Binding affinities of human IgG1 and chimerized pig and rabbit derivatives to human, pig and rabbit Fc gamma receptor IIIA

Bhatti, Maryam M.; Cai, Allen G.; Theunissen, Jan-Willem

doi:10.1371/journal.pone.0219999

Cited by 4 publications

(3 citation statements)

References 37 publications

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“…The chimeric pig HM79-16 antibody (HM79-pig-IgG), however, does not show any ADCC activities by human, monkey or ferret FcγRIIIA and mouse FcγRIV, except for pig FcγRIIIA itself where the AF pig IgG outperforms the WT counterpart (not shown). This is in line with the report that pig IgG only binds to its own FcγRIIIA but not to human or rabbit FcγRIIIA [ 38 ].…”

Section: Methodssupporting

confidence: 92%

Cross-species higher sensitivities of FcγRIIIA/FcγRIV to afucosylated IgG for enhanced ADCC

Mao

Near

Zhong

et al. 2021

Antibody Therapeutics

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Background Expressing afucosylated human IgG1 antibodies with Chinese hamster ovary (CHO) cells deficient of α-(1,6)-fucosyltransferase (FUT8) is being more and more accepted as a routine method to enhance antibody-dependent cellular cytotoxicity (ADCC) of therapeutic antibodies, especially for anti-cancer regimens. However, in pre-clinical studies relying on disease models other than mice and primates, e.g., those underrepresented species for infectious diseases, it is less clear whether such afucosylated antibodies can demonstrate enhanced therapeutic index. This is because the orthologues of human FcγRIIIA or mouse FcγRIV from those species have not been well characterized. Methods We set up a luciferase-based ADCC assay with Jurkat reporter cells expressing FcγRIIIA/FcγRIV from human, mouse, rat, hamster, guinea pig, ferret, rabbit, cat, dog, pig and monkey, and also produced human, mouse, hamster, rabbit and pig IgG from wild type and Fut8−/− CHO cells or hybridomas. Results We confirmed that enhanced stimulation through FcγRIIIA/FcγRIV by afucosylated IgG, as compared with wild type IgG, is a cross-species phenomenon. Conclusions Thus, efficacy and toxicology studies of the next generation afucosylated therapeutic IgG and Fc fusion proteins in these underrepresented animal models should be expected to generate translatable data for treating human diseases, leading to the expanded applications of this new class of glycoengineered biologics.

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Section: Methodssupporting

confidence: 92%

Cross-species higher sensitivities of FcγRIIIA/FcγRIV to afucosylated IgG for enhanced ADCC

Mao

Near

Zhong

et al. 2021

Antibody Therapeutics

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“…To validate the specificity of the monoclonal anti-GLP-1R antibody in these brain regions, a rabbitized version of the antibody was generated using recombinant technology, whereby the heavy and light chain variable regions from the mouse monoclonal anti-GLP-1R antibody were grafted onto a rabbit IgG to generate a rabbit monoclonal version of clone 7F38A2 (detailed in Supplemental Fig. 1 and as described earlier (Bhatti et al 2019 )).…”

Section: Methodsmentioning

confidence: 99%

Distribution and ultrastructural localization of the glucagon-like peptide-1 receptor (GLP-1R) in the rat brain

et al. 2020

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Glucagon-like peptide-1 (GLP-1) inhibits food intake and regulates glucose homeostasis. These actions are at least partly mediated by central GLP-1 receptor (GLP-1R). Little information is available, however, about the subcellular localization and the distribution of the GLP-1R protein in the rat brain. To determine the localization of GLP-1R protein in the rat brain, immunocytochemistry was performed at light and electron microscopic levels. The highest density of GLP-1R-immunoreactivity was observed in the circumventricular organs and regions in the vicinity of these areas like in the arcuate nucleus (ARC) and in the nucleus tractus solitarii (NTS). In addition, GLP-1R-immunreactive (IR) neuronal profiles were also observed in a number of telencephalic, diencephalic and brainstem areas and also in the cerebellum. Ultrastructural examination of GLP-1R-immunoreactivity in energy homeostasis related regions showed that GLP-1R immunoreactivity is associated with the membrane of perikarya and dendrites but GLP-1R can also be observed inside and on the surface of axon varicosities and axon terminals. In conclusion, in this study we provide a detailed map of the GLP-1R-IR structures in the CNS. Furthermore, we demonstrate that in addition to the perikaryonal and dendritic distribution, GLP-1R is also present in axonal profiles suggesting a presynaptic action of GLP-1. The very high concentration of GLP-1R-profiles in the circumventricular organs and in the ARC and NTS suggests that peripheral GLP-1 may influence brain functions via these brain areas.

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“…In our study using a mouse model of ITP, we have used rabbit IgG as an inducer of thrombocytopenia. Although this choice was made for practical reasons (ie, rabbit IgG binds well to human FcγRIIIA), 36 , 37 it is important to acknowledge that rabbit IgG has limitations in mirroring human IgG binding to human FcγRs.…”

Section: Discussionmentioning

confidence: 99%

Human Fc gamma receptor IIIA blockade inhibits platelet destruction in a humanized murine model of ITP

Gil Gonzalez,

Won,

Tawhidi

et al. 2024

Blood Advances

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Fc gamma receptor (FcγR) IIIA is an important receptor for IgG and is involved in immune defense mechanisms as well as tissue destruction in some autoimmune diseases including immune thrombocytopenia (ITP). FcγRIIIA on macrophages can trigger phagocytosis of IgG-sensitized platelets and prior pilot studies observed blockade of FcγRIIIA increased platelet counts in ITP patients. Unfortunately, while blockade of FcγRIIIA in ITP patients increased platelet counts, its engagement by the blocking antibody drove serious adverse inflammatory reactions. These adverse events were postulated to originate from the antibody's Fc and/or bivalent nature. Blockade of human FcγRIIIA in vivo with a monovalent construct lacking an active Fc region has not yet been achieved. To effectively block FcγRIIIA in vivo, we developed a high affinity monovalent single chain variable fragment (scFv) that can bind and block human FcγRIIIA. This scFv (17C02) was expressed in three formats: a monovalent fusion protein with albumin, a one-armed human IgG1 antibody, and a standard bivalent mouse (IgG2a) antibody. Both monovalent formats were effective in preventing phagocytosis of ITP-serum-sensitized human platelets. In vivo studies using FcγR-humanized mice demonstrated that both monovalent therapeutics were also able to increase platelet counts. The monovalent albumin fusion protein did not have adverse event activity as assessed by changes in body temperature while the one-armed antibody induced some changes in body temperature even though the Fc region function was impaired by the LALA mutation. These data demonstrate that monovalent blockade of human FcγRIIIA in vivo can potentially be a therapeutic strategy for patients with ITP.

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Binding affinities of human IgG1 and chimerized pig and rabbit derivatives to human, pig and rabbit Fc gamma receptor IIIA

Cited by 4 publications

References 37 publications

Cross-species higher sensitivities of FcγRIIIA/FcγRIV to afucosylated IgG for enhanced ADCC

Cross-species higher sensitivities of FcγRIIIA/FcγRIV to afucosylated IgG for enhanced ADCC

Distribution and ultrastructural localization of the glucagon-like peptide-1 receptor (GLP-1R) in the rat brain

Human Fc gamma receptor IIIA blockade inhibits platelet destruction in a humanized murine model of ITP

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