Zwitterionic gel encapsulation promotes protein stability, enhances pharmacokinetics, and reduces immunogenicity

Abstract

Advances in protein therapy are hindered by the poor stability, inadequate pharmacokinetic (PK) profiles, and immunogenicity of many therapeutic proteins. Polyethylene glycol conjugation (PEGylation) is the most successful strategy to date to overcome these shortcomings, and more than 10 PEGylated proteins have been brought to market. However, anti-PEG antibodies induced by treatment raise serious concerns about the future of PEGylated therapeutics. Here, we demonstrate a zwitterionic polymer network encapsulation technology that effectively enhances protein stability and PK while mitigating the immune response. Uricase modified with a comprehensive zwitterionic polycarboxybetaine (PCB) network exhibited exceptional stability and a greatly prolonged circulation half-life. More importantly, the PK behavior was unchanged, and neither anti-uricase nor anti-PCB antibodies were detected after three weekly injections in a rat model. This technology is applicable to a variety of proteins and unlocks the possibility of adopting highly immunogenic proteins for therapeutic or protective applications.protein delivery | immune response | zwitterionic polymer | hydrogel | nanomedicine

Zwitterionic polymer-protein conjugates reduce polymer-specific antibody response

“…Previous work has highlighted the presence of polymerspecific antibodies [8][9][10][11]14,15,[27][28][29], which continued to mediate immune clearance in addition to any generated toward the protein itself. To detect and compare the possible antibodies generated against polyzwitterions vs. PEG, we prepared rat proteins conjugated with either polymer at similar densities.…”

“…While many types of polyzwitterions exist, such as poly(phosphorylcholine), poly(sulfobetaine), and poly(carboxybetaine), we focus on the last group as it contains the naturally occurring glycine betaine and was shown to maintain protein stability and bioactivity as demonstrated in our previous studies [22]. These polymers as components of nanoparticles (NPs) demonstrated excellent long-circulation abilities, often yielding half-lives multiple times longer than the equivalent PEG NP [23][24][25][26][27][28]. At the same time, polymer-specific antibodies were absent, while anti-PEG antibodies were clearly detected and quantified [27,28].…”

“…These polymers as components of nanoparticles (NPs) demonstrated excellent long-circulation abilities, often yielding half-lives multiple times longer than the equivalent PEG NP [23][24][25][26][27][28]. At the same time, polymer-specific antibodies were absent, while anti-PEG antibodies were clearly detected and quantified [27,28]. Furthermore, protein conjugates studied in vitro showed maintenance or improved stability of the underlying protein without reducing bioactivity or binding affinity [22].…”

The early days of PEG and PEGylation (1970s–1990s)

“…Further, Shaoyi Jiang, et el. have shown that a polymer with pendant zwitter-ion groups may provide protection to ''fragile" (biomolecular) drugs, without the potential immunogenic properties that some PEGylated drugs may exhibit, as described above [29][30][31][32][33]. The zwitter-ion groups are highly hydrated, and bind water molecules strongly.…”

Antifouling zwitterionic hydrogel coating improves hemocompatibility of activated carbon hemoadsorbent

“…This also proved the excellent permeability of PCB hydrogel to nutrients and cell wastes [28]. In more recent studies, PCB hydrogel was shown to resist the foreign body reaction when implanted in mice and effectively enhance protein stability [29][30][31]. These findings motivated us to explore the application of PCB hydrogel as the coating material for activated carbon particles.…”