Liposome (Lipodine™)-Mediated Dna Vaccination by the Oral Route

Abstract

Plasmid DNA pRc/CMV HBS encoding the S (small) region of hepatitis B surface antigen (HBsAg) was incorporated by the dehydration-rehydration method into Lipodine liposomes composed of 16 micro moles phosphatidylcholine (PC) or distearoyl phosphatidylcholine (DSPC), 8 micro moles of (dioleoyl phosphatidylethanolamine (DOPE) or cholesterol and 4 micro moles of the cationic lipid 1,2-dioleoyl-3-(trimethylammonium propane (DOTAP) (molar ratios 1 : 0.5 : 0.25). Incorporation efficiency was high (89-93% of the amount of DNA used) in all four formulations tested and incorporated DNA was shown to be resistant to displacement in the presence of the competing anionic sodium dodecyl sulphate molecules. This is consistent with the notion that most of the DNA is incorporated within the multilamellar vesicles structure rather than being vesicle surface-complexed. Stability studies performed in simulated intestinal media also demonstrated that dehydration-rehydration vesicles (DRV) incorporating DNA (DRV(DNA)) were able to retain significantly more of their DNA content compared to DNA complexed with preformed small unilamellar vesicles (SUV-DNA) of the same composition. Moreover, after 4h incubation in the media, DNA loss for DSPC DRV(DNA) was only minimal, suggesting this to be the most stable formulation. Oral (intragastric) liposome-mediated DNA immunisation studies employing a variety of DRV(DNA) formulations as well as naked DNA revealed that secreted IgA responses against the encoded HBsAg were (as early as three weeks after the first dose) substantially higher after dosing with 100 micro g liposome-entrapped DNA compared to naked DNA. Throughout the fourteen week investigation, IgA responses in mice were consistently higher with the DSPC DRV(DNA) liposomes compared to naked DNA and correlated well with their improved DNA retention when exposed to model intestinal fluids. To investigate gene expression after oral (intragastric) administration, mice were given 100 micro g of naked or DSPC DRV liposome-entrapped plasmid DNA expressing the enhanced green fluorescent protein (pCMV.EGFP). Expression of the gene, in terms of fluorescence intensity in the draining mesenteric lymph nodes, was much greater in mice dosed with liposomal DNA than in animals dosed with the naked DNA. These results suggest that DSPC DRV liposomes containing DNA (Lipodine) may be a useful system for the oral delivery of DNA vaccines.

Nanogram Doses of Alum-Adjuvanted HBs Antigen Induce Humoral Immune Response in Mice When Orally Administered

“…Live attenuated prototype oral vaccines based on recombined vaccinia virus and adenovirus expressing the HBV surface antigen (HBs antigen, HBsAg) have proven to be effective in chimpanzee tests (Lubeck et al 1989;Moss et al 1984). An orally administered purified HBs antigen carried in stabilized vesicles (Borges et al 2007;Shukla et al 2008) as well as HBs-coding DNA immunization (McCluskie et al 1999;Perrie et al 2002) also stimulated an anti-HBs response. Many attempts have also been made in the last two decades to develop plant-based vaccines against HBV.…”

“Wrapped Up” Vaccines in the Context of HIV-1 Immunotherapy

“…In mice DNA lipoplexes have been shown to induce antitumor activity [247] and both antibody and Th1 cellular responses against hepatitis C virus [248,249]. In the late eighties the first transfection with mRNA-lipoplexes was performed [250].…”

Recent advances in oral vaccine development

“…14 The categories of particulate antigen delivery systems, including immune stimulating complexes (ISCOMs), liposomes, virus-like particles, micro-and nanoparticles have been widely reviewed in recent literature. [15][16][17][18] In this review, we discuss the challenges regarding the development and design of oral vaccine formulations, focusing on the documented effects of yeastderived β-glucan microparticles as an oral delivery platform.…”