ABSTRACT
It is estimated that Helicobacter pylori infects the stomachs of over 50% of the world's population and if not treated may cause chronic gastritis, peptic ulcer disease, gastric adenocarcinoma and gastric B-cell lymphoma. The aim of this study was to enhance the mucosal and systemic immune responses against the H. pylori antigens cytotoxin-associated gene A (CagA) and neutrophil-activating protein (NAP), through combinations of mucosal and systemic immunizations in female BALB/c mice. We found that oral or intranasal (i.n.) followed by i.m. immunizations induced significantly higher serum titres against NAP and CagA compared to i.n. alone, oral alone, i.m. alone, i.m. followed by i.n. or i.m. followed by oral immunizations. However, only oral followed by i.m. immunizations induced anti-NAP antibody-secreting cells in the stomach. Moreover, mucosal immunizations alone or in combination with i.m., but not i.m. immunizations alone, induced mucosal immunoglobulin A (IgA) responses in faeces. Any single route or combination of immunization routes with NAP and CagA preferentially induced antigen-specific splenic interleukin-4-secreting cells and far fewer interferon-gamma-secreting cells in the spleen. Moreover, i.n. immunizations alone or in combination with i.m. immunizations induced predominantly serum IgG1 and far less serum IgG2a. Importantly, we found that while both i.n. and i.m. recall immunizations induced similar levels of serum antibody responses, mucosal IgA responses in faeces were only achieved through i.n. recall immunization. Collectively, our data show that mucosal followed by systemic immunization significantly enhanced local and systemic immune responses and that i.n. recall immunization is required to induce both mucosal and systemic memory type responses.
Subject(s)
Antigens, Bacterial/immunology , Bacterial Vaccines/immunology , Helicobacter pylori/immunology , Administration, Oral , Animals , Antibodies, Bacterial/biosynthesis , Antigens, Bacterial/administration & dosage , Enzyme-Linked Immunosorbent Assay , Female , Immunity, Mucosal , Immunization/methods , Immunization Schedule , Immunization, Secondary , Immunologic Memory , Injections, Intramuscular , Mice , Mice, Inbred BALB C , Th1 Cells/immunology , Th2 Cells/immunologyABSTRACT
PURPOSE: Cationic PLG microparticles with adsorbed DNA have previously been shown to efficiently target antigen presenting cells in vivo for generating higher immune responses in comparison to naked DNA. In this study we tried to establish the role of surfactant (CTAB) concentration on the physical behavior of these formulations. METHODS: Cationic PLG microparticle formulations with adsorbed DNA were prepared using a solvent evaporation technique. Formulations with varying CTAB concentrations and a fixed DNA load were prepared. The loading efficiency and 24 h DNA release was evaluated for each formulation. Select formulations were tested in vivo. RESULTS: Higher CTAB concentration correlated with higher DNA binding efficiency on the microparticles and lower in vitro release rates. Surprisingly though, the in vivo performance of formulations with varying CTAB concentration was comparable to one another. CONCLUSIONS: Cationic PLG microparticles with adsorbed DNA, as described here, offer a robust way of enhancing in vivo responses to plasmid DNA.
Subject(s)
Cetrimonium Compounds/pharmacokinetics , DNA/pharmacokinetics , Lactic Acid/pharmacokinetics , Polyglycolic Acid/pharmacokinetics , Polymers/pharmacokinetics , Adsorption/drug effects , Animals , Cations , Cetrimonium , Cetrimonium Compounds/chemistry , DNA/blood , Female , Lactic Acid/blood , Lactic Acid/chemistry , Mice , Mice, Inbred BALB C , Microspheres , Polyesters/chemistry , Polyesters/pharmacokinetics , Polyglycolic Acid/chemistry , Polylactic Acid-Polyglycolic Acid Copolymer , Polymers/chemistryABSTRACT
A novel cationic emulsion was developed to adsorb plasmid DNA and improve intracellular delivery of plasmid DNA upon immunization. The emulsion developed, had a highly uniform particle and charge distribution. Based on observations with cationic microparticles, the cationic emulsion was evaluated in vivo in mice and rabbits with a model HIV-1 pCMVp55 gag DNA. In both these species, the cationic emulsion engendered higher antibody responses than those obtained with naked DNA. The cationic emulsion also maintained the cellular responses seen with naked DNA at the same doses.
