scholarly journals Identification of a neutralizing epitope within minor repeat region of Plasmodium falciparum CS protein

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
J. Mauricio Calvo-Calle ◽  
Robert Mitchell ◽  
Rita Altszuler ◽  
Caroline Othoro ◽  
Elizabeth Nardin
Keyword(s):  
Monoclonal Antibodies ◽  
Neutralizing Antibodies ◽  
In Vivo Studies ◽  
Repeat Region ◽  
Fine Specificity ◽  
Humoral Immune ◽  
Major Surface ◽  
Murine Monoclonal Antibodies

AbstractMalaria remains a major cause of morbidity and mortality worldwide with 219 million infections and 435,000 deaths predominantly in Africa. The infective Plasmodium sporozoite is the target of a potent humoral immune response that can protect murine, simian and human hosts against challenge by malaria-infected mosquitoes. Early murine studies demonstrated that sporozoites or subunit vaccines based on the sporozoite major surface antigen, the circumsporozoite (CS) protein, elicit antibodies that primarily target the central repeat region of the CS protein. In the current murine studies, using monoclonal antibodies and polyclonal sera obtained following immunization with P. falciparum sporozoites or synthetic repeat peptides, we demonstrate differences in the ability of these antibodies to recognize the major and minor repeats contained in the central repeat region. The biological relevance of these differences in fine specificity was explored using a transgenic P. berghei rodent parasite expressing the P. falciparum CS repeat region. In these in vitro and in vivo studies, we demonstrate that the minor repeat region, comprised of three copies of alternating NANP and NVDP tetramer repeats, contains an epitope recognized by sporozoite-neutralizing antibodies. In contrast, murine monoclonal antibodies specific for the major CS repeats (NANP)n could be isolated from peptide-immunized mice that had limited or no sporozoite-neutralizing activity. These studies highlight the importance of assessing the fine specificity and functions of antirepeat antibodies elicited by P. falciparum CS-based vaccines and suggest that the design of immunogens to increase antibody responses to minor CS repeats may enhance vaccine efficacy.

scholarly journals Murine monoclonal antibodies against RBD of SARS-CoV-2 neutralize authentic wild type SARS-CoV-2 as well as B.1.1.7 and B.1.351 viruses and protect in vivo in a mouse model in a neutralization dependent manner

2021 ◽  
Author(s):  
Fatima Amanat ◽  
Shirin Strohmeier ◽  
Wen-Hsin Lee ◽  
Sandhya Bangaru ◽  
Andrew B Ward ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Severe Acute Respiratory Syndrome ◽  
Mouse Model ◽  
Neutralizing Antibodies ◽  
Dependent Manner ◽  
Receptor Binding Domain ◽  
Wild Type ◽  
Murine Monoclonal Antibodies

After first emerging in December 2019 in China, severe acute respiratory syndrome 2 (SARS-CoV-2) has since caused a pandemic leading to millions of infections and deaths worldwide. Vaccines have been developed and authorized but supply of these vaccines is currently limited. With new variants of the virus now emerging and spreading globally, it is essential to develop therapeutics that are broadly protective and bind conserved epitopes in the receptor binding domain (RBD) or the whole spike of SARS-CoV-2. In this study, we have generated mouse monoclonal antibodies (mAbs) against different epitopes on the RBD and assessed binding and neutralization against authentic SARS-CoV-2. We have demonstrated that antibodies with neutralizing activity, but not non-neutralizing antibodies, lower viral titers in the lungs when administered in a prophylactic setting in vivo in a mouse challenge model. In addition, most of the mAbs cross-neutralize the B.1.351 as well as the B.1.1.7 variants in vitro.

Murine monoclonal antibodies against murine uPA receptor produced in gene-deficient mice: Inhibitory effects on receptormediated uPA activity in vitro and in vivo

2007 ◽  
Vol 97 (06) ◽  
pp. 1013-1022 ◽  
Author(s):  
Jesper Pass ◽  
Annika Jögi ◽  
Ida Lund ◽  
Birgitte Rønø ◽  
Morten Rasch ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Lethal Dose ◽  
In Vivo Studies ◽  
Plasminogen Activation ◽  
Amino Terminal ◽  
Anthrax Toxins ◽  
Murine Monoclonal Antibodies ◽  
Deficient Mice

