A Stealthiness Evaluation of Main Chain Carboxybetaine Polymer Modified into Liposome.

Acrylamide polymers with zwitterionic carboxybetaine (CB) side groups have attracted attention as stealth polymers that do not induce antibodies when conjugated to proteins. However, they induce antibodies when modified onto liposomes. We hypothesized that antibodies are produced against polymer backbones rather than CB side groups.

Peritoneal B Cells Play a Role in the Production of Anti-polyethylene Glycol (PEG) IgM against Intravenously Injected siRNA-PEGylated Liposome Complexes.

Polyethylene glycol (PEG)-modified (PEGylated) cationic liposomes are frequently used as delivery vehicles for small interfering RNA (siRNA)-based drugs because of their ability to encapsulate/complex with siRNA and prolong the circulation half-life in vivo. Nevertheless, we have reported that subsequent intravenous (IV) injections of siRNA complexed with PEGylated cationic liposomes (PLpx) induces the production of anti-PEG immunoglobulin M (IgM), which accelerates the blood clearance of subsequent doses of PLpx and other PEGylated products. In this study, it is interesting that splenectomy (removal of spleen) did not prevent anti-PEG IgM induction by IV injection of PLpx.

Impact of Anti-PEG IgM Induced via the Topical Application of a Cosmetic Product Containing PEG Derivatives on the Antitumor Effects of PEGylated Liposomal Antitumor Drug Formulations in Mice.

Poly(ethylene glycol) (PEG) is used in many common products, such as cosmetics. PEG, however, is also used to covalently conjugate drug molecules, proteins, or nanocarriers, which is termed PEGylation, to serve as a shield against the natural immune system of the human body. Repeated administration of some PEGylated products, however, is known to induce anti-PEG antibodies.

Treatment-induced and Pre-existing Anti-peg Antibodies: Prevalence, Clinical Implications, and Future Perspectives.

Polyethylene glycol (PEG) is a versatile polymer that is used in numerous pharmaceutical applications like the food industry, a wide range of disinfectants, cosmetics, and many commonly used household products. PEGylation is the term used to describe the covalent attachment of PEG molecules to nanocarriers, proteins and peptides, and it is used to prolong the circulation half-life of the PEGylated products. Consequently, PEGylation improves the efficacy of PEGylated therapeutics.

Anti-PEG IgM production induced by PEGylated liposomes as a function of administration route.

Modifying the surface of nanoparticles with polyethylene glycol (PEG) is a commonly used approach for improving the in vitro stability of nanoparticles such as liposomes and increasing their circulation half-lives. We have demonstrated that, in certain conditions, an intravenous (i.v.

Anti-PEG IgM production and accelerated blood clearance phenomenon after the administration of PEGylated exosomes in mice.

Recently, there is an increasing interest in exosomes or extracellular vesicles as potential candidates for delivering RNAs, proteins, genes, and anticancer agents. Engineering of exosome properties is rapidly evolving as a means of expanding exosome applications. PEGylation of exosomes is a technique used to improve their in vivo stability, circulation half-lives, and sometimes to allow the binding targeting ligands to the exosome exterior.

Incorporating Gangliosides into PEGylated Cationic Liposomes that Complexed DNA Attenuates Anti-PEG Antibody Production but Not Anti-DNA Antibody Production in Mice.

Gangliosides (glycosphingolipids) reduce antibody production by inhibiting B-cell receptor (BCR) signaling. We have shown that a copresentation of gangliosides and polyethylene glycol (PEG) on the same liposomes suppresses anti-PEG IgM production in mice. In addition, we recently observed that pDNA incorporated in PEGylated cationic liposomes (PCLs) induces anti-DNA IgM, which could be a hurdle to the development of efficient gene delivery systems.

Nucleic acids delivered by PEGylated cationic liposomes in systemic lupus erythematosus-prone mice: A possible exacerbation of lupus nephritis in the presence of pre-existing anti-nucleic acid antibodies.

Nucleic acid-based therapy with plasmid DNA (pDNA) and small interfering RNA (siRNA) have received recent attention for their ability to modulate the cellular expression of genes and proteins. Polyethylene glycol-modified (PEGylated) cationic nanoparticles have been used as non-viral vectors for the in vivo delivery of these nucleic acids. We have reported that PEGylated cationic liposomes (PCL) including pDNA or siRNA induce anti-PEG antibodies upon repeated intravenous injection, leading to the formation of immune complexes and enhanced clearance from the blood of subsequent doses.

Impact of Pre-Existing or Induced Anti-PEG IgM on the Pharmacokinetics of Peginterferon Alfa-2a (Pegasys) in Mice.

PEGylation had been used successfully to improve the circulation half-lives and some physicochemical properties of protein therapeutics. However, anti-polyethylene glycol (anti-PEG) antibodies, either pre-existing or treatment-induced, can negatively affect the pharmacokinetics and pharmacological efficacy of PEGylated proteins. We have examined anti-PEG immune responses in mice for peginterferon alfa-2a (Pegasys), a clinically approved PEGylated protein therapeutic, at both the recommended dose (equivalent to 3 μg/kg in mice) and at higher doses (150 μg/kg) for single or repeated subcutaneous (s.

Pegfilgrastim (PEG-G-CSF) induces anti-PEG IgM in a dose dependent manner and causes the accelerated blood clearance (ABC) phenomenon upon repeated administration in mice.

Pegfilgrastimis a recombinant PEGylated human granulocyte colony-stimulating factor (G-CSF) analog filgrastim (trade names Neulasta® or G-Lasta®) that stimulates the production of white blood cells (neutrophils). It is employed as an alternative to filgrastim (G-CSF) for chemotherapy-induced neutropenia in patients due to its longer half-life. In clinical settings, PEG-G-CSF is administered to cancer patients via both the s.

Hepatosplenic phagocytic cells indirectly contribute to anti-PEG IgM production in the accelerated blood clearance (ABC) phenomenon against PEGylated liposomes: Appearance of an unexplained mechanism in the ABC phenomenon.

The accelerated blood clearance (ABC) phenomenon, caused in large degree via in vivo anti-PEG IgM production, is one of obstacles for development of PEGylated liposome and protein formulations, due to decreased efficiency and/or side effects such as anaphylaxis upon repeat administrations. We have shown in murine ABC models that splenectomy suppressed the level of anti-PEG IgM production induced by PEGylated liposomes, indicating that murine splenic B cells play an important role in its production. However, splenectomy did not completely inhibit production of anti-PEG IgM, suggesting that other cells may contribute to its production in the ABC phenomenon.