Influence of surface charge of PLGA particles of recombinant hepatitis B surface antigen in enhancing systemic and mucosal immune responses
Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 Coulter, Amarillo, TX 79106, United States. International Journal of Pharmaceutics
(Impact Factor: 3.65).
07/2009; 379(1):41-50. DOI: 10.1016/j.ijpharm.2009.06.006
This study investigates the efficacy of surface-modified microspheres of hepatitis B surface antigen (HBsAg) in eliciting systemic and mucosal immune responses. Positively charged poly(D,L-lactic-co-glycolic acid) microspheres were prepared by a double-emulsion solvent-evaporation method with cationic agents--stearylamine and polyethylenimine--in the external aqueous phase. Formulations were characterized for morphology, size, density, aerodynamic diameter, entrapment efficiency and in vitro drug-release profile. Immunization was performed after pulmonary administration of the formulations to female Sprague-Dawley rats and the immune response was monitored by measuring IgG levels in serum and secretory (sIgA) levels in salivary, vaginal and bronchoalveolar lavage fluids. The cell-mediated immune response was studied by measuring cytokine levels in spleen homogenates, and a cytotoxicity study was performed with Calu-3 cell line. The aerodynamic diameter of the particles was within the respirable range, with the exception of stearylamine-modified particles. Zeta potential values moved from negative (-6.76 mV) for unmodified formulations to positive (+0.515 mV) for polyethylenimine-modified particles. Compared to unmodified formulations, polyethylenimine-based formulations showed continuous release of antigen over a period of 28-42 days and increased levels of IgG in serum and sIgA in salivary, vaginal and bronchoalveolar lavage. Further, cytokine levels-interferon gamma and interleukin-2-were increased in spleen homogenates. The viability of Calu-3 cells was not adversely affected by the microparticles. In summation, this study establishes that positive surface charges on poly(D,L-lactic-co-glycolic acid) particles containing HBsAg enhances both the systemic and mucosal immune response upon immunization via the respiratory route.
Available from: Khuloud T Al-Jamal
- "Previous studies have also demonstrated a correlation between enhanced cellular uptake of positively charged particulate vaccine delivery systems and immune response augmentation. For instance, cationic poly-L-lysine coated nanoparticles (1000 nm in diameter) in vitro , polystyrene spheres (1000 nm) in vitro , liposomes (200 nm) of varying lipid composition and surface charges in vitro , PLGA microspheres loaded with hepatitis B Ag (HBAg) in vivo , tetanus toxoid-loaded chitosan nanoparticles (40–400 nm) in vivo  or OVA-conjugated rod-shaped hydrogel nanoparticles in vitro and in vivo . The positively charged L + (OVA) and L + (SIN) showed lower immune response intensity compared to the negatively charged S −/ + (OVA) and S −/+ (SIN), respectively. "
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ABSTRACT: Carbon nanotubes (CNTs) have shown marked capabilities in enhancing antigen delivery to antigen presenting cells. However, proper understanding of how altering the physical properties of CNTs may influence antigen uptake by antigen presenting cells, such as dendritic cells (DCs), has not been established yet. We hypothesized that altering the physical properties of multi-walled CNTs (MWNTs)-antigen conjugates, e.g. length and surface charge, can affect the internalization of MWNT-antigen by DCs, hence the induced immune response potency. For this purpose, pristine MWNTs (p-MWNTs) were exposed to various chemical reactions to modify their physical properties then conjugated to ovalbumin (OVA), a model antigen. The yielded MWNTs-OVA conjugates were long MWNT-OVA (~ 386 nm), bearing net positive charge (5.8 mV), or short MWNTs-OVA (~ 122 nm) of increasing negative charges (− 23.4, − 35.8 or − 39 mV). Compared to the short MWNTs-OVA bearing high negative charges, short MWNT-OVA with the lowest negative charge demonstrated better cellular uptake and OVA-specific immune response both in vitro and in vivo. However, long positively-charged MWNT-OVA showed limited cellular uptake and OVA specific immune response in contrast to short MWNT-OVA displaying the least negative charge. We suggest that reduction in charge negativity of MWNT-antigen conjugate enhances cellular uptake and thus the elicited immune response intensity. Nevertheless, length of MWNT-antigen conjugate might also affect the cellular uptake and immune response potency; highlighting the importance of physical properties as a consideration in designing a MWNT-based vaccine delivery system.