SummaryBinding of urokinase plasminogen activator (uPA) to its cellular receptor, uPAR, potentiates plasminogen activation and localizes it to the cell surface. Focal plasminogen activation is involved in both normal and pathological tissue remodeling processes including cancer invasion. The interaction between uPA and uPAR therefore represents a potential target for anti-invasive cancer therapy. Inhibitors of the human uPA-uPAR interaction have no effect in the murine system. To enable in-vivo studies in murine cancer models we have now generated murine monoclonal antibodies (mAbs) against murine uPAR (muPAR) by immunizing uPAR-deficient mice with recombinant muPAR and screened for antibodies, which inhibit the muPA-muPAR interaction. Two of the twelve mAbs obtained, mR1 and mR2, interfered with the interaction between muPAR and the amino-terminal fragment of muPA (mATF) when analyzed by surface plasmon resonance. The epitope for mR1 is located on domain I of muPAR, while that of mR2 is on domains (II-III). In cell binding experiments using radiolabelled mATF, the maximal inhibition obtained with mR1 was 85% while that obtained with mR2 was 50%. The IC50 value for mR1 was 0.67 nM compared to 0.14 nM for mATF. In an assay based on modified anthrax toxins, requiring cell-bound muPA activity for its cytotoxity, a ~50% rescue of the cells could be obtained by addition of mR1. Importantly, in-vivo efficacy of mR1 was demonstrated by the ability of mR1 to rescue mice treated with a lethal dose of uPA-activatable anthrax toxins.

scholarly journals In vitro immunization approach to generate specific murine monoclonal IgG antibodies

2020 ◽  
Author(s):  
Sophia Michelchen ◽  
Burkhard Micheel ◽  
Katja Hanack
Keyword(s):  
Monoclonal Antibodies ◽  
Legionella Pneumophila ◽  
B Lymphocyte ◽  
Laboratory Animals ◽  
Igg Antibody ◽  
Simplified Approach ◽  
Humoral Immune ◽  
Viral Coat

AbstractGenerating monoclonal antibodies to date is a time intense process requiring immunization of laboratory animals. The transfer of the humoral immune response into in vitro settings shortens this process and circumvents the necessity of animal immunization. However, orchestrating the complex interplay of immune cells in vitro is very challenging. We aimed for a simplified approach focusing on the protagonist of antibody production: the B lymphocyte. We activated purified murine B lymphocytes in vitro with combinations of antigen and stimuli. Within ten days of culture we induced specific IgM and IgG antibody responses against a viral coat protein. Permanently antibody-producing hybridomas were generated. Furthermore we used this method to induce a specific antibody response against Legionella pneumophila. We thus established an effective protocol to generate monoclonal antibodies in vitro. By overcoming the necessity of in vivo immunization it may be the first step towards a universal strategy to generate antibodies from various species.

scholarly journals Humanized Monoclonal Antibodies Derived from Chimpanzee Fabs Protect against Japanese Encephalitis Virus In Vitro and In Vivo

2008 ◽  
Vol 82 (14) ◽  
pp. 7009-7021 ◽  
Author(s):  
Ana P. Goncalvez ◽  
Cheng-Hsin Chien ◽  
Kamolchanok Tubthong ◽  
Inna Gorshkova ◽  
Carrie Roll ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Neutralizing Antibodies ◽  
Therapeutic Potential ◽  
Encephalitis Virus ◽  
Domain Iii ◽  
Humanized Monoclonal Antibodies

ABSTRACT Japanese encephalitis virus (JEV)-specific Fab antibodies were recovered by repertoire cloning from chimpanzees initially immunized with inactivated JE-VAX and then boosted with attenuated JEV SA14-14-2. From a panel of 11 Fabs recovered by different panning strategies, three highly potent neutralizing antibodies, termed Fabs A3, B2, and E3, which recognized spatially separated regions on the virion, were identified. These antibodies reacted with epitopes in different domains: the major determinant for Fab A3 was Lys179 (domain I), that for Fab B2 was Ile126 (domain II), and that for Fab E3 was Gly302 (domain III) in the envelope protein, suggesting that these antibodies neutralize the virus by different mechanisms. Potent neutralizing antibodies reacted with a low number of binding sites available on the virion. These three Fabs and derived humanized monoclonal antibodies (MAbs) exhibited high neutralizing activities against a broad spectrum of JEV genotype strains. Demonstration of antibody-mediated protection of JEV infection in vivo is provided using the mouse encephalitis model. MAb B2 was most potent, with a 50% protective dose (ED50) of 0.84 μg, followed by MAb A3 (ED50 of 5.8 μg) and then MAb E3 (ED50 of 24.7 μg) for a 4-week-old mouse. Administration of 200 μg/mouse of MAb B2 1 day after otherwise lethal JEV infection protected 50% of mice and significantly prolonged the average survival time compared to that of mice in the unprotected group, suggesting a therapeutic potential for use of MAb B2 in humans.

