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 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.

Characterization of Cell-Associated Plasminogen Activation Catalyzed by Urokinase-Type Plasminogen Activator, but Independent of Urokinase Receptor (uPAR, CD87)

Blood ◽  
1999 ◽  
Vol 93 (11) ◽  
pp. 3839-3846 ◽  
Author(s):  
Colin Longstaff ◽  
R. Elizabeth Merton ◽  
Pere Fabregas ◽  
Jordi Felez
Keyword(s):  
Molecular Weight ◽  
Leukemic Cell ◽  
Plasminogen Activation ◽  
Single Chain ◽  
Amino Terminal ◽  
Leukemic Cell Lines ◽  
Upa Receptor ◽  
Type Plasminogen Activator

Abstract The 55-kD urokinase (uPA) receptor (uPAR, CD87) is capable of binding uPA and may be involved in regulating cell-associated plasminogen activation and pericellular proteolysis. While investigating the relationship between uPAR levels and plasmin generation, we found that uPA-catalyzed plasminogen activation is stimulated by cells which do not express uPAR. This uPAR-independent mechanism appears to be at least as effective in vitro as uPAR-dependent stimulation, such that stimulation on the order of 30-fold was observed, resulting from improvements in both apparent kcat and apparent Km. The mechanism depends on simultaneous binding of both uPA and plasminogen to the cell and requires the presence of the amino-terminal fragment (ATF), available in single chain and two chain high-molecular-weight uPA, but not low-molecular-weight uPA. Stimulation was observed in all leukemic cell lines investigated at similar optimum concentrations of 106to 107 cells/mL and may be more general. A mechanism is proposed whereby uPA can associate with binding sites on the cell surface of lower affinity, but higher capacity than uPAR, but these are sufficient to stimulate plasmin generation even at subphysiologic uPA concentrations. This mechanism is likely to operate under conditions commonly used for in vitro studies and may have some significance in vivo.

scholarly journals A Neutralizing Prolactin Receptor Antibody Whose In Vivo Application Mimics the Phenotype of Female Prolactin Receptor-Deficient Mice

Endocrinology ◽  
2015 ◽  
Vol 156 (11) ◽  
pp. 4365-4373 ◽  
Author(s):  
Christiane Otto ◽  
Anna Särnefält ◽  
Anne Ljungars ◽  
Siegmund Wolf ◽  
Beate Rohde-Schulz ◽  
...  
Keyword(s):  
Prolactin Receptor ◽  
Human Monoclonal Antibody ◽  
Negative Control ◽  
In Vivo Studies ◽  
Dependent Manner ◽  
Female Mice ◽  
Prolactin Synthesis ◽  
Deficient Mice

The prolactin receptor (PRLR) has been implicated in a variety of physiological processes (lactation, reproduction) and diseases (breast cancer, autoimmune diseases). Prolactin synthesis in the pituitary and extrapituitary sites is regulated by different promoters. Dopamine receptor agonists such as bromocriptine can only interfere with pituitary prolactin synthesis and thus do not induce a complete blockade of PRLR signaling. Here we describe the identification of a human monoclonal antibody 005-C04 that blocks PRLR-mediated signaling at nanomolar concentrations in vitro. In contrast to a negative control antibody, the neutralizing PRLR antibody 005-C04 inhibits signal transducer and activator of transcription 5 phosphorylation in T47D cells and proliferation of BaF3 cells stably expressing murine or human PRLRs in a dose-dependent manner. In vivo application of this new function-blocking PRLR antibody reflects the phenotype of PRLR-deficient mice. After antibody administration female mice become infertile in a reversible manner. In lactating dams, the antibody induces mammary gland involution and negatively interferes with lactation capacity as evidenced by reduced milk protein expression in mammary glands and impaired litter weight gain. Antibody-mediated blockade of the PRLR in vivo stimulates hair regrowth in female mice. Compared with peptide-derived PRLR antagonists, the PRLR antibody 005-C04 exhibits several advantages such as higher potency, noncompetitive inhibition of PRLR signaling, and a longer half-life, which allows its use as a tool compound also in long-term in vivo studies. Therefore, we suggest that this antibody will help to further our understanding of the role of auto- and paracrine PRLR signaling in health and disease.

