ABSTRACT
Background: Cationic immune stimulating complexes [PLUSCOMs] are particulate antigen delivery systems. PLUSCOMs consist of cationic immunostimulatory complexes [ISCOMs] derivatives and are able to elicit in vivo T cell responses against an antigen
Objective: To evaluate the effects of PLUSCOMs containing Leishmania major antigens [SLA] on the type of immune response generated in the murine model of leishmaniasis
Methods: PLUSCOMs consisting of 1, 2-dioleoyl-3-trimethylammonium-propane [DOTAP] were used as antigen delivery system/immunoadjuvants for soluble SLA. BALB/c mice were immunized subcutaneously, three times in 2-week intervals. Footpads swellings at the site of challenge and parasite loads were assessed as a measure of protection. The immune responses were also evaluated by determination of IgG subclasses and the level of IFN- gamma and IL-4 in cultured splenocytes
Results: There was no significant difference [p<0.05] between the sizes of lesions in mice immunized with different formulations. Also, there was no significant difference in the number of parasites in the footpad or spleen of all groups compared with the control group. The highest level of IFN- gamma secretion was observed in the splenocytes of mice immunized with PLUSCOM/SLA [p<0.001] and lower amounts of IL-4 was observed in PLUSCOM group [p<0.001] as compared to negative control
Conclusion: Our results indicated that SLA in different formulations generated an immune response with mixed Th1/Th2 response that was not protective enough despite the activation of CD4+ T cells with secreting IFN- gamma in groups which received PLUSCOM with antigen
ABSTRACT
Lipid-based nanoparticles [NLP] are PEGylated carriers composed of lipids and encapsulated nucleic acids with a diameter less than 100 nm. The presence of PEG in the NLP formulation improves the particle pharmacokinetic behavior. The purpose of this study was to prepare and characterize NLPs containing MDR1 siRNA and evaluate their cytotoxicity and cellular uptake. MDR1 siRNA could be used in multidrug resistance reversal in cancer therapy. siRNAs were encapsulated into NLPs consisted of mPEG-DSPE/DOTAP/DOPE [10:50:40 molar ratio] by the detergent dialysis method. The particle diameters of NLPs and their surface charge were measured using dynamic light scattering. siRNA encapsulation efficiency was determined by an indirect method via filtration and free siRNA concentration determination. NLPs cytotoxicity was investigated by MTT assay. The ability of NLPs for siRNA delivery checked in two human cell lines [MCF-7/ADR and EPP85-181/RDB] by fluorescence microscopy and compared with oligofectamine. NLPs containing MDR1 siRNA were prepared with the stable size of 80-90 nm and the zeta potential near to neutral. The siRNA encapsulation efficacy was more than 80%. These properties are suitable for in vivo siRNA delivery. NLPs cytotoxicity studies demonstrated they were non-toxic at the doses used. NLPs improved siRNA localization in both cell lines. NLPs containing MDR1 siRNA can be a good candidate for in vivo siRNA delivery studies
Subject(s)
Humans , RNA, Small Interfering , Lipids , Nanoparticles , Liposomes , Genetic TherapyABSTRACT
The purpose of this study was to optimize a method for the encapsulation of P5 peptide, a new designed peptide containing MHC class I epitopes from rat HER2/neu protein, into liposomes as an approach for breast cancer vaccine formulation. The efficiency of liposomal encapsulation of peptides is generally low and development of an optimized method to increase encapsulation efficiency is a big challenge. In this study, P5 peptide was encapsulated into liposomes using the following three different methods based on film-hydration procedure. In method A, the lipid film containing P5 was hydrated using buffer and then extruded to 100 nm using polycarbonate filter. In method B all the steps were the same as method A, except that the lipid film was hydrated in buffer containing 10% [v/v] of DMSO and P5 peptide. In method C, P5 peptide was added to preformed liposomes [40 mM] in the presence of ethanol [30% v/v] and incubated at 25 [degree sign]C for 1h. The highest peptide encapsulation efficiency was achieved using method C [44%]. The presence of P5 peptide in purified liposomes was also confirmed using SDS- PAGE analysis. Investigation on the effects of procedure parameters of method C on encapsulation efficiency demonstrated that method is an optimized procedure for encapsulating P5 peptide. Maximal recovery from liposomes for the accurate quantification of peptide was discovered using acidified isopropanol at 1:2 of sample to solvent ratio [v/v]. In conclusion, the optimal methods of encapsulation and peptide content determination in liposomes can accelerate the development of liposomal vaccine formulations
ABSTRACT
An inoculation of virulent Leishmania major is known as leishmanization [LZ] which is proven to be the most effective control measure against Cutaneous Leishmaniasis [CL]. However, using LZ is restricted due to various side effects such as uncontrolled lesion development. In the present research, the efficacy of cationic nanoliposomes containing CpG oligodeoxynucleotides [CpG ODN] as an improved adjuvant delivery system was studied to diminish the lesion development and infection course of L. major after inoculation into the mice. BALB/c mice were inoculated subcutaneously [SC] with L. major plus empty DSPC, DSPC [CpG ODN], DSPC [Non CpG ODN], empty DMPC, DMPC [CpG ODN], DMPC [Non CpG ODN] or HEPES buffer. The results showed that group of mice received DMPC [CpG ODN] nanoliposomes developed a significantly smaller lesion and showed minimum number of L. major in the spleen and draining lymph nodes. In addition, using DMPC [CpG ODN] liposomes resulted in a Th1 type of immune response with a preponderance of IgG2a isotype which is concurrent with the production of DMPC [CpG] induced IFN-gamma in the spleen of the mice. Taken together, the results suggested that immune modulation using DMPC [CpG ODN] nanoliposomes might be a practical approach to improve the safety of LZ