scholarly journals In vitro and in vivo preclinical studies predict REGEN-COV protection against emergence of viral escape in humans

2021 ◽  
Author(s):  
Richard Copin ◽  
Alina Baum ◽  
Elzbieta Wloga ◽  
Kristen E. Pascal ◽  
Stephanie Giordano ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Therapeutic Option ◽  
Viral Escape ◽  
Spike Protein ◽  
In Vivo Studies ◽  
Preclinical Studies ◽  
Global Pandemic ◽  
Emerging Virus

SummaryMonoclonal antibodies against SARS-CoV-2 are a clinically validated therapeutic option against COVID-19. As rapidly emerging virus mutants are becoming the next major concern in the fight against the global pandemic, it is imperative that these therapeutic treatments provide coverage against circulating variants and do not contribute to development of treatment emergent resistance. To this end, we investigated the sequence diversity of the spike protein and monitored emergence of minor virus variants in SARS-COV-2 isolates found in nature or identified from preclinical in vitro and in vivo studies and in the clinic. This study demonstrates that a combination of noncompeting antibodies not only provides full coverage against currently circulating variants but also protects against emergence of new such variants and their potential seeding into the population in a clinical setting.

scholarly journals The P. falciparum CSP repeat region contains three distinct epitopes required for protection by antibodies in vivo

2021 ◽  
Vol 17 (11) ◽  
pp. e1010042
Author(s):  
Yevel Flores-Garcia ◽  
Lawrence T. Wang ◽  
Minah Park ◽  
Beejan Asady ◽  
Azza H. Idris ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Monoclonal Antibodies ◽  
Malaria Infection ◽  
Vaccine Development ◽  
Circumsporozoite Protein ◽  
Repeat Region ◽  
Human Mabs ◽  
Necessary And Sufficient

Rare and potent monoclonal antibodies (mAbs) against the Plasmodium falciparum (Pf) circumsporozoite protein (CSP) on infective sporozoites (SPZ) preferentially bind the PfCSP junctional tetrapeptide NPDP or NVDP minor repeats while cross-reacting with NANP major repeats in vitro. The extent to which each of these epitopes is required for protection in vivo is unknown. Here, we assessed whether junction-, minor repeat- and major repeat-preferring human mAbs (CIS43, L9 and 317 respectively) bound and protected against in vivo challenge with transgenic P. berghei (Pb) SPZ expressing either PfCSP with the junction and minor repeats knocked out (KO), or PbCSP with the junction and minor repeats knocked in (KI). In vivo protection studies showed that the junction and minor repeats are necessary and sufficient for CIS43 and L9 to neutralize KO and KI SPZ, respectively. In contrast, 317 required major repeats for in vivo protection. These data establish that human mAbs can prevent malaria infection by targeting three different protective epitopes (NPDP, NVDP, NANP) in the PfCSP repeat region. This report will inform vaccine development and the use of mAbs to passively prevent malaria.

Preparation of human and murine monoclonal antibodies: antigens combined with or conjugated to lipopeptides constitute potent immunogens for in vitro and in vivo immunizations

1990 ◽  
Vol 1 (3) ◽  
pp. 137-144 ◽  
Author(s):  
Petra Hoffmann ◽  
Manuel Jimenez-Diaz ◽  
Manuel Loleit ◽  
Wilfried Tröger ◽  
Karl-Heinz Wiesmüller ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Murine Monoclonal Antibodies

scholarly journals Molecular mechanisms linking wound inflammation and fibrosis: knockdown of osteopontin leads to rapid repair and reduced scarring

2008 ◽  
Vol 205 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Ryoichi Mori ◽  
Tanya J. Shaw ◽  
Paul Martin
Keyword(s):  
Mast Cell ◽  
Neutralizing Antibodies ◽  
Molecular Mechanisms ◽  
Mouse Skin ◽  
Inflammatory Cells ◽  
In Vivo Studies ◽  
Paracrine Factors ◽  
Cultured Fibroblasts