Species differences in the reactivation of organophosphate-inhibited plasma esterases by diacetymonoxime

1976 ◽  
Vol 54 (2) ◽  
pp. 86-92 ◽  
Author(s):  
D. J. Ecobichon
Keyword(s):  
Guinea Pig ◽  
Species Differences ◽  
Marked Effect ◽  
Lethal Dose ◽  
Rat Plasma ◽  
In Vivo Studies ◽  
Rapid Rate ◽  
Plasma Enzymes

A study was conducted to assess whether the protection afforded to organophosphate-poisoned animals by diacetylmonoxime (DAM) was correlated with the reactivation of non-essential aliesterases (AliE). In vitro, the DAM-catalyzed reactivation of plasma AliE and cholinesterases (ΨChE) of rat, rabbit and guinea pig inhibited by 10−5 M diisopropylphosphorofluoridate (DFP) and O,O-dimethyl-2,2-dichlorovinyl phosphate (DDVP) was investigated. Marked reactivation of the rat plasma enzymes was achieved with 10 mM DAM. Higher concentrations (30 mM) were necessary for the slow reactivation of rabbit and guinea pig plasma AliE. Reactivation of the ΨChE of these species was comparatively slow. Reactivation of DDVP-inhibited esterases proceeded in all species at a more rapid rate than those inhibited by DFP. The dependence of ΨChE reactivation upon concomitant more rapid reactivation of AliE by DAM was demonstrated using Sephadex fractionated AliE and ΨChE but only a marked effect was observed with the rat, suggesting that the plasma AliE of this species is functionally different.The in vitro observations were confirmed by in vivo studies in rats and rabbits. DAM (50 or 150 mg/kg), administered to atropinized rats 15 min before a lethal dose of DFP, protected the animals. Few severe toxic signs were observed and reactivation of both plasma AliE and ΨChE occurred. In contrast, DAM protected the rabbit against a lethal dose of DFP but only reactivation of the erythrocyte acetylcholinesterase was observed.

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.

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

Structure, function and biology of tissue factor pathway inhibitor-2

2005 ◽  
Vol 94 (12) ◽  
pp. 1122-1130 ◽  
Author(s):  
Hitendra S. Chand ◽  
Donald C. Foster ◽  
Walter Kisiel
Keyword(s):  
Tissue Factor ◽  
Tissue Factor Pathway Inhibitor ◽  
Serine Proteinase ◽  
In Vivo Studies ◽  
Amino Terminal ◽  
Tissue Factor Pathway ◽  
Kunitz Type ◽  
Carboxy Terminal

SummaryTissue factor pathway inhibitor-2 (TFPI-2) is a 32 kDa matrix-associated Kunitz-type serine proteinase inhibitor consisting of a short amino-terminal region, three tandem Kunitz-type domains and a positively charged carboxy-terminal tail. Human TFPI-2, previously designated as placental protein 5, inhibits a broad spectrum of serine proteinases almost exclusively through its first Kunitz-type domain, and is thought to play an important role in the regulation of extracellular matrix digestion and re-modeling. In this context, reduced synthesis of TFPI-2 has been related to numerous pathophysiological processes such as inflammation, angiogenesis, atherosclerosis, retinal degeneration and tumor growth/metastasis. In this review, we document current information regarding the expression of TFPI-2 by various tissues, its inhibitory activity and proteinase specificity in-vitro, and discuss possible physiological roles for this inhibitor based on in-vivo studies.

Characterization of Cell-Associated Plasminogen Activation Catalyzed by Urokinase-Type Plasminogen Activator, but Independent of Urokinase Receptor (uPAR, CD87)

Blood ◽  
1999 ◽  
Vol 93 (11) ◽  
pp. 3839-3846 ◽  
Author(s):  
Colin Longstaff ◽  
R. Elizabeth Merton ◽  
Pere Fabregas ◽  
Jordi Felez
Keyword(s):  
Molecular Weight ◽  
Leukemic Cell ◽  
Plasminogen Activation ◽  
Single Chain ◽  
Amino Terminal ◽  
Leukemic Cell Lines ◽  
Upa Receptor ◽  
Type Plasminogen Activator

The 55-kD urokinase (uPA) receptor (uPAR, CD87) is capable of binding uPA and may be involved in regulating cell-associated plasminogen activation and pericellular proteolysis. While investigating the relationship between uPAR levels and plasmin generation, we found that uPA-catalyzed plasminogen activation is stimulated by cells which do not express uPAR. This uPAR-independent mechanism appears to be at least as effective in vitro as uPAR-dependent stimulation, such that stimulation on the order of 30-fold was observed, resulting from improvements in both apparent kcat and apparent Km. The mechanism depends on simultaneous binding of both uPA and plasminogen to the cell and requires the presence of the amino-terminal fragment (ATF), available in single chain and two chain high-molecular-weight uPA, but not low-molecular-weight uPA. Stimulation was observed in all leukemic cell lines investigated at similar optimum concentrations of 106to 107 cells/mL and may be more general. A mechanism is proposed whereby uPA can associate with binding sites on the cell surface of lower affinity, but higher capacity than uPAR, but these are sufficient to stimulate plasmin generation even at subphysiologic uPA concentrations. This mechanism is likely to operate under conditions commonly used for in vitro studies and may have some significance in vivo.

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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