Technical Advance
Abstract
The challenge of discovering a completely new human tumor virus of unknown phylogeny or sequence depends on detecting viral molecules and differentiating them from host molecules in the virus-associated neoplasm. We developed differential peptide subtraction (DPS) using differential mass-spectrometry (dMS) followed by targeted analysis to facilitate this discovery. We validated this approach by analyzing Merkel cell carcinoma (MCC), an aggressive human neoplasm, in which ~80% of cases are caused by the human Merkel cell polyomavirus (MCV). Approximately 20% of MCC have a high mutational burden and are negative for MCV, but are microscopically indistinguishable from virus positive cases. Using 23 (12 MCV positive, 11 MCV negative) formalin-fixed MCC, DPS identified both viral and human biomarkers (MCV Large T antigen, CDKN2AIP, SERPINB5 and TRIM29) that discriminates MCV positive and negative MCC. Statistical analysis of 498,131 dMS features not matching the human proteome by DPS revealed 562 (0.11%) to be up-regulated in virus-infected samples. Remarkably, four (20%) of the top 20 candidate MS spectra originated from MCV T oncoprotein peptides and confirmed by reverse translation degenerate oligonucleotide sequencing. DPS is a robust proteomic approach to identify novel viral sequences in infectious tumors when nucleic acid-based methods are not feasible.
Authors
Tuna Toptan, Pamela S. Cantrell, Xuemei Zeng, Yang Liu, Mai Sun, Nathan A. Yates, Yuan Chang, Patrick S. Moore
Abstract
Infections caused by multi-drug resistant Staphylococcus aureus, especially MRSA, are responsible for high mortality and morbidity worldwide. Resistant lineages were previously confined to hospitals, but are now also causing infections among healthy individuals in the community. It is therefore imperative to explore therapeutic avenues that are less prone to raise drug resistance compared to today’s antibiotics. An opportunity to achieve this ambitious goal could be provided by targeted antimicrobial photodynamic therapy (aPDT), which relies on the combination of a bacteria-specific targeting agent and light-induced generation of reactive oxygen species by an appropriate photosensitizer. Here we conjugated the near-infrared photosensitizer IRDye700DX to a fully human monoclonal antibody, specific for the invariantly expressed staphylococcal antigen IsaA. The resulting immunoconjugate 1D9-700DX was characterized biochemically and in preclinical infection models. As demonstrated in vitro, in vivo, and in a human post-mortem orthopedic implant infection model, targeted aPDT with 1D9-700DX is highly effective. Importantly, combined with the non-toxic aPDT-enhancing agent potassium iodide, 1D9-700DX overcomes the antioxidant properties of human plasma and fully eradicates high titers of MRSA. We show that the developed immunoconjugate 1D9-700DX targets MRSA and kills it upon illumination with red light, without causing collateral damage to human cells.
Authors
Mafalda Bispo, Andrea Anaya-Sanchez, Sabrina Suhani, Elisa J.M. Raineri, Marina López-Álvarez, Marjolein Heuker, Wiktor Szymański, Francisco Romero Pastrana, Girbe Buist, Alexander R. Horswill, Kevin P. Francis, Gooitzen M. van Dam, Marleen van Oosten, Jan Maarten van Dijl
Abstract
Plasma antimalarial antibody can mediate anti-parasite immunity but has not previously been characterized at the molecular level. Here, we develop an innovative strategy to characterize humoral responses by integrating profiles of plasma immunoglobulins (IG) or antibodies with those expressed on B cells as part of BcR. We applied this strategy to define plasma IG and determine variable V gene usage after vaccination with the Plasmodium falciparum zygote antigen Pfs25. First, using proteomic tools coupled with bulk immunosequencing data, we determined human F(ab′)2 peptide sequences from plasma IG of adults who received four doses of Pfs25-EPA/Alhydrogel. Specifically, Pfs25 antigen-specific F(ab′)2 peptides (Pfs25-IG) were aligned to cDNA sequences of IGH complementarity determining region 3 (CDR3) from a dataset generated by total peripheral B cell immunosequencing of the entire vaccinated population. IGHV4 was the most commonly identified IGHV subgroup of Pfs25-IG, a pattern that was corroborated by VH/VL sequencing of Pfs25-specific single B cells from five vaccinees and by matching plasma Pfs25-IG peptides and V-(D)-J sequences of Pfs25-specific single B cells from the same donor. Among 13 recombinant human mAbs generated from IG sequences of Pfs25-specific single B cells, a single IGHV4 mAb displayed strong neutralizing activity, reducing the number of P. falciparum oocysts in infected mosquitoes by more than 80% at 100 μg/mL. Our approach characterizes the human plasma antibody repertoire in response to the Pfs25-EPA/Alhydrogel vaccine and will be useful to study circulating antibodies in response to other vaccines as well as those induced during infections or autoimmune disorders.
