Contribution of murine IgG Fc regions to antibody binding to the capsule of<i>Burkholderia pseudomallei</i>

Dillon, Michael J.; Loban, Rachael A.; Reed, Dana E.; Thorkildson, Peter; Pflughoeft, Kathryn J.; Pandit, Sujata G.; Brett, Paul J.; Burtnick, Mary N.; AuCoin, David P.

doi:10.1080/21505594.2016.1176655

Cited by 12 publications

(15 citation statements)

References 55 publications

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“…Increased binding of hJF5 and hJF5-NODAGA compared to mJF5 and mJF5-NODAGA, although not significant, was further demonstrated in vitro during ELISA tests with the purified mannoprotein antigen. The reasons for this increased affinity have yet to be established, but there is increasing evidence to suggest that exchanging murine and human immunoglobulin constant chains can have profound effects on the kinetics of antigen binding 28 , 29 . Furthermore, while there is extensive anecdotal and unpublished evidence that attempts to generate humanised mAbs based on mouse V regions have failed to produce useful antibodies because of loss of affinity and specificity, our work shows successful generation of a higher affinity (humanised) antibody for in vivo imaging of IPA, and retention of specificity for the invasive hyphal growth phase of the pathogen.…”

Section: Discussionmentioning

confidence: 99%

Towards Translational ImmunoPET/MR Imaging of Invasive Pulmonary Aspergillosis: The Humanised Monoclonal Antibody JF5 Detects Aspergillus Lung Infections In Vivo

Davies¹,

Rolle²,

Maurer³

et al. 2017

Theranostics

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Invasive pulmonary aspergillosis (IPA) is a life-threatening lung disease of hematological malignancy or bone marrow transplant patients caused by the ubiquitous environmental fungus Aspergillus fumigatus. Current diagnostic tests for the disease lack sensitivity as well as specificity, and culture of the fungus from invasive lung biopsy, considered the gold standard for IPA detection, is slow and often not possible in critically ill patients. In a previous study, we reported the development of a novel non-invasive procedure for IPA diagnosis based on antibody-guided positron emission tomography and magnetic resonance imaging (immunoPET/MRI) using a [64Cu]DOTA-labeled mouse monoclonal antibody (mAb), mJF5, specific to Aspergillus. To enable translation of the tracer to the clinical setting, we report here the development of a humanised version of the antibody (hJF5), and pre-clinical imaging of lung infection using a [64Cu]NODAGA-hJF5 tracer. The humanised antibody tracer shows a significant increase in in vivo biodistribution in A. fumigatus infected lungs compared to its radiolabeled murine counterpart [64Cu]NODAGA-mJF5. Using reverse genetics of the pathogen, we show that the antibody binds to the antigenic determinant β1,5-galactofuranose (Galf) present in a diagnostic mannoprotein antigen released by the pathogen during invasive growth in the lung. The absence of the epitope Galf in mammalian carbohydrates, coupled with the enhanced imaging capabilities of the hJF5 antibody, means that the [64Cu]NODAGA-hJF5 tracer developed here represents an ideal candidate for the diagnosis of IPA and translation to the clinical setting.

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Section: Discussionmentioning

confidence: 99%

Towards Translational ImmunoPET/MR Imaging of Invasive Pulmonary Aspergillosis: The Humanised Monoclonal Antibody JF5 Detects Aspergillus Lung Infections In Vivo

Davies¹,

Rolle²,

Maurer³

et al. 2017

Theranostics

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“…In this issue of Virulence , Dillon et al. 23 demonstrate that class switching has a profound impact on IgG3 antibodies against the CPS of the globally distributed emerging human pathogen Burkholderia pseudomallei . 24-26 Interestingly, the CPS under investigation is an unusual polysaccharide, consisting of a linear homopolymer of a 2- O -acetyl-6-deoxy-heptopyranose.…”

mentioning

confidence: 99%

Isotype switching: Mouse IgG3 constant region drives increased affinity for polysaccharide antigens

