Incorporation of ovalbumin into ISCOMs and related colloidal particles prepared by the lipid film hydration method.
ABSTRACT The aim of this study was to investigate the incorporation of a model antigen, fluorescently labelled ovalbumin (FITC-OVA), into various colloidal particles including immune stimulating complexes (ISCOMs), liposomes, ring and worm-like micelles, lamellae and lipidic/layered structures that are formed from various combinations of the triterpene saponin Quil A, cholesterol and phosphatidylethanolamine (PE) following hydration of PE/cholesterol lipid films with aqueous solutions of Quil A. Colloidal dispersions of these three components were also prepared by the dialysis method for comparison. FITC-OVA was conjugated with palmitic acid (P) and PE to produce P-FITC-OVA and PE-FITC-OVA, respectively. Both P-FITC-OVA and PE-FITC-OVA could be incorporated in all colloidal structures whereas FITC-OVA was incorporated only into liposomes. The incorporation of PE-FITC-OVA into all colloidal structures was significantly higher than P-FITC-OVA (P < 0.05). The degree of incorporation of protein was in the order: ring and worm-like micelles < liposomes and lipidic/layered structures < ISCOMs and lamellae. The incorporation of protein into the various particles prepared by the lipid film hydration method was similar to those for colloidal particles prepared by the dialysis method (provided both methods lead to the formation of the same colloidal structures). In the case of different colloidal structures arising due to the preparation method, differences in encapsulation efficiency were found (P < 0.05) for formulations with the same polar lipid composition. This study demonstrates that the various colloidal particles formed as a result of hydrating PE/cholesterol lipid films with different amounts of Quil A are capable of incorporating antigen, provided it is amphipathic. Some of these colloidal particles may be used as effective vaccine delivery systems.
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Article: ISCOMs and ISCOMATRIX™[show abstract] [hide abstract]
ABSTRACT: Immunostimulatory complexes (ISCOMs) are particulate antigen delivery systems composed of antigen, cholesterol, phospholipid and saponin, while ISCOMATRIX™ is a particulate adjuvant comprising cholesterol, phospholipid and saponin but without antigen. The combination of an antigen with ISCOMATRIX™ is called an ISCOMATRIX™ vaccine. ISCOMs and ISCOMATRIX™ combine the advantages of a particulate carrier system with the presence of an in-built adjuvant (Quil A) and consequently have been found to be more immunogenic, while removing its haemolytic activity of the saponin, producing less toxicity. ISCOMs and ISCOMATRIX™ vaccines have now been shown to induce strong antigen-specific cellular or humoral immune responses to a broad range of antigens of viral, bacterial, parasite origin or tumor in a number of animal species including non-human primates and humans. These vaccines produced by well controlled and reproducible processes have also been evaluated in human clinical trials. In this review, we summarize the recent progress of ISCOMs and ISCOMATRIX™, including preparation technology as well as their application in humans and veterinary vaccine designs with particular emphasis on the current understanding of the properties and features of ISCOMs and ISCOMATRIX™ vaccines to induce immune responses. The mechanisms of adjuvanticity are also discussed in the light of recent findings.Vaccine. 01/2009;
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ABSTRACT: Intranasal immunization was assayed in C57BL/6 mice against Angiostrongylus costaricensis using a synthetic and a recombinant peptide belonging to the catalytic region of the serine/threonine phosphatase 2 A (PP2A) of the parasite. Immunization was carried out with the synthetic peptide (SP) polymerized either with itself or with the beta fraction of the cholera toxin (CTB) and then enclosed in nanocapsules of phosphatidyl choline, cholesterol and Quil A (ISCOM). Another group of mice was immunized with recombinant peptide. Immunization consisted of two intranasal inoculations at two-week intervals, and the challenge with L3 larvae was made one month after the last vaccination. The effectiveness of immunization was evaluated 30 days after infection by analysis of the number of parasites in the arteries of the immunized mice, as well as by measuring spleen sizes in the experimental groups. The response induced was determined by identifying the isotypes of IgG as well as the IgE and IgA specific antigen response. The interleukins produced by the splenocyte culture of the different groups were assessed after exposing them to the peptide used in the immunization. From our results, 60%, 80%, and 100% protection against the A. costaricensis challenge was achieved in mice immunized with polymerized synthetic peptide in ISCOM, synthetic peptide polymerized with the CTB in ISCOM and inclusion bodies respectively. Splenomegaly was found to be less evident in the immunized mice than in the controls. A significant increase in IFN gamma and IL-17 levels was observed in the group with 100% protection. The results showed that vaccination through the nasal mucosa may constitute a useful method of immunization and result in a protective immune response against A. costaricensis.Vaccine 07/2010; 28(32):5185-96. · 3.77 Impact Factor
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ABSTRACT: Advances in vaccine formulation have seen a trend towards the use of subunit antigens, ideally incorporated into particulate carriers. These systems are usually in the nanometer size range to facilitate uptake into antigen-presenting cells and to mimic the nature of pathogens. In addition, adjuvants can be incorporated into the same carrier and therefore result in the simultaneous delivery of antigen and adjuvant to the same antigen-presenting cell. A wide variety of particu-late carriers have been investigated for vaccine delivery ranging from biological-based particles such as bacterial ghosts and virus-like particles to more simple polymer-or lipid-based systems. In this review we will focus on lipid-based par-ticulate carriers as these offer great potential as regards immune stimulation and due to the simple formulation techniques involved are likely to be more easily scaled-up for manufacture. Another advantage of such systems is versatility in that in addition to the subcutaneous administration of these vaccine formulations, there is also potential for transdermal or even oral delivery. Examples of such delivery systems include liposomes, ethosomes, transfersomes, bilosomes, and immune stimulating complexes. The physico-chemical properties of such systems will be reviewed as will their potential to stimu-late immune responses. In addition, we will summarise the recent developments in lipid-based sustained delivery systems for antigens.Current Immunology Reviews - CURR IMMUNOL REV. 01/2009; 5(1).