@article{tiruthani_cruz-teran_chan_ma_mcsweeney_wolf_yuan_poon_chan_botta_et al._2024, title={Engineering a "muco-trapping" ACE2-immunoglobulin hybrid with picomolar affinity as an inhaled, pan-variant immunotherapy for COVID-19}, ISSN={["2380-6761"]}, DOI={10.1002/btm2.10650}, abstractNote={Soluble angiotensin‐converting enzyme 2 (ACE2) can act as a decoy molecule that neutralizes severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) by blocking spike (S) proteins on virions from binding ACE2 on host cells. Based on structural insights of ACE2 and S proteins, we designed a “muco‐trapping” ACE2‐Fc conjugate, termed ACE2‐(G4S)6‐Fc, comprised of the extracellular segment of ACE2 (lacking the C‐terminal collectrin domain) that is linked to mucin‐binding IgG1‐Fc via an extended glycine‐serine flexible linker. ACE2‐(G4S)6‐Fc exhibits substantially greater binding affinity and neutralization potency than conventional full length ACE2‐Fc decoys or similar truncated ACE2‐Fc decoys without flexible linkers, possessing picomolar binding affinity and strong neutralization potency against pseudovirus and live virus. ACE2‐(G4S)6‐Fc effectively trapped fluorescent SARS‐CoV‐2 virus like particles in fresh human airway mucus and was stably nebulized using a commercial vibrating mesh nebulizer. Intranasal dosing of ACE2‐(G4S)6‐Fc in hamsters as late as 2 days postinfection provided a 10‐fold reduction in viral load in the nasal turbinate tissues by Day 4. These results strongly support further development of ACE2‐(G4S)6‐Fc as an inhaled immunotherapy for COVID‐19, as well as other emerging viruses that bind ACE2 for cellular entry.}, journal={BIOENGINEERING & TRANSLATIONAL MEDICINE}, author={Tiruthani, Karthik and Cruz-Teran, Carlos and Chan, Jasper F. W. and Ma, Alice and Mcsweeney, Morgan and Wolf, Whitney and Yuan, Shoufeng and Poon, Vincent K. M. and Chan, Chris C. S. and Botta, Lakshmi and et al.}, year={2024}, month={Feb} }
 @article{pearson_wessler_chen_boucher_freeman_lai_pickles_forest_2023, title={Modeling identifies variability in SARS-CoV-2 uptake and eclipse phase by infected cells as principal drivers of extreme variability in nasal viral load in the 48 h post infection}, volume={565}, ISSN={["1095-8541"]}, DOI={10.1016/j.jtbi.2023.111470}, abstractNote={The SARS-CoV-2 coronavirus continues to evolve with scores of mutations of the spike, membrane, envelope, and nucleocapsid structural proteins that impact pathogenesis. Infection data from nasal swabs, nasal PCR assays, upper respiratory samples, ex vivo cell cultures and nasal epithelial organoids reveal extreme variabilities in SARS-CoV-2 RNA titers within and between the variants. Some variabilities are naturally prone to clinical testing protocols and experimental controls. Here we focus on nasal viral load sensitivity arising from the timing of sample collection relative to onset of infection and from heterogeneity in the kinetics of cellular infection, uptake, replication, and shedding of viral RNA copies. The sources of between-variant variability are likely due to SARS-CoV-2 structural protein mutations, whereas within-variant population variability is likely due to heterogeneity in cellular response to that particular variant. With the physiologically faithful, agent-based mechanistic model of inhaled exposure and infection from (Chen et al., 2022), we perform statistical sensitivity analyses of the progression of nasal viral titers in the first 0-48 h post infection, focusing on three kinetic mechanisms. Model simulations reveal shorter latency times of infected cells (including cellular uptake, viral RNA replication, until the onset of viral RNA shedding) exponentially accelerate nasal viral load. Further, the rate of infectious RNA copies shed per day has a proportional influence on nasal viral load. Finally, there is a very weak, negative correlation of viral load with the probability of infection per virus-cell encounter, the model proxy for spike-receptor binding affinity.}, journal={JOURNAL OF THEORETICAL BIOLOGY}, author={Pearson, Jason and Wessler, Timothy and Chen, Alex and Boucher, Richard C. and Freeman, Ronit and Lai, Samuel K. and Pickles, Raymond and Forest, Gregory}, year={2023}, month={May} }
 @article{talkington_mcsweeney_wessler_rath_li_zhang_yuan_frank_forest_cao_et al._2022, title={A PBPK model recapitulates early kinetics of anti-PEG antibody-mediated clearance of PEG-liposomes}, volume={343}, ISSN={["1873-4995"]}, DOI={10.1016/j.jconrel.2022.01.022}, abstractNote={PEGylation is routinely used to extend the systemic circulation of various protein therapeutics and nanomedicines. Nonetheless, mounting evidence is emerging that individuals exposed to select PEGylated therapeutics can develop antibodies specific to PEG, i.e., anti-PEG antibodies (APA). In turn, APA increase both the risk of hypersensitivity to the drug as well as potential loss of efficacy due to accelerated blood clearance of the drug. Despite the broad implications of APA, the timescales and systemic specificity by which APA can alter the pharmacokinetics and biodistribution of PEGylated drugs remain not well understood. Here, we developed a physiologically based pharmacokinetic (PBPK) model designed to resolve APA's impact on both early- and late-phase pharmacokinetics and biodistribution of intravenously administered PEGylated drugs. Our model accurately recapitulates PK and biodistribution data obtained from PET/CT imaging of radiolabeled PEG-liposomes and PEG-uricase in mice with and without APA, as well as serum levels of PEG-uricase in humans. Our work provides another illustration of the power of high-resolution PBPK models for understanding the pharmacokinetic impacts of anti-drug antibodies and the dynamics with which antibodies can mediate clearance of foreign species.}, journal={JOURNAL OF CONTROLLED RELEASE}, author={Talkington, Anne M. and McSweeney, Morgan D. and Wessler, Timothy and Rath, Marielle K. and Li, Zibo and Zhang, Tao and Yuan, Hong and Frank, Jonathan E. and Forest, M. Gregory and Cao, Yanguang and et al.}, year={2022}, month={Mar}, pages={518–527} }
