Extending human IgG half-life using structure-guided design

Booth, Brian J.; Ramakrishnan, B.; Narayan, Kristin; Wollacott, Andrew M.; Babcock, Gregory J.; Shriver, Zachary; Viswanathan, Karthik

doi:10.1080/19420862.2018.1490119

Cited by 70 publications

(74 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To further assess the putative Fab and FcRn interactions, we analyzed the IgG-FcRn complex structure by negative stain electron microscopy, and observed several distinct classifications of IgG-FcRn complex ( Figure 2 ). The Fab arms of IgG appear to be highly dynamic as previously observed, 31 with multiple conformations previously predicted by Booth et al 32 These include the canonical Y-shaped conformation ( Figure 2(a and d )), a T-shaped conformation ( Figure 2(b and e )) or a mixed Y/T conformation ( Figure 2(c and f )). In addition, we observed that the soluble form of FcRn can bind to the IgG at either 1:1 ( Figure 2(b -d)) or 2:1 ( Figure 2(e -f)) stoichiometry.…”

Section: Resultssupporting

confidence: 76%

Antigen physiochemical properties allosterically effect the IgG Fc-region and Fc neonatal receptor affinity

Estevez¹,

Schlothauer

Wecksler³

2020

mAbs

View full text Add to dashboard Cite

The neonatal Fc receptor (FcRn) is a key membrane protein that plays an integral role in serum immunoglobulin (IgG) recycling, which extends the half-life of antibody. In addition, FcRn is known to traffic antigen-bound immunoglobulins (Ag-IgGs), and to interact with immune complexes to facilitate the antigen cross-presentation of peptides derived from the immune complexes in antigen-presenting cells (APCs). Studies on the IgG-FcRn molecular interactions have primarily focused on the Fc region, and only recently have shown the potential impact of the antigen-binding fragment physiochemical properties on FcRn binding. However, the effect of the antigen physiochemical properties on IgG structure as it relates to Ag-IgG-FcRn binding is not well understood. Here we used an IgG-peptide antigen complex as a model system to investigate the structural effects of the antigen’s physiochemical properties on the IgG structure, and the subsequent effects of Ag-IgG-FcRn interactions. We used hydroxyl radical footprinting–mass spectrometry to investigate the structural impact on an IgG upon antigen binding, and observed that the physicochemical properties of the antigen differentially induce conformational changes in the IgG FcRn binding region. The extent of these structural changes directly correlates to the magnitude of the affinity differences between the Ag-IgG complexes and FcRn. Moreover, the antigen’s physicochemical properties differentially induce structural differences within the Ag-IgG-FcRn ternary complex. We also provide electron microscopy data that shows corroborating Fab-FcRn interactions, and confirms the hypothesis of potential 2:1 FcRn:IgG binding stoichiometry. These data demonstrate antigen-induced Fc structural rearrangements affect both the affinity toward FcRn and the trimeric antigen-IgG-FcRn complex, providing novel molecular insights in the first steps toward understanding interactions of FcRn-containing large(r)-sized immune complex.

show abstract

Section: Resultssupporting

confidence: 76%

Antigen physiochemical properties allosterically effect the IgG Fc-region and Fc neonatal receptor affinity

Estevez¹,

Schlothauer

Wecksler³

2020

mAbs

View full text Add to dashboard Cite

show abstract

“…Structurally, the Del mutation is well tolerated, as demonstrated by the conserved thermal stability. In this aspect, the Del mutation is an improvement over the well-known FcRn + YTE variant, which increases mAb serum t 1/2 in humans at the cost of highly decreasing the thermal stability of the mAb (83). In addition, as assessed by two in silico algorithms that predict epitope binding to human HLA alleles (Antitope [iTope and TCED] and Lonza [Epibase]), the Del mutation failed to generate neo-epitopes with consensus HLA-binding residues.…”

Section: Discussionmentioning

confidence: 99%

Fc Sialylation Prolongs Serum Half-Life of Therapeutic Antibodies

Bas

Terrier

Jacque³

et al. 2019

The Journal of Immunology

View full text Add to dashboard Cite

The long serum t 1/2 of IgGs is ensured by their interaction with the neonatal Fc receptor (FcRn), which salvages IgG from intracellular degradation. Fc glycosylation is thought not to influence FcRn binding and IgG longevity in vivo. In this article, we demonstrate that hypersialylation of asparagine 297 (N297) enhances IgG serum persistence. This polarized glycosylation is achieved using a novel Fc mutation, a glutamate residue deletion at position 294 (Del) that endows IgGs with an up to 9-fold increase in serum lifespan. The strongest impact was observed when the Del was combined with Fc mutations improving FcRn binding (Del-FcRn +). Enzymatic desialylation of a Del-FcRn + mutant or its production in a cell line unable to hypersialylate reduced the in vivo serum t 1/2 of the desialylated mutants to that of native FcRn + mutants. Consequently, our study proves that sialylation of the N297 sugar moiety has a direct impact on human IgG serum persistence.

show abstract

“…Monoclonal antibodies (mAbs) to CSP have been proposed as new infection-blocking interventions [9][10][11][12], and protection by mAbs can be expected to wane with the half-life of the antibody in serum. While altering the sequence of mAb Fc regions has been used to extend serum half-life of mAbs [13], an important additional approach for improving the durability of protection is to identify mAbs effective at lower concentrations. Identification and development of such potent antibodies will require assays that reliably measure their functional activity.…”

Section: Introductionmentioning

confidence: 99%

Characterization of two in vivo challenge models to measure functional activity of monoclonal antibodies to Plasmodium falciparum circumsporozoite protein

Raghunandan

Mayer

Flores-García

et al. 2020

Malar J

View full text Add to dashboard Cite

Background: New strategies are needed to reduce the incidence of malaria, and promising approaches include the development of vaccines and monoclonal antibodies (mAbs) that target the circumsporozoite protein (CSP). To select the best candidates and speed development, it is essential to standardize preclinical assays to measure the potency of such interventions in animal models. Methods: Two assay configurations were studied using transgenic Plasmodium berghei expressing Plasmodium falciparum full-length circumsporozoite protein. The assays measured (1) reduction in parasite infection of the liver (liver burden) following an intravenous (i.v) administration of sporozoites and (2) protection from parasitaemia following mosquito bite challenge. Two human CSP mAbs, AB311 and AB317, were compared for their ability to inhibit infection. Multiple independent experiments were conducted to define assay variability and resultant impact on the ability to discriminate differences in mAb functional activity. Results: Overall, the assays produced highly consistent results in that all individual experiments showed greater functional activity for AB317 compared to AB311 as calculated by the dose required for 50% inhibition (ID50) as well as the serum concentration required for 50% inhibition (IC50). The data were then used to model experimental designs with adequate statistical power to rigorously screen, compare, and rank order novel anti-CSP mAbs. Conclusion: The results indicate that in vivo assays described here can provide reliable information for comparing the functional activity of mAbs. The results also provide guidance regarding selection of the appropriate experimental design, dose selection, and group sizes.

show abstract

Extending human IgG half-life using structure-guided design

Cited by 70 publications

References 54 publications

Antigen physiochemical properties allosterically effect the IgG Fc-region and Fc neonatal receptor affinity

Antigen physiochemical properties allosterically effect the IgG Fc-region and Fc neonatal receptor affinity

Fc Sialylation Prolongs Serum Half-Life of Therapeutic Antibodies

Characterization of two in vivo challenge models to measure functional activity of monoclonal antibodies to Plasmodium falciparum circumsporozoite protein

Contact Info

Product

Resources

About