Previous studies of tissue repair have revealed osteopontin (OPN) to be up-regulated in association with the wound inflammatory response. We hypothesize that OPN may contribute to inflammation-associated fibrosis. In a series of in vitro and in vivo studies, we analyze the effects of blocking OPN expression at the wound, and determine which inflammatory cells, and which paracrine factors from these cells, may be responsible for triggering OPN expression in wound fibroblasts. Delivery of OPN antisense oligodeoxynucleotides into mouse skin wounds by release from Pluronic gel decreases OPN protein levels at the wound and results in accelerated healing and reduced granulation tissue formation and scarring. To identify which leukocytic lineages may be responsible for OPN expression, we cultured fibroblasts in macrophage-, neutrophil-, or mast cell–conditioned media (CM), and found that macrophage- and mast cell–secreted factors, specifically platelet-derived growth factor (PDGF), induced fibroblast OPN expression. Correspondingly, Gleevec, which blocks PDGF receptor signaling, and PDGF-Rβ–neutralizing antibodies, inhibited OPN induction by macrophage-CM. These studies indicate that inflammation-triggered expression of OPN both hinders the rate of repair and contributes to wound fibrosis. Thus, OPN and PDGF are potential targets for therapeutic modulation of skin repair to improve healing rate and quality.

scholarly journals A bifluorescent-based assay for the identification of neutralizing antibodies against SARS-CoV-2 variants of concern in vitro and in vivo

2021 ◽  
Author(s):  
Kevin Chiem ◽  
Desarey Morales Vasquez ◽  
Jesus A. Silvas ◽  
Jun-Gyu Park ◽  
Michael S. Piepenbrink ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Vaccine Efficacy ◽  
Neutralizing Antibodies ◽  
Viral Infections ◽  
Rapid Assessment ◽  
The United States ◽  
Viral Fitness ◽  
Human Monoclonal Antibodies

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged at the end of 2019 and has been responsible for the still ongoing coronavirus disease 2019 (COVID-19) pandemic. Prophylactic vaccines have been authorized by the United States (US) Food and Drug Administration (FDA) for the prevention of COVID-19. Identification of SARS-CoV-2 neutralizing antibodies (NAbs) is important to assess vaccine protection efficacy, including their ability to protect against emerging SARS-CoV-2 variants of concern (VoC). Here we report the generation and use of a recombinant (r)SARS-CoV-2 USA/WA1/2020 (WA-1) strain expressing Venus and a rSARS-CoV-2 expressing mCherry and containing mutations K417N, E484K, and N501Y found in the receptor binding domain (RBD) of the spike (S) glycoprotein of the South African (SA) B.1.351 (beta, β) VoC, in bifluorescent-based assays to rapidly and accurately identify human monoclonal antibodies (hMAbs) able to neutralize both viral infections in vitro and in vivo. Importantly, our bifluorescent-based system accurately recapitulated findings observed using individual viruses. Moreover, fluorescent-expressing rSARS-CoV-2 and the parental wild-type (WT) rSARS-CoV-2 WA-1 had similar viral fitness in vitro , as well as similar virulence and pathogenicity in vivo in the K18 human angiotensin converting enzyme 2 (hACE2) transgenic mouse model of SARS-CoV-2 infection. We demonstrate that these new fluorescent-expressing rSARS-CoV-2 can be used in vitro and in vivo to easily identify hMAbs that simultaneously neutralize different SARS-CoV-2 strains, including VoC, for the rapid assessment of vaccine efficacy or the identification of prophylactic and/or therapeutic broadly NAbs for the treatment of SARS-CoV-2 infection. IMPORTANCE SARS-CoV-2 is responsible of the COVID-19 pandemic that has warped daily routines and socioeconomics. There is still an urgent need for prophylactics and therapeutics to treat SARS-CoV-2 infections. In this study, we demonstrate the feasibility of using bifluorescent-based assays for the rapid identification of human monoclonal antibodies (hMAbs) with neutralizing activity against SARS-CoV-2, including variants of concern (VoC) in vitro and in vivo. Importantly, results obtained with these bifluorescent-based assays recapitulate those observed with individual viruses demonstrating their feasibility to rapidly advance our understanding of vaccine efficacy and to identify broadly protective human NAbs for the therapeutic treatment of SARS-CoV-2.

Comparison of Paraquat-Specific Murine Monoclonal Antibodies Produce by in Vitro and in Vivo Immunization

1988 ◽  
Vol 11 (1) ◽  
pp. 261-267
Author(s):  
SHANE C. JOHNSTON ◽  
MARK BOWLES ◽  
DONALD J. WINZOR ◽  
SUSAN M. POND
Keyword(s):  
Monoclonal Antibodies ◽  
Murine Monoclonal Antibodies
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