 @article{mcsweeney_stewart_richardson_kang_park_kim_tiruthani_wolf_schaefer_kumar_et al._2022, title={Stable nebulization and muco-trapping properties of regdanvimab/IN-006 support its development as a potent, dose-saving inhaled therapy for COVID-19}, ISSN={["2380-6761"]}, DOI={10.1002/btm2.10391}, abstractNote={The respiratory tract represents the key target for antiviral delivery in early interventions to prevent severe COVID-19. While neutralizing monoclonal antibodies (mAb) possess considerable efficacy, their current reliance on parenteral dosing necessitates very large doses and places a substantial burden on the healthcare system. In contrast, direct inhaled delivery of mAb therapeutics offers the convenience of self-dosing at home, as well as much more efficient mAb delivery to the respiratory tract. Here, building on our previous discovery of Fc-mucin interactions crosslinking viruses to mucins, we showed that regdanvimab, a potent neutralizing mAb already approved for COVID-19 in several countries around the world, can effectively trap SARS-CoV-2 virus-like-particles in fresh human airway mucus. IN-006, a reformulation of Regdanvimab, was stably nebulized across a wide range of concentrations, with no loss of activity and no formation of aggregates. Finally, nebulized delivery of IN-006 resulted in 100-fold greater mAb levels in the lungs of rats compared to serum, in marked contrast to intravenously dosed mAbs. These results not only support our current efforts to evaluate the safety and efficacy of IN-006 in clinical trials, but more broadly substantiate nebulized delivery of human antiviral mAbs as a new paradigm in treating SARS-CoV-2 and other respiratory pathologies.}, journal={BIOENGINEERING & TRANSLATIONAL MEDICINE}, author={McSweeney, Morgan and Stewart, Ian and Richardson, Zach and Kang, Hyunah and Park, Yoona and Kim, Cheolmin and Tiruthani, Karthik and Wolf, Whitney and Schaefer, Alison and Kumar, Priya and et al.}, year={2022}, month={Aug} }
 @article{huckaby_landoni_jacobs_savoldo_dotti_lai_2021, title={Bispecific binder redirected lentiviral vector enables in vivo engineering of CAR-T cells}, volume={9}, ISSN={["2051-1426"]}, DOI={10.1136/jitc-2021-002737}, abstractNote={Background Chimeric antigen receptor (CAR) T cells have shown considerable promise as a personalized cellular immunotherapy against B cell malignancies. However, the complex and lengthy manufacturing processes involved in generating CAR T cell products ex vivo result in substantial production time delays and high costs. Furthermore, ex vivo expansion of T cells promotes cell differentiation that reduces their in vivo replicative capacity and longevity. Methods Here, to overcome these limitations, CAR-T cells are engineered directly in vivo by administering a lentivirus expressing a mutant Sindbis envelope, coupled with a bispecific antibody binder that redirects the virus to CD3+ human T cells. Results This redirected lentiviral system offers exceptional specificity and efficiency; a single dose of the virus delivered to immunodeficient mice engrafted with human peripheral blood mononuclear cells generates CD19-specific CAR-T cells that markedly control the growth of an aggressive pre-established xenograft B cell tumor. Conclusions These findings underscore in vivo engineering of CAR-T cells as a promising approach for personalized cancer immunotherapy.}, number={9}, journal={JOURNAL FOR IMMUNOTHERAPY OF CANCER}, author={Huckaby, Justin T. and Landoni, Elisa and Jacobs, Timothy M. and Savoldo, Barbara and Dotti, Gianpietro and Lai, Samuel K.}, year={2021}, month={Sep} }
 @misc{cruz-teran_tiruthani_mcsweeney_ma_pickles_lai_2021, title={Challenges and opportunities for antiviral monoclonal antibodies as COVID-19 therapy}, volume={169}, ISSN={["1872-8294"]}, DOI={10.1016/j.addr.2020.12.004}, abstractNote={To address the COVID-19 pandemic, there has been an unprecedented global effort to advance potent neutralizing mAbs against SARS-CoV-2 as therapeutics. However, historical efforts to advance antiviral monoclonal antibodies (mAbs) for the treatment of other respiratory infections have been met with categorical failures in the clinic. By investigating the mechanism by which SARS-CoV-2 and similar viruses spread within the lung, along with available biodistribution data for systemically injected mAb, we highlight the challenges faced by current antiviral mAbs for COVID-19. We summarize some of the leading mAbs currently in development, and present the evidence supporting inhaled delivery of antiviral mAb as an early intervention against COVID-19 that could prevent important pulmonary morbidities associated with the infection.}, journal={ADVANCED DRUG DELIVERY REVIEWS}, author={Cruz-Teran, Carlos and Tiruthani, Karthik and McSweeney, Morgan and Ma, Alice and Pickles, Raymond and Lai, Samuel K.}, year={2021}, month={Feb}, pages={100–117} }
 @article{shrestha_schaefer_zhu_saada_jacobs_chavez_omsted_cruz-teran_vaca_vincent_et al._2021, title={Engineering sperm-binding IgG antibodies for the development of an effective nonhormonal female contraception}, volume={13}, ISSN={["1946-6242"]}, DOI={10.1126/scitranslmed.abd5219}, abstractNote={A panel of anti-sperm IgGs that effectively agglutinate human sperm in vitro and in sheep has been developed for nonhormonal contraception. Stopping sperm in its tracks Many women have contraindications to or are dissatisfied with hormone-based birth control. Here, Shrestha and colleagues developed a panel of sperm-binding antibodies based on an immunoglobulin against human sperm isolated from an infertile woman. By engineering the antibodies to contain additional antigen-binding fragments while maintaining the portion of the IgG that mediates trapping of sperm, the authors generated a panel of highly multivalent IgGs (HM-IgGs) that were substantially more potent and faster at agglutinating sperm than the original IgG in vitro and effectively reduced progressively motile sperm in the sheep vagina. Although tests in humans are needed, these HM-IgGs may offer women another alternative