Authors
Camila H. Coelho, Steven T. Nadakal, Patricia A. Gonzales Hurtado, Robert Morrison, Jacob D. Galson, Jillian Neal, Yimin Wu, C. Richter King, Virginia Price, Kazutoyo Miura, Sharon Wong-Madden, Justin Y.A. Dortichamou, David L. Narum, Nicholas J. MacDonald, Maryonne Snow-Smith, Marissa Vignali, Justin J. Taylor, Marie-Paule Lefranc, Johannes Trück, Carole A. Long, Issaka Sagara, Michal Fried, Patrick E. Duffy
Abstract
Rapid and specific antibody testing is crucial for improved understanding, control, and treatment of COVID-19 pathogenesis. Herein, we describe and apply a rapid, sensitive, and accurate virus neutralization assay for SARS-CoV-2 antibodies. The new assay is based on an HIV-1 lentiviral vector that contains a secreted intron Gaussia luciferase or secreted Nano-luciferase reporter cassette, pseudotyped with the SARS-CoV-2 spike (S) glycoprotein, and is validated with a plaque reduction assay using an authentic, infectious SARS-CoV-2 strain. The new assay was used to evaluate SARS-CoV-2 antibodies in serum from individuals with a broad range of COVID-19 symptoms, including intensive care unit (ICU) patients, health care workers (HCWs), and convalescent plasma donors. The highest neutralizing antibody titers were observed among ICU patients, followed by general hospitalized patients, HCWs and convalescent plasma donors. Our study highlights a wide phenotypic variation in human antibody responses against SARS-CoV-2, and demonstrates the efficacy of a novel lentivirus pseudotype assay for high-throughput serological surveys of neutralizing antibody titers in large cohorts.
Authors
Cong Zeng, John P. Evans, Rebecca Pearson, Panke Qu, Yi-Min Zheng, Richard T. Robinson, Luanne Hall-Stoodley, Jacob S. Yount, Sonal Pannu, Rama K. Mallampalli, Linda Saif, Eugene Oltz, Gerard Lozanski, Shan-Lu Liu
Abstract
Patient-derived organoid models are proving to be a powerful platform for both basic and translational studies. Here we conduct a methodical analysis of pancreatic ductal adenocarcinoma (PDAC) tumor organoid drug response in paired PDX and PDX-derived organoid (PXO) models grown under WNT-free culture conditions. We report a specific relationship between Area Under the Curve value of organoid drug dose-response and in vivo tumor growth, irrespective of the drug treatment. In addition, we analyzed the glycome of PDX and PXO models and demonstrate that PXOs recapitulate the in vivo glycan landscape. In addition, we identify a core set of 57 N-glycans detected in all 10 models that represent 50-94% of the relative abundance of all N-glycans detected in each of the model. Lastly, we developed a secreted biomarker discovery pipeline using media supernatant of organoid cultures and identified potentially new extracellular vesicles (EV) protein markers. We validated our findings using plasma samples from patients with PDAC, benign gastrointestinal diseases, and chronic pancreatitis, and discover that four EV proteins are potential circulating biomarkers for PDAC. Thus, we demonstrate the utility of organoid cultures to not only model in vivo drug responses but also serve as a powerful platform for discovering clinically-actionable serologic biomarkers.
Authors
Ling Huang, Bruno Bockorny, Indranil Paul, Dipikaa Akshinthala, Pierre-Olivier Frappart, Omar Gandarilla, Arindam Bose, Veronica Sanchez-Gonzalez, Emily Rouse, Sylvain Lehoux, Nicole Pandell, Christine Lim, John G. Clohessy, Joseph E. Grossman, Raul S. Gonzalez, Sofia Perea, George Daaboul, Mandeep Sawhney, Steven D. Freedman, Alexander Kleger, Richard D. Cummings, Andrew Emili, Lakshmi Muthuswamy, Manuel Hidalgo, Senthil Muthuswamy
Abstract
Pre-existing humoral immunity to recombinant adeno-associated viral (AAV) vectors restricts the treatable patient population and efficacy of human gene therapies. Approaches to clear neutralizing antibodies (NAbs), such as plasmapheresis and immunosuppression are either ineffective or cause undesirable side effects. Here, we describe a clinically relevant strategy to rapidly and transiently degrade NAbs prior to AAV administration using an IgG degrading enzyme (IdeZ). We demonstrate that recombinant IdeZ efficiently cleaves IgG in dog, monkey and human antisera. Prophylactically administered IdeZ cleaves circulating, human IgG in mice and prevents AAV neutralization in vivo. In macaques, a single intravenous dose of IdeZ rescues AAV transduction by transiently reversing seropositivity. Importantly, IdeZ efficiently cleaves NAbs and rescues AAV transduction in mice passively immunized with individual human donor sera representing a diverse population. Our antibody clearance approach presents a new paradigm for expanding the prospective patient cohort and improving efficacy of AAV gene therapy.
