Production of Monoclonal Antibodies in a Mouse Model via Lipopolysaccharide Conjugates with Synthetic Polymers Specific toSalmonellaEnteritidis O Antigen

2010 ◽  
Vol 7 (12) ◽  
pp. 1521-1529 ◽  
Author(s):  
Ayse Nalbantsoy ◽  
Ismail Karaboz ◽  
Ismet Deliloglu Gurhan
Keyword(s):  
Monoclonal Antibodies ◽  
Mouse Model ◽  
Synthetic Polymers ◽  
O Antigen

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.

scholarly journals Impact of Immunoglobulin Isotype and Epitope on the Functional Properties of Vibrio cholerae O-Specific Polysaccharide-Specific Monoclonal Antibodies

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Robert C. Kauffman ◽  
Oluwaseyi Adekunle ◽  
Hanyi Yu ◽  
Alice Cho ◽  
Lindsay E. Nyhoff ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Functional Properties ◽  
Diarrheal Disease ◽  
Cross Linking ◽  
Specific Antibodies ◽  
Immunoglobulin Isotype ◽  
High Affinity ◽  
O Antigen ◽  
The Impact ◽  
Motility Inhibition

ABSTRACT Vibrio cholerae causes the severe diarrheal disease cholera. Clinical disease and current oral cholera vaccines generate antibody responses associated with protection. Immunity is thought to be largely mediated by lipopolysaccharide (LPS)-specific antibodies, primarily targeting the O-antigen. However, the properties and protective mechanism of functionally relevant antibodies have not been well defined. We previously reported on the early B cell response to cholera in a cohort of Bangladeshi patients, from which we characterized a panel of human monoclonal antibodies (MAbs) isolated from acutely induced plasmablasts. All antibodies in that previous study were expressed in an IgG1 backbone irrespective of their original isotype. To clearly determine the impact of affinity, immunoglobulin isotype and subclass on the functional properties of these MAbs, we re-engineered a subset of low- and high-affinity antibodies in different isotype and subclass immunoglobulin backbones and characterized the impact of these changes on binding, vibriocidal, agglutination, and motility inhibition activity. While the high-affinity antibodies bound similarly to O-antigen, irrespective of isotype, the low-affinity antibodies displayed significant avidity differences. Interestingly, despite exhibiting lower binding properties, variants derived from the low-affinity MAbs had comparable agglutination and motility inhibition properties to the potently binding antibodies, suggesting that how the MAb binds to the O-antigen may be critical to function. In addition, not only pentameric IgM and dimeric IgA, but also monomeric IgA, was remarkably more potent than their IgG counterparts at inhibiting motility. Finally, analyzing highly purified F(ab) versions of these antibodies, we show that LPS cross-linking is essential for motility inhibition. IMPORTANCE Immunity to the severe diarrheal disease cholera is largely mediated by lipopolysaccharide (LPS)-specific antibodies. However, the properties and protective mechanisms of functionally relevant antibodies have not been well defined. Here, we have engineered low and high-affinity LPS-specific antibodies in different immunoglobulin backbones in order to assess the impact of affinity, immunoglobulin isotype, and subclass on binding, vibriocidal, agglutination, and motility inhibition functional properties. Importantly, we found that affinity did not directly dictate functional potency since variants derived from the low-affinity MAbs had comparable agglutination and motility inhibition properties to the potently binding antibodies. This suggests that how the antibody binds sterically may be critical to function. In addition, not only pentameric IgM and dimeric IgA, but also monomeric IgA, was remarkably more potent than their IgG counterparts at inhibiting motility. Finally, analyzing highly purified F(ab) versions of these antibodies, we show that LPS cross-linking is essential for motility inhibition.

scholarly journals Role of the wbt Locus of Francisella tularensis in Lipopolysaccharide O-Antigen Biogenesis and Pathogenicity

2006 ◽  
Vol 75 (1) ◽  
pp. 536-541 ◽  
Author(s):  
Catherine Raynaud ◽  
Karin L. Meibom ◽  
Marie-Annick Lety ◽  
Iharilalao Dubail ◽  
Thomas Candela ◽  
...  
Keyword(s):  
Mouse Model ◽  
Gene Cluster ◽  
Francisella Tularensis ◽  
Bacterial Pathogen ◽  
Complete Loss ◽  
Intracellular Replication ◽  
O Antigen ◽  
Transposon Insertion ◽  
Insertion Mutants

ABSTRACT Francisella tularensis is a highly infectious bacterial pathogen, responsible for the zoonotic disease tularemia. We screened a bank of transposon insertion mutants of F. tularensis subsp. holarctica LVS for colony morphology alterations and selected a mutant with a transposon insertion in wbtA, the first gene of the predicted lipopolysaccharide O-antigen gene cluster. Inactivation of wbtA led to the complete loss of O antigen, conferred serum sensitivity, impaired intracellular replication, and severely attenuated virulence in the mouse model. Notably, this mutant afforded protection against a challenge against virulent LVS.

scholarly journals Isotype Switching Increases Efficacy of Antibody Protection against Cryptococcus neoformans Infection in Mice

1998 ◽  
Vol 66 (3) ◽  
pp. 1057-1062 ◽  
Author(s):  
Rui Rong Yuan ◽  
Gadi Spira ◽  
Jin Oh ◽  
Melia Paizi ◽  
Arturo Casadevall ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Mouse Model ◽  
Antibody Response ◽  
Cryptococcus Neoformans ◽  
Immunoglobulin G ◽  
Relative Efficacy ◽  
Isotype Switching ◽  
Mediate Immunity ◽  
Igg Isotypes ◽  
The Relationship

ABSTRACT The isotype and epitope specificities of antibodies both contribute to the efficacy of antibodies that mediate immunity toCryptococcus neoformans, but the relationship between these properties is only partially understood. In this study, we analyzed the efficacy of protection of two sets of immunoglobulin G (IgG) isotype switch variants from two IgG3 monoclonal antibodies (MAbs) which are either not protective or disease enhancing, depending on the mouse model used. The two IgG3 MAbs 3E5 and 4H3 have different epitope specificities. Protection experiments were done with A/JCr mice infected intravenously with C. neoformans and administered with 3E5 IgG3 and its IgG1, IgG2a, and IgG2b switch variants. These experiments revealed that IgG1, IgG2b, and IgG2a were each more effective than IgG3. For 4H3 IgG3 and its IgG1 and IgG2b switch variants, the relative efficacy was IgG2b > IgG1 >> IgG3. The combination of 3E5 IgG3 and 4H3 IgG3 was more deleterious than either IgG3 alone. All IgG isotypes were opsonic for mouse bronchoalveolar cells, with the relative efficacy being IgG2b > IgG2a > IgG1 > IgG3. These results (i) confirm that a nonprotective IgG3 MAb can be converted to a protective MAb by isotype switching, (ii) indicate that the efficacy of protection of an IgG1 MAb can be increased by isotype switching to another subclass, (iii) show that protective and nonprotective IgG MAbs are opsonic, and (iv) provide additional evidence for the concept that the efficacy of the antibody response to C. neoformans is dependent on the type of MAb elicited.

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