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.
"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. "
[Show abstract][Hide abstract] 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.
International Journal of Nanomedicine 02/2014; 9(1):813-22. DOI:10.2147/IJN.S56260 · 4.38 Impact Factor
"It has been concluded that positively charged vaccine vector carrying DNA elicited an intense toxic response of T-lymphocytes . Furthermore, poly(d,l-lactide-co-glycolide) microspheres with positive surface charge induced strong humoral and mucosal immune responses . Therefore, the interaction between cationic surface and human cells played an important role in the cytotoxic impact of CSLNs. "
[Show abstract][Hide abstract] ABSTRACT: Application of cationic solid lipid nanoparticles (CSLNs), comprising complex internal matrix and lipid-regulated external surface, is an intriguing issue in current bionanotechnology. This study presents dissolution kinetics of saquinavir (SQV) from CSLNs with cholesterol-mediated esterquat 1 (EQ 1) and biocompatibility of SQV-loaded CSLNs with human brain-microvascular endothelial cells (HBMECs). CSLNs with SQV in lipid cores containing cholesterol were dissolved and incubated with HBMECs. The results revealed that an increase in the weight percentage of EQ 1 reduced the entrapment efficiency of SQV. In addition, the entrapment efficiency of SQV enhanced, when the weight percentage of cholesterol increased from 0% to 25% (w/w). The reverse was true when cholesterol increased from 0% to 75% (w/w). The dissolution profiles demonstrated that the mediation of cholesterol favored the sustained release of SQV. When the weight percentage of EQ 1 increased, the viability of HBMECs enhanced. An increase in the weight percentage of cholesterol, however, reduced the viability of HBMECs. The innovated CSLNs containing cholesterol can be effective in controlled release of SQV without inducing significant endothelial toxicity.
"uscular administration of the vaccine ( Singh et al . , 2001 ) . Nanoparticles prepared from PLGA [ poly ( DL - lactide - co - glycolide ) ] containing hepatitis B , rotavirus , influenza or parainfluenza virus delivered to mucosal sites of mice generated protective immunity ( Singh et al . , 2001 ; Shephard et al . , 2003 ; Nayak et al . , 2009 ; Thomas et al . , 2009 ) . Biodegradable and bio - compatible PLGA nanoparticles are free from any toxicity in animals and humans , they are safe for use in humans , and are approved by the U . S . Food and Drug Adminis - tration ( Duncan , 2005 ; McNeil , 2005 ; Semete et al . , 2010 ) ."
[Show abstract][Hide abstract] ABSTRACT: Porcine reproductive and respiratory syndrome (PRRS) is an economically important infectious disease of swine. Constant emergence of variant strains of PRRS virus (PPRSV) and virus-mediated immune evasion followed by viral persistence result in increased incidence and recurrence of PRRS in swine herds. Current live and killed PRRSV vaccines administered by a parenteral route are ineffective in inducing complete protection. Thus, new approaches in design and delivery of PRRSV vaccines are needed to reduce the disease burden of the swine industry. Induction of an effective mucosal immunity to several respiratory pathogens by direct delivery of a vaccine to mucosal sites has proven to be effective in a mouse model. However, there are challenges in eliciting mucosal immunity to PRRS due to our limited understanding of safe and potent mucosal adjuvants, which could potentiate the mucosal immune response to PRRSV. The purpose of this review is to discuss methods for induction of protective mucosal immune responses in the respiratory tract of pigs. The manuscript also discusses how PRRSV modulates innate, adaptive and immunoregulatory responses at both mucosal and systemic sites of infected and/or vaccinated pigs. This information may help in the design of innovative mucosal vaccines to elicit superior cross-protective immunity against divergent field strains of PRRSV.
Animal Health Research Reviews 05/2012; 13(1):21-37. DOI:10.1017/S1466252312000023
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