Jeffrey J. Landers

Pre-Clinical Evaluation of a Novel Nanoemulsion-Based Hepatitis B Mucosal Vaccine

Background Hepatitis B virus infection remains an important global health concern despite the availability of safe and effective prophylactic vaccines. Limitations to these vaccines include requirement for refrigeration and three immunizations thereby restricting use in the developing world. A new nasal hepatitis B vaccine composed of recombinant hepatitis B surface antigen (HBsAg) in a novel nanoemulsion (NE) adjuvant (HBsAg-NE) could be effective with fewer administrations. Methodology and Principal Findings Physical characterization indicated that HBsAg-NE consists of uniform lipid droplets (349+/−17 nm) associated with HBsAg through electrostatic and hydrophobic interactions. Immunogenicity of HBsAg-NE vaccine was evaluated in mice, rats and guinea pigs. Animals immunized intranasally developed robust and sustained systemic IgG, mucosal IgA and strong antigen-specific cellular immune responses. Serum IgG reached ≥106 titers and was comparable to intramuscular vaccination with alum-adjuvanted vaccine (HBsAg-Alu). Normalization showed that HBsAg-NE vaccination correlates with a protective immunity equivalent or greater than 1000 IU/ml. Th1 polarized immune response was indicated by IFN-γ and TNF-α cytokine production and elevated levels of IgG2 subclass of HBsAg-specific antibodies. The vaccine retains full immunogenicity for a year at 4°C, 6 months at 25°C and 6 weeks at 40°C. Comprehensive pre-clinical toxicology evaluation demonstrated that HBsAg-NE vaccine is safe and well tolerated in multiple animal models. Conclusions Our results suggest that needle-free nasal immunization with HBsAg-NE could be a safe and effective hepatitis B vaccine, or provide an alternative booster administration for the parenteral hepatitis B vaccines. This vaccine induces a Th1 associated cellular immunity and also may provide therapeutic benefit to patients with chronic hepatitis B infection who lack cellular immune responses to adequately control viral replication. Long-term stability of this vaccine formulation at elevated temperatures suggests a direct advantage in the field, since potential excursions from cold chain maintenance could be tolerated without a loss in therapeutic efficacy.

Prevention of Influenza Pneumonitis by Sialic Acid–Conjugated Dendritic Polymers

Influenza A viral infection begins by hemagglutinin glycoproteins on the viral envelope binding to cell membrane sialic acid (SA). Free SA monomers cannot block hemagglutinin adhesion in vivo because of toxicity. Polyvalent, generation 4 (G4) SA-conjugated polyamidoamine (PAMAM) dendrimer (G4-SA) was evaluated as a means of preventing adhesion of 3 influenza A subtypes (H1N1, H2N2, and H3N2). In hemagglutination-inhibition assays, G4-SA was found to inhibit all H3N2 and 3 of 5 H1N1 influenza subtype strains at concentrations 32-170 times lower than those of SA monomers. In contrast, G4-SA had no ability to inhibit hemagglutination with H2N2 subtypes or 2 of 5 H1N1 subtype strains. In vivo experiments showed that G4-SA completely prevented infection by a H3N2 subtype in a murine influenza pneumonitis model but was not effective in preventing pneumonitis caused by an H2N2 subtype. Polyvalent binding inhibitors have potential as antiviral therapeutics, but issues related to strain specificity must be resolved.

Mucosal immunization with a novel nanoemulsion-based recombinant anthrax protective antigen vaccine protects against Bacillus anthracis spore challenge.

ABSTRACT The currently available commercial human anthrax vaccine requires multiple injections for efficacy and has side effects due to its alum adjuvant. These factors limit its utility when immunizing exposed populations in emergent situations. We evaluated a novel mucosal adjuvant that consists of a nontoxic, water-in-oil nanoemulsion (NE). This material does not contain a proinflammatory component but penetrates mucosal surfaces to load antigens into dendritic cells. Mice and guinea pigs were intranasally immunized with recombinant Bacillus anthracis protective antigen (rPA) mixed in NE as an adjuvant. rPA-NE immunization was effective in inducing both serum anti-PA immunoglobulin G (IgG) and bronchial anti-PA IgA and IgG antibodies after either one or two mucosal administrations. Serum anti-PA IgG2a and IgG2b antibodies and PA-specific cytokine induction after immunization indicate a Th1-polarized immune response. rPA-NE immunization also produced high titers of lethal-toxin-neutralizing serum antibodies in both mice and guinea pigs. Guinea pigs nasally immunized with rPA-NE vaccine were protected against an intradermal challenge with ∼1,000 times the 50% lethal dose (∼1,000× LD50) of B. anthracis Ames strain spores (1.38 × 103 spores), which killed control animals within 96 h. Nasal immunization also resulted in 70% and 40% survival rates against intranasal challenge with 10× LD50 and 100× LD50 (1.2 × 106 and 1.2 × 107) Ames strain spores. Our results indicate that NE can effectively adjuvant rPA for intranasal immunization. This potentially could lead to a needle-free anthrax vaccine requiring fewer doses and having fewer side effects than the currently available human vaccine.

