Composition and Surface Charge of DNA-Loaded Microparticles Determine Maturation and Cytokine Secretion in Human Dendritic Cells

Abstract

Purpose. Biodegradable microparticles prepared from poly(lactide) (PLA) and poly(lactide-co-glycolide) (PLGA) have been shown to be promising carrier systems for vaccine delivery. Here, we have investigated the capacity of different PLA and PLGA microparticle formulations to induce stimulation of human blood monocyte-derived dendritic cells (DCs). Methods. Stimulation of human derived dendritic cells by plain microparticles were compared with microparticles loaded with plasmid DNA or double-stranded salmon DNA either by encapsulation or adsorption to the surface of cationic microparticles. Stimulation of DCs was monitored by the up-regulation of surface maturation markers CD83 and CD86 and the secretion of IL-12 and TNF-␣. Results. Slowly degrading PLA microparticles did not induce any detectable stimulation or activation of DCs. In contrast, fast degrading PLGA microparticles were able to influence DC maturation and cytokine secretion dependent on their surface charge. Anionic PLGA microparticles induced an up-regulation of CD83 and high TNF-␣ secretion, which was further enhanced up to the level of the potent stimulator lipopolysaccharide (LPS) when plasmid DNA was encapsulated. Moreover, the secretion of significant amounts of IL-12 was observed. Cationic PLGA microparticles induced an up-regulation of CD86 and moderate TNF-␣ secretion, but no IL-12 secretion, with no additional effects in the presence of plasmid DNA. Conclusions. The data suggest that the composition and charge of biodegradable DNA-loaded microparticles profoundly influences maturation and cytokine secretion in DCs. Thus, the individual formulation of microparticles used as a vaccine carrier system might considerably influence the profile of the immune response.

Enhancement of poly(orthoester) microspheres for DNA vaccine delivery by blending with poly(ethylenimine)

“…3f). Very slow DNA release from PLGA (on the order of weeks) [18,21] may contribute to the low transfection efficiencies observed with PLGA microspheres even after adding PEI. Additionally, acidic products of PLGA hydrolysis may bind to PEI preventing complexation with DNA or preventing PEI release.…”

“…Our microspheres contained very low but detectable levels of endotoxin (< 10 EU/mg). Other groups have reported similar levels in PLGA microspheres [21]. To control for endotoxin effects on DC maturation, we compared microsphere-mediated activation to activation induced by large quantities of LPS.…”

“…In these reports, incorporation of the cationic molecules increased transfection efficiency and boosted immune responses. Yet the use of PLGA microspheres for gene delivery is still not optimal due to low DNA loading [12], undesirably slow release rates [21,22], and DNAdamaging acidic degradation by-products [23,24].…”

Liposomal or Nanoparticle α-TEA Reduced 66cl-4 Murine Mammary Cancer Burden and Metastasis

“…Some type of tumor specific toxicity is a possibility that warrants further investigation. Support for the second possible explanation comes from studies showing enhancement of antitumor immunity by PLGA nanoparticles used for delivery of vaccine (Jilek et al 2004;Yoshida and Babensee 2004). These studies showed that PLGA when formed into nanoparticles enhanced maturation of monocyte-derived dendritic cells.…”

“…These studies showed that PLGA when formed into nanoparticles enhanced maturation of monocyte-derived dendritic cells. As antigen-presenting cells, mature dendritic cells could enhance antitumor immunity (Jilek et al 2004;McKenna et al 2005;Yoshida and Babensee 2004). To investigate possible immune involvement, immune cell infiltration of tumors from liposome and nanoparticle control groups was evaluated.…”