Authors
Zachary C. Elmore, Daniel K. Oh, Katherine E. Simon, Marco M. Fanous, Aravind Asokan
Abstract
Identification of MHC class I bound peptides by immunopurification of MHC complexes and subsequent analysis by mass spectrometry is crucial for understanding T cell immunology and immunotherapy. Investigation of the steps for the MHC ligand isolation process revealed biases in widely used isolation techniques towards peptides of lower hydrophobicity. As MHC ligand hydrophobicity correlates positively with immunogenicity, identification of more hydrophobic MHC ligands could potentially lead to more effective isolation of immunogenic peptides as targets for immunotherapies. We solved this problem by use of higher concentrations of acetonitrile (ACN) for the separation of MHC ligands and their respective complexes. This increased overall MHC ligand identifications by 2-fold, detection of cancer germline antigen-derived peptides by 50%, and resulted in profound variations in isolation efficacy between different MHC alleles correlating with the hydrophobicity of their anchor residues. Overall, these insights enabled a more complete view on the immunopeptidome and overcame a systematic underrepresentation of these critical MHC ligands of high hydrophobicity.
Authors
Martin G. Klatt, Kyeara N. Mack, Yang Bai, Zita E.H. Aretz, Levy I. Nathan, Sung Soo Mun, Tao Dao, David A. Scheinberg
Abstract
In prior studies, we delineated the landscape of neoantigens arising from nonsynonymous point mutations in a murine pancreatic cancer model, Panc02. We developed a peptide vaccine by targeting neoantigens predicted using a pipeline that incorporates the MHC binding algorithm NetMHC. The vaccine, when combined with immune checkpoint modulators, elicited a robust neoepitope-specific antitumor immune response and led to tumor clearance. However, only a small fraction of the predicted neoepitopes induced T cell immunity, similarly to that reported for neoantigen vaccines tested in clinical studies. While these studies have used binding affinities to MHC I as surrogates for T cell immunity, this approach does not include spatial information on the mutated residue that is crucial for TCR activation. Here, we investigate conformational alterations in and around the MHC binding groove induced by selected minimal neoepitopes, and we examine the influence of a given mutated residue as a function of its spatial position. We found that structural parameters, including the solvent-accessible surface area (SASA) of the neoepitope and the position and spatial configuration of the mutated residue within the sequence, can be used to improve the prediction of immunogenic neoepitopes for inclusion in cancer vaccines.
Authors
Neeha Zaidi, Mariya Soban, Fangluo Chen, Heather Kinkead, Jocelyn Mathew, Mark Yarchoan, Todd D. Armstrong, Shozeb Haider, Elizabeth M. Jaffee
Abstract
Recently, we demonstrated that hematopoietic stem/progenitor cell (HSPC) mobilization followed by intravenous injection of integrating, helper-dependent adenovirus HDAd5/35++ vectors resulted in efficient transduction of long-term repopulating cells and disease amelioration in mouse models after in vivo selection of transduced HSPCs. Acute innate toxicity associated with HDAd5/35++ injection was controlled by appropriate prophylaxis, making this approach feasible for clinical translation. Our ultimate goal is to use this technically simple in vivo HSPC transduction approach for gene therapy of thalassemia major or sickle cell disease. A cure of these diseases requires high expression levels of the therapeutic protein (γ- or β-globin), which is difficult to achieve with lentivirus vectors because of their genome size limitation not allowing larger regulatory elements to be accommodated. Here, we capitalized on the 35 kb insert capacity of HDAd5/35++ vectors to demonstrate that transcriptional regulatory regions of the β-globin locus with a total length of 29 kb can efficiently be transferred into HSPCs. The in vivo HSPC transduction resulted in stable γ-globin levels in erythroid cells that conferred a complete cure of murine thalassemia intermedia. Notably, this was achieved with a minimal in vivo HSPC selection regimen.
Authors
Hongjie Wang, Aphrodite Georgakopoulou, Chang Li, Zhinan Liu, Sucheol Gil, Ashvin Bashyam, Evangelia Yannaki, Achilles Anagnostopoulos, Amit Pande, Zsuzsanna Izsvák, Thalia Papayannopoulou, André Lieber
Abstract
Detecting, characterizing, and monitoring rare populations of cells can increase testing sensitivity, give insight into disease mechanism, and inform clinical decision making. One area that can benefit from increased resolution is management of cancers in clinical remission but with measurable residual disease (MRD) by multicolor FACS. Detecting and monitoring genomic clonal resistance to treatment in the setting of MRD is technically difficult and resource intensive due to the limited amounts of disease cells. Here, we describe limited-cell FACS sequencing (LC-FACSeq), a reproducible, highly sensitive method of characterizing clonal evolution in rare cells relevant to different types of acute and chronic leukemias. We demonstrate the utility of LC-FACSeq for broad multigene gene panels and its application for monitoring sequential acquisition of mutations conferring therapy resistance and clonal evolution in long-term ibrutinib treatment of patients with chronic lymphocytic leukemia. This technique is generalizable for monitoring of other blood and marrow infiltrating cancers.
Authors
Eileen Y. Hu, James S. Blachly, Caner Saygin, Hatice G. Ozer, Stephanie E. Workman, Arletta Lozanski, Tzyy-Jye Doong, Chi-Ling Chiang, Seema Bhat, Kerry A. Rogers, Jennifer A. Woyach, Kevin R. Coombes, Daniel Jones, Natarajan Muthusamy, Gerard Lozanski, John C. Byrd
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