Nasal Immunization with a Recombinant HIV gp120 and Nanoemulsion Adjuvant Produces Th1 Polarized Responses and Neutralizing Antibodies to Primary HIV Type 1 Isolates

Epidemiological and experimental data suggest that both robust neutralizing antibodies and potent cellular responses play important roles in controlling primary HIV-1 infection. In this study we have investigated the induction of systemic and mucosal immune responses to HIV gp120 monomer immunogen administered intranasally in a novel, oil-in-water nanoemulsion (NE) adjuvant. Mice and guinea pigs intranasally immunized by the application of recombinant HIV gp120 antigen mixed in NE demonstrated robust serum anti-gp120 IgG, as well as bronchial, vaginal, and serum anti-gp120 IgA in mice. The serum of these animals demonstrated antibodies that cross-reacted with heterologous serotypes of gp120 and had significant neutralizing activity against two clade-B laboratory strains of HIV (HIVBaL and HIVSF162) and five primary HIV-1 isolates. The analysis of gp120-specific CTL proliferation, INF-gamma induction, and prevalence of anti-gp120 IgG2 subclass antibodies indicated that nasal vaccination in NE also induced systemic, Th1-polarized cellular immune responses. This study suggests that NE should be evaluated as a mucosal adjuvant for multivalent HIV vaccines.

Development of immune response that protects mice from viral pneumonitis after a single intranasal immunization with influenza A virus and nanoemulsion.

Nanoemulsion, a water-in-oil formulation stabilized by small amounts of surfactant, is non-toxic to mucous membranes and produces biocidal activity against enveloped viruses. We evaluated nanoemulsion as an adjuvant for mucosal influenza vaccines. Mice (C3H/HeNHsd strain) were vaccinated intranasally with 5 x 10(5) plaque forming units (pfu) of influenza A virus (Ann Arbor/6/60 strain) and a nanoemulsion mixture. The mice were challenged on day 21 after immunization with an intranasal lethal dose of 2 x 10(5) pfu of virus. Animals vaccinated with the influenza A/nanoemulsion mixture were completely protected against infection, while animals vaccinated with either formaldehyde-killed virus or nanoemulsion alone developed viral pneumonitis and died by day 6 after the challenge. Mice vaccinated with virus/nanoemulsion mixture had rapid cytokine responses followed by high levels of specific anti-influenza immunoglobulin G (IgG) and immunoglobulin A (IgA) antibodies. Specificity of the immune response was confirmed by assessment of the proliferation and cytokine production in splenocytes. This paper demonstrates that nanoemulsion can be employed as a non-toxic mucosal adjuvant for influenza virus vaccine.

The fungicidal activity of novel nanoemulsion (X8W60PC) against clinically important yeast and filamentous fungi.

Surfactant nanoemulsions are water in oil preparations that proved to have a broad spectrum biocidal activity against a variety of microorganisms including Gram-positive and Gram-negative bacteria, spores and enveloped viruses. These preparations are non-toxic to the skin, mucous membrane and gastrointestinal tissues at biocidal concentrations. In this study, 0.1% of the nanoemulsion designated X8W60PC has shown fungicidal activity against yeast including Candida albicans and C. tropicalis in 15 minutes. C. tropicalis was more sensitive than C. albicans, which required a longer time or a higher concentration of the nanoemulsion to achieve killing. Neutral to slightly alkaline pH was more effective in killing the yeast cells than acidic pH. Using the minimum inhibitory concentration assay, 0.08% of the nanoemulsion was inhibitory to C. albicans, and parapsilosis and filamentous fungi including Microsporum gypseum,Trichophyton mentagrophytes,Trichophyton rubrum,Aspergillus fumigatus andFusarium oxysporum.None of the individual ingredients was as effective a fungicidal as the nanoemulsion at equivalent concentration. This shows that the nanoemulsion structure is an important factor in the anti-fungal activity. The X8W60PC has great potential as a topical anti-fungal agent and further investigation into the mechanism of fungicidal action is warranted.

A novel, killed-virus nasal vaccinia virus vaccine.

ABSTRACT Live-virus vaccines for smallpox are effective but have risks that are no longer acceptable for routine use in populations at minimal risk of infection. We have developed a mucosal, killed-vaccinia virus (VV) vaccine based on antimicrobial nanoemulsion (NE) of soybean oil and detergent. Incubation of VV with 10% NE for at least 60 min causes the complete disruption and inactivation of VV. Simple mixtures of NE and VV (Western Reserve serotype) (VV/NE) applied to the nares of mice resulted in both systemic and mucosal anti-VV immunity, virus-neutralizing antibodies, and Th1-biased cellular responses. Nasal vaccination with VV/NE vaccine produced protection against lethal infection equal to vaccination by scarification, with 100% survival after challenge with 77 times the 50% lethal dose of live VV. However, animals protected with VV/NE immunization did after virus challenge have clinical symptoms more extensive than animals vaccinated by scarification. VV/NE-based vaccines are highly immunogenic and induce protective mucosal and systemic immunity without the need for an inflammatory adjuvant or infection with live virus.