to hormonal contraception. Many women risk unintended pregnancy because of medical contraindications or dissatisfaction with contraceptive methods, including real and perceived side effects associated with the use of exogenous hormones. We pursued direct vaginal delivery of sperm-binding monoclonal antibodies (mAbs) that can limit progressive sperm motility in the female reproductive tract as a strategy for effective nonhormonal contraception. Here, motivated by the greater agglutination potencies of polyvalent immunoglobulins but the bioprocessing ease and stability of immunoglobulin G (IgG), we engineered a panel of sperm-binding IgGs with 6 to 10 antigen-binding fragments (Fabs), isolated from a healthy immune-infertile woman against a unique surface antigen universally present on human sperm. These highly multivalent IgGs (HM-IgGs) were at least 10- to 16-fold more potent and faster at agglutinating sperm than the parent IgG while preserving the crystallizable fragment (Fc) of IgG that mediates trapping of individual spermatozoa in mucus. The increased potencies translated into effective (>99.9%) reduction of progressively motile sperm in the sheep vagina using as little as 33 μg of the 10-Fab HM-IgG. HM-IgGs were produced at comparable yields and had identical thermal stability to the parent IgG, with greater homogeneity. HM-IgGs represent not only promising biologics for nonhormonal contraception but also a promising platform for engineering potent multivalent mAbs for other biomedical applications.}, number={606}, journal={SCIENCE TRANSLATIONAL MEDICINE}, author={Shrestha, Bhawana and Schaefer, Alison and Zhu, Yong and Saada, Jamal and Jacobs, Timothy M. and Chavez, Elizabeth C. and Omsted, Stuart S. and Cruz-Teran, Carlos A. and Vaca, Gabriela Baldeon and Vincent, Kathleen and et al.}, year={2021}, month={Aug} }
 @article{talkington_wessler_lai_cao_forest_2021, title={Experimental Data and PBPK Modeling Quantify Antibody Interference in PEGylated Drug Carrier Delivery}, volume={83}, ISSN={["1522-9602"]}, DOI={10.1007/s11538-021-00950-z}, abstractNote={Physiologically-based pharmacokinetic (PBPK) modeling is a popular drug development tool that integrates physiology, drug physicochemical properties, preclinical data, and clinical information to predict drug systemic disposition. Since PBPK models seek to capture complex physiology, parameter uncertainty and variability is a prevailing challenge: there are often more compartments (e.g., organs, each with drug flux and retention mechanisms, and associated model parameters) than can be simultaneously measured. To improve the fidelity of PBPK modeling, one approach is to search and optimize within the high-dimensional model parameter space, based on experimental time-series measurements of drug distributions. Here, we employ Latin Hypercube Sampling (LHS) on a PBPK model of PEG-liposomes (PL) that tracks biodistribution in an 8-compartment mouse circulatory system, in the presence (APA+) or absence (naïve) of anti-PEG antibodies (APA). Near-continuous experimental measurements of PL concentration during the first hour post-injection from the liver, spleen, kidney, muscle, lung, and blood plasma, based on PET/CT imaging in live mice, are used as truth sets with LHS to infer optimal parameter ranges for the full PBPK model. The data and model quantify that PL retention in the liver is the primary differentiator of biodistribution patterns in naïve versus APA+ mice, and spleen the secondary differentiator. Retention of PEGylated nanomedicines is substantially amplified in APA+ mice, likely due to PL-bound APA engaging specific receptors in the liver and spleen that bind antibody Fc domains. Our work illustrates how applying LHS to PBPK models can further mechanistic understanding of the biodistribution and antibody-mediated clearance of specific drugs.}, number={12}, journal={BULLETIN OF MATHEMATICAL BIOLOGY}, author={Talkington, Anne M. and Wessler, Timothy and Lai, Samuel K. and Cao, Yanguang and Forest, M. Gregory}, year={2021}, month={Dec} }
 @article{talkington_mcsweeney_zhang_li_nyborg_lamoreaux_livingston_frank_yuan_lai_2021, title={High MW polyethylene glycol prolongs circulation of pegloticase in mice with anti-PEG antibodies}, volume={338}, ISSN={["1873-4995"]}, DOI={10.1016/j.jconrel.2021.08.051}, abstractNote={Pegloticase is an enzyme used to reduce serum uric acid levels in patients with chronic, treatment-refractory gout. Clinically, about 40% of patients develop high titers of anti-PEG antibodies (APA) after initial treatment, which in turn quickly eliminate subsequent doses of pegloticase from the systemic circulation and render the treatment ineffective. We previously found that pre-infusion with high MW free PEG (40 kDa) can serve as a decoy to saturate circulating APA, preventing binding to a subsequently administered dose of PEG-liposomes and restoring their prolonged circulation in mice, without any detectible toxicity. Here, we investigated the use of 40 kDa free PEG to restore the circulation of radio-labeled pegloticase in mice using longitudinal Positron Emission Tomography (PET) imaging over 4 days. Mice injected with pegloticase developed appreciable APA titers by Day 9, which further increased through Day 14. Compared to naïve mice, mice with pegloticase-induced APA rapidly cleared 89Zr-labeled pegloticase, with ~75% lower pegloticase concentrations in the circulation at four hours after treatment. The 96-h AUC in APA+ mice was less than 30% of the AUC in naïve mice. In contrast, pre-infusion of free PEG into PEG-sensitized mice restored the AUC of pegloticase to ~80% of that seen in naïve mice, resulting in a similar biodistribution to pegloticase in naïve mice over time. These results suggest that pre-infusion of free PEG may be a promising strategy to enable the safe and efficacious use of pegloticase and other PEGylated drugs in patients that have previously failed therapy due to induced APA.}, journal={JOURNAL OF CONTROLLED RELEASE}, author={Talkington, Anne M. and McSweeney, Morgan D. and Zhang, Tao and Li, Zibo and Nyborg, Andrew C. and LaMoreaux, Brian and Livingston, Eric W. and Frank, Jonathan E. and Yuan, Hong and Lai, Samuel K.}, year={2021}, month={Oct}, pages={804–812} }