Harmer

Chahwan

2016

Virulence

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“…Though the pharmaceutical industry has focused primarily on development of hIgG 1 antibodies, there are increasing efforts to compare the efficacy of different antibody isotypes and subclasses in treating both cancer and infectious disease (31)(32)(33). Despite mIgG 2a and mIgG 2b being most similar to hIgG 1 , direct comparisons between mIgG 1 and mIgG 3 exclusively have provided important insights into antibody-mediated resolution of infection (12,34,35). Studies investigating anti-capsular antibodies against Cryptococcus neoformans, for example, have suggested that mIgG 3 is poorly suited to protect against infection compared with mIgG 1 (36,37), whereas protection in mice from Bacillus anthracis spores was exclusively mediated by mIgG 3 (8).…”

Section: Discussionmentioning

confidence: 99%

“…This suggests that mIgG 3 has some evolutionary importance in protecting against encapsulated organisms. (35,41). This difference may be due to greater contribution of the mIgG 3 hinge region or disulfide bonds to K. pneumoniae CPS epitopes (42), and further digestion of the antibody into Fab fragments or replacement of heavy chain domains may shed more light on these interactions (8).…”

Section: Discussionmentioning

confidence: 99%

The Role of IgG Subclass in Antibody-Mediated Protection against Carbapenem-ResistantKlebsiella pneumoniae

Motley

Diago-Navarro

Banerjee

et al. 2020

Preprint

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Monoclonal antibodies (Abs) have the potential to assist in the battle against multidrug-resistant bacteria such as Carbapenem-Resistant Klebsiella pneumoniae (CR-Kp). However, the characteristics by which these Abs function, such as the role of antibody subclass, must be determined before such modalities can be carried from the bench to the bedside. We performed a subclass switch on anti-capsular monoclonal murine IgG3 (mIgG3) hybridomas and identified and purified a murine IgG1 (mIgG1) hybridoma line through sib selection. We then compared the ability of the mIgG1 and mIgG3 antibodies to control CR-Kp ST258 infection both in vitro and in vivo. We found by ELISA and flow cytometry that mIgG3 has superior binding to CR-Kp CPS and superior agglutinating ability compared to mIgG1. The mIgG3 also predictably had better complement-mediated serum bactericidal activity than the mIgG1 and also promoted neutrophil-mediated killing at concentrations lower than the mIgG1. In contrast, the mIgG1 had marginally better activity in improving macrophage-mediated phagocytosis. Comparing their activities in a pulmonary infection model with wild type as well as neutropenic mice, both antibodies reduced organ burden in a non-lethal challenge, regardless of neutrophil status, with mIgG1 having the highest overall burden reduction in both scenarios. However, at a lethal inoculum, both antibodies showed reduced efficacy in neutropenic mice, with mIgG3 retaining the most activity. These findings suggest the viability of monoclonal Ab adjunctive therapy in neutropenic patients that cannot mount their own immune response, while also providing some insight into the relative contributions of immune mediators in CR-Kp protection.ImportanceCarbapenem-resistant Klebsiella pneumoniae is an urgent public health threat that causes life-threatening infections in immunocompromised hosts. Its resistance to nearly all antibiotics necessitates novel strategies to treat it, including the use of monoclonal antibodies. Monoclonal antibodies are emerging as important adjuncts to traditional pharmaceuticals, and studying how they protect against specific bacteria such as Klebsiella pneumoniae is crucial to their development as effective therapies. Antibody subclass is often overlooked but is a major factor in how an antibody interacts with other mediators of immunity. This paper is the first to examine how the subclass of anti-capsular monoclonal antibodies can affect efficacy against CR-Kp. Additionally, this work sheds light on the viability of monoclonal antibody therapy in neutropenic patients, who are most vulnerable to CR-Kp infection.

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Contribution of murine IgG Fc regions to antibody binding to the capsule ofBurkholderia pseudomallei

Cited by 12 publications

References 55 publications

Towards Translational ImmunoPET/MR Imaging of Invasive Pulmonary Aspergillosis: The Humanised Monoclonal Antibody JF5 Detects Aspergillus Lung Infections In Vivo

Towards Translational ImmunoPET/MR Imaging of Invasive Pulmonary Aspergillosis: The Humanised Monoclonal Antibody JF5 Detects Aspergillus Lung Infections In Vivo

Isotype switching: Mouse IgG3 constant region drives increased affinity for polysaccharide antigens

The Role of IgG Subclass in Antibody-Mediated Protection against Carbapenem-ResistantKlebsiella pneumoniae

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