PolySciTech (www.polyscitech.com)
provides a wide array of PLGA polymers and related block copolymers. Recent
research with PLGA’s have found that lipid-coated microparticles of PLGA that
have antigen present on the surface cause a strong immune response in mice due
to their ability to shed the lipid layer antigens into the lymph nodes. Read
more: Hanson, Melissa C., Anna Bershteyn, Monica P. Crespo, and Darrell J.
Irvine. "Antigen delivery by lipid-enveloped PLGA microparticle vaccines
mediated by in situ vesicle shedding." Biomacromolecules (2014). http://pubs.acs.org/doi/abs/10.1021/bm500337r
“Abstract: Lipid-coated poly(lactide-co-glycolide)
microparticles (LCMPs) consist of a solid polymer core wrapped by a surface
lipid bilayer. Previous studies demonstrated that immunization with LCMPs surface-decorated
with nanograms of antigen elicit potent humoral immune responses in mice.
However, the mechanism of action for these vaccines remained unclear, as LCMPs
are too large to drain efficiently to lymph nodes from the vaccination site.
Here, we characterized the stability of the lipid envelope of LCMPs and
discovered that in the presence of serum the lipid coating of the particles
spontaneously delaminates, shedding antigen-displaying vesicles. Lipid
delamination generated 180 nm liposomes in a temperature- and
lipid/serum-dependent manner. Vesicle shedding was restricted by inclusion of
high-TM lipids or cholesterol in the LCMP coating. Administration of LCMPs
bearing stabilized lipid envelopes generated weaker antibody responses than
those of shedding-competent LCMPs, suggesting that in situ release of
antigen-loaded vesicles plays a key role in the remarkable potency of LCMPs as
vaccine adjuvants.”
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