 @article{lai_mcsweeney_pickles_2021, title={Learning from past failures: Challenges with monoclonal antibody therapies for COVID-19}, volume={329}, ISSN={["1873-4995"]}, DOI={10.1016/j.jconrel.2020.11.057}, abstractNote={COVID-19, the disease caused by infection with SARS-CoV-2, requires urgent development of therapeutic interventions. Due to their safety, specificity, and potential for rapid advancement into the clinic, monoclonal antibodies (mAbs) represent a highly promising class of antiviral or anti-inflammatory agents. Herein, by analyzing prior efforts to advance antiviral mAbs for other acute respiratory infections (ARIs), we highlight the challenges faced by mAb-based immunotherapies for COVID-19. We present evidence supporting early intervention immediately following a positive diagnosis via inhaled delivery of mAbs with vibrating mesh nebulizers as a promising approach for the treatment of COVID-19.}, journal={JOURNAL OF CONTROLLED RELEASE}, author={Lai, Samuel K. and McSweeney, Morgan D. and Pickles, Raymond J.}, year={2021}, month={Jan}, pages={87–95} }
 @article{mcsweeney_shen_dewalle_joiner_ciociola_raghuwanshi_macauley_lai_2021, title={Pre-treatment with high molecular weight free PEG effectively suppresses anti-PEG antibody induction by PEG-liposomes in mice}, volume={329}, ISSN={["1873-4995"]}, DOI={10.1016/j.jconrel.2020.10.011}, abstractNote={Immune responses against polyethylene glycol (PEG) can lead to the rapid clearance of PEGylated drugs and are associated with increased risk of serious adverse events such as infusion reactions and anaphylaxis. Although select PEGylated therapeutics can induce anti-PEG antibodies (APA), there is currently no readily deployable strategy to mitigate their negative effects. Given the large number of PEGylated therapeutics that are either FDA-approved or in clinical development, methods that suppress APA induction to ensure the safety and efficacy of PEGylated drugs in patients would be a valuable clinical tool. We previously showed that infusion of high molecular weight (MW) free PEG can safely and effectively restore the circulation of PEG liposomes in animals with high pre-existing titers of APA, without stimulating additional APA production. Here, we explored the effectiveness of prophylaxis with free PEG or tolerogenic PEGylated liposomes as a strategy to reduce the amount of APA induced by subsequently administered PEGylated liposomes. Surprisingly, we found that a single administration of free PEG alone was capable of markedly reducing the APA response to PEG-liposomes for ~2 months; the effectiveness was comparable to, and frequently exceeded, interventions with different tolerogenic PEG-liposomes. These results support further investigations of free PEG prophylaxis as a potential strategy to ameliorate the APA response to sensitizing PEGylated therapeutics.}, journal={JOURNAL OF CONTROLLED RELEASE}, author={McSweeney, Morgan D. and Shen, Limei and DeWalle, Alexander C. and Joiner, Jordan B. and Ciociola, Elizabeth C. and Raghuwanshi, Dharmendra and Macauley, Matthew S. and Lai, Samuel K.}, year={2021}, month={Jan}, pages={774–781} }
 @article{schaefer_lai_2021, title={The biophysical principles underpinning muco-trapping functions of antibodies}, ISSN={["2164-554X"]}, DOI={10.1080/21645515.2021.1939605}, abstractNote={ABSTRACT In addition to the classical immunological functions such as neutralization, antibody-dependent cellular cytotoxicity, and complement activation, IgG antibodies possess a little-recognized and under-utilized effector function at mucosal surfaces: trapping pathogens in mucus. IgG can potently immobilize pathogens that otherwise readily diffuse or actively swim through mucus by forming multiple low-affinity bonds between the array of pathogen-bound antibodies and the mucin mesh. Trapping in mucus can exclude pathogens from contacting target cells, and facilitate their rapid elimination by natural mucus clearance mechanisms. Despite the fact that most infections are transmitted at mucosal surfaces, this muco-trapping effector function has only been revealed within the past decade, with the evidence to date suggesting that it is a universal effector function of IgG-Fc capable of immobilizing both viral and highly motile bacterial pathogens in all major mucosal secretions. This review provides an overview of the current evidence for Fc-mucin crosslinking as an effector function for antibodies in mucus, the mechanism by which the accumulation of weak Fc-mucin bonds by IgG bound to the surface of a pathogen can result in immobilization of antibody-pathogen complexes, and how trapping in mucus can contribute to protection against foreign pathogens.}, journal={HUMAN VACCINES & IMMUNOTHERAPEUTICS}, author={Schaefer, Alison and Lai, Samuel K.}, year={2021}, month={Jun} }
 @article{schiller_fogle_bussey_kissner_hill_lai_2020, title={Antibody-mediated trapping in biological hydrogels is governed by sugar-sugar hydrogen bonds}, volume={107}, ISSN={["1878-7568"]}, DOI={10.1016/j.actbio.2020.03.002}, abstractNote={N-glycans on IgG and IgM antibodies (Ab) facilitate Ab-mediated crosslinking of viruses and nanoparticles to the major structural elements of mucus and basement membranes. Nevertheless, the chemical moieties in these biological hydrogel matrices to which Ab can bind remain poorly understood. To gain insights into the chemistries that support Ab-matrix interactions, we systematically evaluated IgG- and IgM-mediated trapping of nanoparticles in different polysaccharide-based biogels with unique chemical features. In agarose, composed of alternating d-galactose and 3,6-anhydro-l-galactopyranose (i.e. hydroxyl groups only), anti-PEG IgM but not anti-PEG IgG trapped PEGylated nanoparticles. In alginate, comprised of homopolymeric blocks of mannuronate and guluronate (i.e. both hydroxyl and carboxyl groups), both IgG and IgM trapped PEGylated nanoparticles. In contrast, chitosan, comprised