Available from: M. Zheng
- "Polymer nanoparticles, such as polyethylenimine (PEI)  , chitosan  , and polyglycolic acid (PLGA)    have been frequently used as drug and gene delivery in the recent researches. Metallic and ceramic nanoparticles, such as Au nanoparticles    , iron oxide    and silica nanoparticles   , have also been studied for drug and gene delivery. "
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ABSTRACT: In this paper, it aims to build the relationship of statically electric interaction between the surface charge of a particle drug and cellular uptake. The statically electric theory is applied to study the change of wetting between the drug particle and the cell, a factor that enhanced uptake of cells induced by particle’s surface charge is introduced, then it is formulated according to Kelvin theory
for dissolving of solid particle in liquid. It is found that the change of contact angle between the surface charged particle drug and the cell can be detected if the Zeta potential
reaches to 6 mV in water like solution, an increase of about 11.1% for the uptake could be obtained for a polymer particle with molar mass M∼10 kg/mol, mass density ρ∼0.9 × 103 kg/m3, radius r∼15 nm at temperature 300 K and Zeta potential 10 mV condition as compared with the same
particle in water-like solution but without surface charge. The effect of particle surface charge on drug uptake could be interpreted by statically electric theory.
Available from: Ming-Kung Yeh
- "Rosli et al37 demonstrated that the transgene protein expression and IgA antibody responses at local mucosal sites suggest immunological response to a potential oral DNA vaccine formulated within the microsphere carriers. Thomas et al38 reported that the surface charge of microspheres as indicated by the zeta potential has a significant effect on its uptake by phagocytic cells of the immune system. They reported that the further the potential is from zero or greater the absolute value of the zeta potential of the particle, the more effective are their uptake. "
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ABSTRACT: Yersinia pestis F1 antigen-loaded poly(DL-lactide-co-glycolide)/polyethylene glycol (PEG) (PLGA/PEG) microspheres were produced using a water-in-oil-in-water emulsion/solvent extraction technique and assayed for their percent yield, entrapment efficiency, surface morphology, particle size, zeta potential, in vitro release properties, and in vivo animal protect efficacy. The Y. pestis F1 antigen-loaded microspheres (mean particle size 3.8 μm) exhibited a high loading capacity (4.5% w/w), yield (85.2%), and entrapment efficiency (38.1%), and presented a controlled in vitro release profile with a low initial burst (18.5%), then continued to release Y. pestis F1 antigen over 70 days. The distribution (%) of Y. pestis F1 on the microspheres surface, outer layer, and core was 3.1%, 28.9%, and 60.7%, respectively. A steady release rate was noticed to be 0.55 μg Y. pestis F1 antigen/mg microspheres/day of Y. pestis F1 antigen release maintained for 42 days. The cumulative release amount at the 1st, 28th, and 42nd days was 8.2, 26.7, and 31.0 μg Y. pestis F1 antigen/mg microspheres, respectively. The 100 times median lethal dose 50% (LD50) of Y. pestis Yokohama-R strain by intraperitoneal injection challenge in mice test, in which mice received one dose of 40 μg F1 antigen content of PLGA/PEG microspheres, F1 antigen in Al(OH)3, and in comparison with F1 antigen in Al(OH)3 vaccine in two doses, was evaluated after given by subcutaneous immunization of BALB/c mice. The study results show that the greatest survival was observed in the group of mice immunized with one dose of F1 antigen-loaded PLGA/PEG microspheres, and two doses of F1 antigen in Al(OH)3 vaccine (100%). In vivo vaccination studies also demonstrated that F1 vaccines microspheres had a protective ability; its steady-state IgG immune protection in mice plasma dramatic increased from 2 weeks (18,764±3,124) to 7 weeks (126,468±19,176) after vaccination. These findings strongly suggest that F1-antigen loaded microspheres vaccine offer a new therapeutic strategy in optimizing the vaccine incorporation and delivery properties of these potential vaccine targeting carriers.
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