Nanoemulsion mucosal adjuvant uniquely activates cytokine production by nasal ciliated epithelium and induces dendritic cell trafficking

While the nasal mucosa is a potentially useful site for human immunization, toxin‐based nasal adjuvants are generally unsafe and less effective in humans. Safe mucosal adjuvants that activate protective immunity via mucosal administration are highly dependent on barrier antigen sampling by epithelial and DCs. Here, we demonstrate that protein antigens formulated in unique oil‐in‐water nanoemulsions (NEs) result in distinctive transcellular antigen uptake in ciliated nasal epithelial cells, leading to delivery into nasal associated lymphoid tissue. NE formulation also enhances MHC class II expression in epithelial cells and DC activation/trafficking to regional lymphoid tissues in mice. These materials appear to induce local epithelial cell apoptosis and heterogeneous cytokine production by mucosal epithelial cells and mixed nasal tissues, including G‐CSF, GM‐CSF, IL‐1a, IL‐1b, IL‐5, IL‐6, IL‐12, IP‐10, KC, MIP‐1a, TGF‐β, and TSLP. This is the first observation of a nasal adjuvant that activates calreticulin‐associated apoptosis of ciliated nasal epithelial cells to generate broad cytokine/chemokine responses in mucosal tissue.

Migrating Human Neutrophils Exhibit Dynamic Spatiotemporal Variation in Membrane Lipid Organization

Highly ordered sphingolipid-enriched lipid raft microdomains (LRMs) within plasma membranes purportedly function as specialized signaling platforms. Leukocyte migration is believed to entail LRM redistribution, but progress in studying LRMs in situ during cell movement has been limited. By using an improved method for imaging the spectral shift of the environmentally sensitive probe, laurdan (expressed as a generalized polarization function), the plasma membrane order (i.e., tight packing of membrane bilayer lipids) of human polymorphonuclear neutrophils (PMNs) was mapped in real time during migration. Morphologically polarized PMNs exhibited prominent LRM clusters at the uropod, where in every instance membrane order was found to oscillate with mean periodicities of 37.0 ± 1.46 and 149.9 ± 9.0 seconds (P < 0.01). LRM aggregates were also demonstrated in punctate and clustered distributions of nonpolarized cells and transiently at the lamellipodia of polarized PMNs. Cellular polarization was not accompanied by an overall increase in membrane order. LRM disorganization with methyl-β-cyclodextrin had small negative effects on cell velocity, but it abrogated directionally biased migration toward chemotactic gradients of FMLP or leukotriene B(4). LRMs disruption also caused redistribution of Rac 1/2 GTPase and GM3 ganglioside away from the lamellipodium, as well as extension of multiple pseudopods simultaneously or in rapid succession, rather than formation of a defined leading edge. Thus, we demonstrate that the plasma membrane order of migrating PMNs changes dynamically, with prominent oscillations consistently seen at the uropod. These findings solidify the existence of rapidly reorganizing LRMs in situ and support a role for LRMs in chemotaxin responsiveness.

Nanoemulsion adjuvant–driven redirection of TH2 immunity inhibits allergic reactions in murine models of peanut allergy

Background: Immunotherapy for food allergies involves progressive increased exposures to food that result in desensitization to food allergens in some subjects but not tolerance to the food. Therefore new approaches to suppress allergic immunity to food are necessary. Previously, we demonstrated that intranasal immunization with a nanoemulsion (NE) adjuvant induces robust mucosal antibody and TH17‐polarized immunity, as well as systemic TH1‐biased cellular immunity with suppression of pre‐existing TH2‐biased immunity. Objective: We hypothesized that immunization with food in conjunction with the nanoemulsion adjuvant could lead to modulation of allergic reactions in food allergy by altering pre‐existing allergic immunity and enhancing mucosal immunity. Methods: Mice were sensitized to peanut with aluminum hydroxide or cholera toxin. The animals were then administered 3 monthly intranasal immunizations with peanut in the nanoemulsion adjuvant or saline. Mice were then challenged with peanut to examine allergen reactivity. Results: The NE intranasal immunizations resulted in marked decreases in TH2 cytokine, IgG1, and IgE levels, whereas TH1 and mucosal TH17 immune responses were increased. After allergen challenge, these mice showed significant reductions in allergic hypersensitivity. Additionally, the NE immunizations significantly increased antigen‐specific IL‐10 production and regulatory T‐cell counts, and the protection induced by NE was dependent in part on IL‐10. Control animals immunized with intranasal peanut in saline had no modulation of their allergic response. Conclusions: NE adjuvant–mediated induction of mucosal TH17 and systemic TH1‐biased immunity can suppress TH2‐mediated allergy through multiple mechanisms and protect against anaphylaxis. These results suggest the potential therapeutic utility of this approach in the setting of food allergy.