primarily of glucosamine (i.e. both hydroxyl and primary amine groups), did not facilitate either IgG- or IgM-mediated trapping. IgG-mediated trapping in alginate was abrogated upon removal of IgG N-glycans, whereas IgM-mediated trapping was eliminated in agarose but not alginate upon desialylation. These results led us to propose a model in which hydrogen bonding between carboxyl and hydroxyl groups of glycans on both Ab and matrix facilitates Ab-mediated trapping of pathogens in biogels. Our work here offers a blueprint for designing de novo hydrogels that could harness Ab-matrix interactions for various biomedical and biological applications. STATEMENT OF SIGNIFICANCE: Here, we interrogated the molecular mechanism of antibody-mediated trapping to address what are the chemical moieties on biogels that are essential for facilitating trapping in biogels. We systematically evaluated the potencies of IgG and IgM to trap nanoparticles in different polysaccharide-based biogels with unique and highly defined chemical moieties: hydroxyl groups (agarose), amine groups (chitosan), and carboxyl groups (alginate). We discovered that only hydroxyl/carboxyl hydrogen bonds (and stronger) are sufficiently strong enough to facilitate antibody-mediated trapping; weaker hydroxyl/hydroxyl bonds or hydroxyl/amine bonds fail to adequately slow particles. Our findings presents the first blueprint for how to engineer de novo biogels that are capable of harnessing antibodies to immobilize foreign entities in the biogels, for applications ranging from infectious disease to contraception to purification processes.}, journal={ACTA BIOMATERIALIA}, author={Schiller, Jennifer L. and Fogle, Mary M. and Bussey, Olivia and Kissner, William J. and Hill, David B. and Lai, Samuel K.}, year={2020}, month={Apr}, pages={91–101} }
 @misc{voorhees_cruz-teran_edelstein_lai_2020, title={Challenges & opportunities for phage-based in situ microbiome engineering in the gut}, volume={326}, ISSN={["1873-4995"]}, DOI={10.1016/j.jconrel.2020.06.016}, abstractNote={The gut microbiome is a promising target for the development of GI tract therapies, yet it has been under-exploited due, in part, to a lack of tools to control and manipulate complex microbial communities. To date, the most common approach in harnessing bacteria for therapeutic purposes has been to deliver ex vivo engineered bacteria—effectively taking a bacterial cell therapy-based approach. An alternative approach involves taking advantage of the rich microbial ecosystem in the gut by genetically modifying the microbiome in situ through the use of engineered bacteriophages—akin to human gene therapies delivered by viral vectors. In this review, we present the challenges and opportunities associated with engineering bacteriophages to control and manipulate the gut microbiome.}, journal={JOURNAL OF CONTROLLED RELEASE}, author={Voorhees, Peter J. and Cruz-Teran, Carlos and Edelstein, Jasmine and Lai, Samuel K.}, year={2020}, month={Oct}, pages={106–119} }
 @article{shrestha_schaefer_chavez_kopp_jacobs_moench_lai_2020, title={Engineering tetravalent IgGs with enhanced agglutination potencies for trapping vigorously motile sperm in mucin matrix}, volume={117}, ISSN={["1878-7568"]}, DOI={10.1016/j.actbio.2020.09.020}, abstractNote={Multivalent antibodies such as sIgA can crosslink motile entities such as sperm and bacteria, creating agglomerates that are too large to permeate the dense mucin matrix in mucus, a process commonly referred to as immune exclusion. Unfortunately, sIgA remains challenging to produce in large quantities, and easily aggregates, which prevented their use in clinical applications. To develop sIgA-like tetravalent antibodies that are stable and can be easily produced in large quantities, we designed two IgGs possessing 4 identical Fab domains, with the Fabs arranged either in serial or in the diametrically opposite orientation. As a proof-of-concept, we engineered these tetravalent IgG constructs to bind a ubiquitous sperm antigen using a Fab previously isolated from an immune infertile woman. Both constructs possess at least 4-fold greater agglutination potency and induced much more rapid sperm agglutination than the parent IgG, while exhibiting comparable production yields and identical thermostability as the parent IgG. These tetravalent IgGs offer promise for non-hormonal contraception and underscores the multimerization of IgG as a promising strategy to enhance antibody effector functions based on immune exclusion.}, journal={ACTA BIOMATERIALIA}, author={Shrestha, Bhawana and Schaefer, Alison and Chavez, Elizabeth C. and Kopp, Alexander J. and Jacobs, Timothy M. and Moench, Thomas R. and Lai, Samuel K.}, year={2020}, month={Nov}, pages={226–234} }
 @article{schroeder_newby_schaefer_subramani_tubbs_gregory forest_miao_lai_2020, title={LPS-binding IgG arrests actively motile Salmonella Typhimurium in gastrointestinal mucus}, volume={13}, ISSN={["1935-3456"]}, DOI={10.1038/s41385-020-0267-9}, abstractNote={The gastrointestinal (GI) mucosa is coated with a continuously secreted mucus layer that serves as the first line of defense against invading enteric bacteria. We have previously shown that antigen-specific immunoglobulin G (IgG) can immobilize viruses in both human airway and genital mucus secretions through multiple low-affinity bonds between the array of virion-bound IgG and mucins, thereby facilitating their rapid elimination from mucosal surfaces and preventing mucosal transmission. Nevertheless, it remains unclear whether weak IgG-mucin crosslinks could reinforce the mucus barrier against the permeation of bacteria driven by active flagella beating, or in predominantly MUC2 mucus gel. Here, we performed high-resolution multiple particle tracking to capture the real-time motion of hundreds of individual fluorescent Salmonella Typhimurium in fresh, undiluted GI mucus from Rag1-/- mice, and analyzed the motion using a hidden Markov model framework. In contrast to control IgG, the addition of anti-lipopolysaccharide IgG to GI mucus markedly reduced the progressive motility of Salmonella by lowering the swim speed and retaining individual bacteria in an undirected motion state. Effective crosslinking of Salmonella to mucins was dependent on Fc N-glycans. Our findings implicate IgG-mucin crosslinking as a broadly conserved function that reduces mucous penetration of both bacterial and viral pathogens.}, number={5}, journal={MUCOSAL IMMUNOLOGY}, author={Schroeder, Holly A. and Newby, Jay and Schaefer, Alison and Subramani, Babu and Tubbs, Alan and Gregory Forest, M. and Miao, Ed and Lai, Samuel K.}, year={2020}, month={Sep}, pages={814–823} }
