Anti-PEG antibodies alter the mobility and biodistribution of densely PEGylated nanoparticles in mucus

Abstract

Antibodies that specifically bind polyethylene glycol (PEG) can lead to rapid elimination of PEGylated therapeutics from the systemic circulation. We have recently shown that virus-binding IgG can immobilize viruses in mucus via multiple low-affinity crosslinks between IgG and mucins. However, it remains unclear whether anti-PEG antibodies in mucus may also alter the penetration and consequently biodistribution of PEGylated nanoparticles delivered to mucosal surfaces. We found that both anti-PEG IgG and IgM can readily bind nanoparticles that were densely coated with PEG polymer to minimize adhesive interactions with mucus constituents. Addition of anti-PEG IgG and IgM into mouse cervicovaginal mucus resulted in extensive trapping of mucus-penetrating PEGylated nanoparticles, with the fraction of mobile particles reduced from over 95% to only 34% and 7% with anti-PEG IgG and IgM, respectively. Surprisingly, we did not observe significant agglutination induced by either antibody, suggesting that particle immobilization is caused by adhesive crosslinks between mucin fibers and IgG or IgM bound to individual nanoparticles. Importantly, addition of corresponding control antibodies did not slow the PEGylated nanoparticles, confirming anti-PEG antibodies specifically bound to and trapped the PEGylated nanoparticles. Finally, we showed that trapped PEGylated nanoparticles remained largely in the luminal mucus layer of the mouse vagina even when delivered in hypotonic formulations that caused untrapped particles to be drawn by the flow of water (advection) through mucus all the way to the epithelial surface. These results underscore the potential importance of elucidating mucosal anti-PEG immune responses for PEGylated therapeutics and biomaterials applied to mucosal surfaces.

The particle in the spider's web: transport through biological hydrogels

“…169 As mucosal anti-PEG antibodies may be common in the human population but are probably not present in animal mucus models, antibody-mediated trapping (and immunogenicity of PEG in general 170 ) is a potential hurdle for clinical applications of PEGylated nanoparticles. 169 …”

A slippery slope: On the origin, role and physiology of mucus

“…Furthermore, it has been shown that hypo tonicity of the applied formulation improves distribution and diffusion of the particles through the cervicovaginal mucus [206,207]. On the other hand, it has been recently highlighted the possibility to generate anti-PEG IgG and IgM, which can cross-link PEG coated particles limiting its diffusion through mouse cervicovaginal mucus, even when the particles are prepared as hypotonic suspension [208].…”

Engineering highly multivalent sperm-binding IgG antibodies for potent non-hormonal female contraception

“…First, at high sperm concentration, ASA can agglutinate sperm into clusters that are too large to penetrate mucus, a process particularly potent with polymeric antibodies (Abs) such as IgM [10][11][12] . Second, at lower sperm concentration, ASA can trap individual spermatozoa in mucus by forming multiple low affinity Fcmucin bonds between sperm-bound ASA and mucin fibers [13][14][15] . Years ago, these observations motivated the development of contraceptive vaccines [16][17][18][19] .…”