reflecting a greater degree of embeddedness for the knowledge acquired from richer, more concrete materials, such that the underlying principles are represented in a less abstract and generalizable form.
ABSTRACT
High-grade gliomas are rapidly progressing and generally fatal neoplasms of the brain. Chemotherapy has continued to provide only limited benefit for patients harboring these tumors. The recurrence of common mutations, combined with the similarities of many of the acquired capabilities and characteristics of solid tumors, suggest many common therapeutic targets. During the past few decades, an increased understanding of many of the cellular regulatory mechanisms associated with carcinogenesis has provided an opportunity for the development of pathway-specific small molecule targeted inhibitors (SMIs). This article reviews the use of SMIs in the treatment of high-grade glioma.
Subject(s)
Antineoplastic Agents/therapeutic use , Brain Neoplasms/drug therapy , ErbB Receptors/antagonists & inhibitors , Glioblastoma/drug therapy , Receptors, Platelet-Derived Growth Factor/antagonists & inhibitors , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Clinical Trials as Topic , Humans , Phosphoinositide-3 Kinase Inhibitors , Signal Transduction , ras Proteins/antagonists & inhibitorsABSTRACT
Previous research has consistently found that spontaneous analogical transfer is strongly tied to concrete and contextual similarities between the cases. However, that work has largely failed to acknowledge that the relevant factor in transfer is the similarity between individuals' mental representations of the situations rather than the overt similarities between the cases themselves. Across several studies, we found that participants were able to transfer strategies learned from a perceptually concrete simulation of a physical system to a task with very dissimilar content and appearance. This transfer was reflected in better performance on the transfer task when its underlying dynamics were consistent rather than inconsistent with the preceding training task. Our data indicate that transfer in these tasks relies on the perceptual and spatial nature of the training task but does not depend on direct interaction with the system, with participants performing equally well after simply observing the concrete simulation. We argue that participants generated a spatial, dynamic, and force-based mental model while interacting with the training simulation and tended to spontaneously interpret the transfer task according to this primed model. Unexpectedly, our data consistently show that transfer was independent of reported recognition of the analogy between tasks: Although such recognition was associated with better overall performance, it was not associated with better transfer (in terms of applying an appropriate strategy). Together, these findings suggest that analogical transfer between overtly dissimilar cases may be much more common--and much more relevant to our cognitive processing--than is generally assumed.
Subject(s)
Computer Simulation , Kinesthesis , Models, Psychological , Motion Perception/physiology , Transfer, Psychology , Analysis of Variance , Functional Laterality , Humans , Problem Solving/physiology , Recognition, Psychology , Students , UniversitiesABSTRACT
Detection of early tumor responses to treatment can give an indication of clinical outcome. Positron emission tomography measurements of the uptake of the glucose analog, [(18)F] 2-fluoro-2-deoxy-D-glucose (FDG), have demonstrated their potential for detecting early treatment response in the clinic. We have shown recently that (13)C magnetic resonance spectroscopy and spectroscopic imaging measurements of the uptake and conversion of hyperpolarized [1-(13)C]pyruvate into [1-(13)C]lactate can be used to detect treatment response in a murine lymphoma model. The present study compares these magnetic resonance measurements with changes in FDG uptake after chemotherapy. A decrease in FDG uptake was found to precede the decrease in flux of hyperpolarized (13)C label between pyruvate and lactate, both in tumor cells in vitro and in tumors in vivo. However, the magnitude of the decrease in FDG uptake and the decrease in pyruvate to lactate flux was comparable at 24 hours after drug treatment. In cells, the decrease in FDG uptake was shown to correlate with changes in plasma membrane expression of the facilitative glucose transporters, whereas the decrease in pyruvate to lactate flux could be explained by an increase in poly(ADP-ribose) polymerase activity and subsequent depletion of the NAD(H) pool. These results show that measurement of flux between pyruvate and lactate may be an alternative to FDG-positron emission tomography for imaging tumor treatment response in the clinic.