 @article{huckaby_jacobs_li_perna_wang_nicely_lai_2020, title={Structure of an anti-PEG antibody reveals an open ring that captures highly flexible PEG polymers}, volume={3}, ISSN={["2399-3669"]}, DOI={10.1038/s42004-020-00369-y}, abstractNote={Polyethylene glycol (PEG) is a polymer routinely used to modify biologics and nanoparticles to prolong blood circulation and reduce immunogenicity of the underlying therapeutic. However, several PEGylated therapeutics induce the development of anti-PEG antibodies (APA), leading to reduced efficacy and increased adverse events. Given the highly flexible structure of PEG, how APA specifically bind PEG remains poorly understood. Here, we report a crystal structure illustrating the structural properties and conformation of the APA 6-3 Fab bound to the backbone of PEG. The structure reveals an open ring-like sub-structure in the Fab paratope, whereby PEG backbone is captured and then stabilized via Van der Waals interactions along the interior and exterior of the ring paratope surface. Our finding illustrates a strategy by which antibodies can bind highly flexible repeated structures that lack fixed conformations, such as polymers. This also substantially advances our understanding of the humoral immune response generated against PEG.}, number={1}, journal={COMMUNICATIONS CHEMISTRY}, author={Huckaby, Justin T. and Jacobs, Tim M. and Li, Zhongbo and Perna, Robert J. and Wang, Anting and Nicely, Nathan I and Lai, Samuel K.}, year={2020}, month={Sep} }
 @article{hoang_toler_delong_mafunda_bloom_zierden_moench_coleman_hanes_kwon_et al._2020, title={The cervicovaginal mucus barrier to HIV-1 is diminished in bacterial vaginosis}, volume={16}, ISSN={["1553-7374"]}, DOI={10.1371/journal.ppat.1008236}, abstractNote={Bacterial vaginosis (BV), a condition in which the vaginal microbiota consists of community of obligate and facultative anaerobes rather than dominated by a single species of Lactobacillus, affects ~30% of women in the US. Women with BV are at 60% increased risk for HIV acquisition and are 3-times more likely to transmit HIV to an uninfected partner. As cervicovaginal mucus (CVM) is the first line of defense against mucosal pathogens and the home of the resident vaginal microbiota, we hypothesized the barrier function of CVM to HIV may be diminished in BV. Here, we characterized CVM properties including pH, lactic acid content, and Nugent score to correlate with the microbiota community composition, which was confirmed by 16S rDNA sequencing on a subset of samples. We then quantified the mobility of fluorescently-labeled HIV virions and nanoparticles to characterize the structural and adhesive barrier properties of CVM. Our analyses included women with Nugent scores categorized as intermediate (4–6) and BV (7–10), women that were either symptomatic or asymptomatic, and a small group of women before and after antibiotic treatment for symptomatic BV. Overall, we found that HIV virions had significantly increased mobility in CVM from women with BV compared to CVM from women with Lactobacillus crispatus-dominant microbiota, regardless of whether symptoms were present. We confirmed using nanoparticles and scanning electron microscopy that the impaired barrier function was due to reduced adhesive barrier properties without an obvious degradation of the physical CVM pore structure. We further confirmed a similar increase in HIV mobility in CVM from women with Lactobacillus iners-dominant microbiota, the species most associated with transitions to BV and that persists after antibiotic treatment for BV. Our findings advance the understanding of the protective role of mucus and highlight the interplay between vaginal microbiota and the innate barrier function mucus.}, number={1}, journal={PLOS PATHOGENS}, author={Hoang, Thuy and Toler, Emily and DeLong, Kevin and Mafunda, Nomfuneko A. and Bloom, Seth M. and Zierden, Hannah C. and Moench, Thomas R. and Coleman, Jenell S. and Hanes, Justin and Kwon, Douglas S. and et al.}, year={2020}, month={Jan} }
 @misc{schiller_lai_2020, title={Tuning Barrier Properties of Biological Hydrogels}, volume={3}, ISSN={["2576-6422"]}, DOI={10.1021/acsabm.0c00187}, abstractNote={A major function of biological hydrogels (biogels) is to serve as barriers against invading pathogens and foreign materials. This review focuses on methods to tune the steric and adhesive barrier properties of biogels at the nanoscale. Altering the biogel mesh spacings that lead to changes in steric obstruction allows for gross exclusion of larger particles but does not provide selectivity with molecular specificity. Enabling direct binding of specific entities to the biogel microstructure introduces specificity yet has very limited breadth, unable to block numerous diverse entities. In contrast, third party modulators that interact with the biogel matrix to enable cross-linking of specific entities to the biogel mesh, or facilitate agglutination of these entities, can robustly tune the barrier properties of biogels against multiple species with molecular specificity without direct chemical modification of the biogel or changes to its microstructure. We review here the design requirements for developing effective third party modulators. The ability to selectively enhance the barrier properties of biogels has important implications for numerous applications including prevention of infection and contraception.}, number={5}, journal={ACS APPLIED BIO MATERIALS}, author={Schiller, Jennifer L. and Lai, Samuel K.}, year={2020}, month={May}, pages={2875–2890} }
 @article{huckaby_parker_jacobs_schaefer_wadsworth_nguyen_wang_newby_lai_2019, title={Engineering Polymer-Binding Bispecific Antibodies for Enhanced Pretargeted Delivery of Nanoparticles to Mucus-Covered Epithelium}, volume={58}, ISSN={["1521-3773"]}, DOI={10.1002/anie.201814665}, abstractNote={Mucus represents a major barrier to sustained and targeted drug delivery to mucosal epithelium. Ideal drug carriers should not only rapidly diffuse across mucus, but also bind the epithelium. Unfortunately, ligand-conjugated particles often exhibit poor penetration across mucus. In this work, we explored a two-step "pretargeting" approach through engineering a bispecific antibody that binds both cell-surface ICAM-1 and polyethylene glycol (PEG) on the surface of nanoparticles, thereby effectively decoupling cell targeting from particle design and formulation. When tested in a mucus-coated Caco-2 culture model that mimics the physiological process of mucus clearance, pretargeting increased the amount of PEGylated particles binding to cells by around 2-fold or more compared to either non-targeted or actively targeted PEGylated particles. Pretargeting also markedly enhanced particle retention in mouse intestinal tissues. Our work underscores pretargeting as a promising strategy to improve the delivery of therapeutics to mucosal surfaces.}, number={17}, journal={ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, author={Huckaby, Justin T. and Parker, Christina L. and Jacobs, Tim M. and Schaefer, Alison and Wadsworth, Daniel and Nguyen, Alexander and Wang, Anting and Newby, Jay and Lai, Samuel K.}, year={2019}, month={Apr}, pages={5604–5608} }
 @article{patel_mao_forest_lai_newby_2019, title={Limited processivity of single motors improves overall transport flux of self-assembled motor-cargo complexes}, volume={100}, ISSN={["2470-0053"]}, DOI={10.1103/PhysRevE.100.022408}, abstractNote={Single kinesin molecular motors can processively move along a microtubule (MT) a few micrometers on average before dissociating. However, cellular length scales over which transport occurs are several hundred microns and more. Why seemingly unreliable motors are used to transport cellular cargo remains poorly understood. We propose a theory for how low processivity, the average length of a single bout of directed motion, can enhance cellular transport when motors and cargos must first diffusively self-assemble into complexes. We employ stochastic modeling to determine the effect of processivity on overall cargo transport flux. We show that, under a wide range of physiologically relevant conditions, possessing "infinite" processivity does not maximize flux along MTs. Rather, we find that lowering processivity, i.e., weaker binding of motors to MTs, can improve transport flux. These results shed light on the relationship between processivity and transport efficiency and offer a theory for the physiological benefits of low motor processivity.}, number={2}, journal={PHYSICAL REVIEW E}, author={Patel, Keshav B. and Mao, Shengtan and Forest, M. Gregory and Lai, Samuel K. and Newby, Jay M.}, year={2019}, month={Aug} }
 @article{xu_newby_schiller_schroeder_wessler_chen_forest_lai_2019, title={Modeling Barrier Properties of Intestinal Mucus Reinforced with IgG and Secretory IgA against Motile Bacteria}, volume={5}, ISSN={["2373-8227"]}, DOI={10.1021/acsinfecdis.9b00109}, abstractNote={The gastrointestinal (GI) tract is lined with a layer of viscoelastic mucus gel, characterized by a dense network of entangled and cross-linked mucins together with an abundance of antibodies (Ab). Secretory IgA (sIgA), the predominant Ab isotype in the GI tract, is a dimeric molecule with 4 antigen-binding domains capable of inducing efficient clumping of bacteria, or agglutination. IgG, another common Ab at mucosal surfaces, can cross-link individual viruses to the mucin mesh through multiple weak bonds between IgG-Fc and mucins, a process termed muco-trapping. Relative contributions by agglutination versus muco-trapping in blocking permeation of motile bacteria through mucus remain poorly understood. Here, we developed a mathematical model that takes into account physiologically relevant spatial dimensions and time scales, binding and unbinding rates between Ab and bacteria as well as between Ab and mucins, the diffusivities of Ab, and run-tumble motion of active bacteria. Our model predicts both sIgA and IgG can accumulate on the surface of individual bacteria at sufficient quantities and rates to enable trapping individual bacteria in mucins before they penetrate the mucus layer. Furthermore, our model predicts that agglutination only modestly improves the ability for antibodies to block bacteria permeation through mucus. These results suggest that while sIgA is the most potent Ab isotype overall at stopping bacterial penetration, IgG may represent a practical alternative for mucosal prophylaxis and therapy. Our work improves the mechanistic understanding of Ab-enhanced barrier properties of mucus and highlights the ability for muco-trapping Ab to protect against motile pathogens at mucosal surfaces.}, number={9}, journal={ACS INFECTIOUS DISEASES}, author={Xu, Feifei and Newby, Jay M. and Schiller, Jennifer L. and Schroeder, Holly A. and Wessler, Timothy and Chen, Alex and Forest, M. Gregory and Lai, Samuel K.}, year={2019}, month={Sep}, pages={1570–1580} }
 @article{mcsweeney_price_wessler_ciociola_herity_piscitelli_dewalle_harris_chan_saw_et al._2019, title={Overcoming anti-PEG antibody mediated accelerated blood clearance of PEGylated liposomes by pre-infusion with high molecular weight free PEG}, volume={311}, ISSN={["1873-4995"]}, DOI={10.1016/j.jconrel.2019.08.017}, abstractNote={Antibodies that specifically bind polyethylene glycol (PEG), i.e. anti-PEG antibodies (APA), are associated with reduced efficacy and increased risk of serious adverse events for several PEGylated therapeutics. Here, we explored the concept of using free PEG molecules to saturate circulating APA. Surprisingly, we found that 40 kDa free PEG effectively restored the prolonged circulation of PEGylated liposomes in the presence of high titers of pre-existing APA for at least 48 h in mice. In contrast, lower molecular weight free PEG (≤10 kDa) failed to restore circulation beyond a few hours. These in vivo results were consistent with estimates from a minimal physiologically based pharmacokinetic model. Importantly, the infusion of free PEG appeared to be safe in mice previously sensitized by injection of PEGylated liposomes, and free PEG did not elicit excess APA production even in mice with pre-existing adaptive immunity against PEG. Our results support further investigation of high molecular weight free PEG as a potential method to control and overcome high titers of APA, restoring the prolonged circulation of PEGylated liposomes and possibly other PEGylated therapeutics.}, journal={JOURNAL OF CONTROLLED RELEASE}, author={McSweeney, Morgan D. and Price, Lauren S. L. and Wessler, Timothy and Ciociola, Elizabeth C. and Herity, Leah B. and Piscitelli, Joseph A. and DeWalle, Alexander C. and Harris, Taylor N. and Chan, Andy K. P. and Saw, Ran Sing and et al.}, year={2019}, month={Oct}, pages={138–146} }
 @article{schiller_marvin_mccallen_lai_2019, title={Robust antigen-specific tuning of the nanoscale barrier properties of biogels using matrix-associating IgG and IgM antibodies}, volume={89}, ISSN={["1878-7568"]}, DOI={10.1016/j.actbio.2019.03.023}, abstractNote={Biological hydrogels (biogels) are selective barriers that restrict passage of harmful substances yet allow the rapid movement of nutrients and select cells. Current methods to modulate the barrier properties of biogels typically involve bulk changes in order to restrict diffusion by either steric hindrance or direct high-affinity interactions with microstructural constituents. Here, we introduce a third mechanism, based on antibody-based third party anchors that bind specific foreign species but form only weak and transient bonds with biogel constituents. The weak affinity to biogel constituents allows antibody anchors to quickly accumulate on the surface of specific foreign species and facilitates immobilization via multiple crosslinks with the biogel matrix. Using the basement membrane Matrigel® and a mixture of laminin/entactin, we demonstrate that antigen-specific, but not control, IgG and IgM efficiently immobilize a variety of individual nanoparticles. The addition of Salmonella typhimurium-binding IgG to biogel markedly reduced the invasion of these highly motile bacteria. These results underscore a generalized strategy through which the barrier properties of biogels can be readily tuned with molecular specificity against a diverse array of particulates. Biological hydrogels (biogels) are essential in living systems to control the movement of cells and unwanted substances. However, current methods to control transport within biogels rely on altering the microstructure of the biogel matrix at a gross level, either by reducing the pore size to restrict passage through steric hindrance or by chemically modifying the matrix itself. Both methods are either nonspecific or not scalable. Here, we offer a new approach, based on weakly adhesive third-party molecular anchors, that allow for a variety of foreign entities to be trapped within a biogel simultaneously with exceptional potency and molecular specificity, without perturbing the bulk properties of the biogel. This strategy greatly increases our ability to control the properties of biogels at the nanoscale, including those used for wound healing or tissue engineering applications.}, journal={ACTA BIOMATERIALIA}, author={Schiller, Jennifer L. and Marvin, Allison and McCallen, Justin D. and Lai, Samuel K.}, year={2019}, month={Apr}, pages={95–103} }
 @article{chen_mckinley_wang_shi_mucha_forest_lai_2014, title={Transient Antibody-Mucin Interactions Produce a Dynamic Molecular Shield against Viral Invasion}, volume={106}, ISSN={["1542-0086"]}, DOI={10.1016/j.bpj.2014.02.038}, abstractNote={Given the difficulty in finding a cure for HIV/AIDS, a promising prevention strategy to reduce HIV transmission is to directly block infection at the portal of entry. The recent Thai RV144 trial offered the first evidence that an antibody-based vaccine may block heterosexual HIV transmission. Unfortunately, the underlying mechanism(s) for protection remain unclear. Here we theoretically examine a hypothesis that builds on our recent laboratory observation: virus-specific antibodies (Ab) can trap individual virions in cervicovaginal mucus (CVM), thereby reducing infection in vivo. Ab are known to have a weak-previously considered inconsequential-binding affinity with the mucin fibers that constitute CVM. However, multiple Ab can bind to the same virion at the same time, which markedly increases the overall Ab-mucin binding avidity, and creates an inheritable virion-mucin affinity. Our model takes into account biologically relevant length and timescales, while incorporating known HIV-Ab affinity and the respective diffusivities of viruses and Ab in semen and CVM. The model predicts that HIV-specific Ab in CVM leads to rapid formation and persistence of an HIV concentration front near the semen/CVM interface, far from the vaginal epithelium. Such an HIV concentration front minimizes the flux of HIV virions reaching target cells, and maximizes their elimination upon drainage of genital secretions. The robustness of the result implies that even exceedingly weak Ab-mucin affinity can markedly reduce the flux of virions reaching target cells. Beyond this specific application, the model developed here is adaptable to other pathogens, mucosal barriers, and geometries, as well as kinetic and diffusional effects, providing a tool for hypothesis testing and producing quantitative insights into the dynamics of immune-mediated protection.}, number={9}, journal={BIOPHYSICAL JOURNAL}, author={Chen, Alex and McKinley, Scott A. and Wang, Simi and Shi, Feng and Mucha, Peter J. and Forest, M. Gregory and Lai, Samuel K.}, year={2014}, month={May}, pages={2028–2036} }