Biomedical subjects

Gregory M Glenn

Publications and source records attributed to Gregory M Glenn.

14 recordsLinked to original sources

PubMed2006

GM1 binding-deficient exotoxin is a potent noninflammatory broad spectrum intradermal immunoadjuvant.

Intradermal (i.d.) immunization is a promising route of vaccine administration. Suitable i.d. adjuvants are important to increase vaccine efficacy in poorly responding populations such as the elderly or for dose-sparing strategies in the face of vaccine shortages. Bacterial exotoxins, such as Escherichia coli heat-labile enterotoxin (LT), exert strong immunostimulatory effects through binding to monosialoganglioside (GM1) cell surface receptors; however, injection is hampered by local inflammation. We demonstrate that the injection of LT formulations deficient in GM1 binding by mutation (LT(G33D)) or in vitro ligand coupling does not cause localized edema and inflammation in mice, yet these formulations retain potent adjuvant activity by enhancing functional Ab and cellular immune responses to coadministered Ags. Complete protection against in vivo lethal tetanus toxin challenge and the induction of Ag-specific CTL responses capable of killing target cells in vivo indicated in vivo efficacy of the induced immune responses. LT(G33D) proved superior to standard alum adjuvant regarding the magnitude and breadth of the induced immune responses. Immunizations in complex ganglioside knockout mice revealed a GM1-independent pathway of LT adjuvanticity. Immunostimulation by i.d. LT(G33D) is explained by its ability to induce migration of activated APCs to the proximal draining lymph nodes. LT(G33D) is a promising candidate adjuvant for human trials of parenteral vaccines in general and for current i.d. vaccine development in particular.

Adjuvants, Immunologic↗

PubMed2006

Permeability of starch gel matrices and select films to solvent vapors.

Volatile agrochemicals such as 2-heptanone have potential in safely and effectively controlling important agricultural pests provided that they are properly delivered. The present study reports the permeability of starch gel matrices and various coatings, some of which are agricultural-based, that could be used in controlled release devices. Low-density, microcellular starch foam was made from wheat, Dent corn, and high amylose corn starches. The foam density ranged from 0.14 to 0.34 g/cm3, the pore volume ranged from 74 to 89%, and the loading capacity ranged from 2.3 to 7.2 times the foam weight. The compressive properties of the foam were not markedly affected by saturating the pore volume with silicone oil. The vapor transmission rate (VTR) and vapor permeability (VP) were measured in dry, porous starch foam and silicone-saturated starch gels. VTR values were highest in foam samples containing solvents with high vapor pressures. Silicone oil-saturated gels had lower VTR and VP values as compared to the dry foam. However, the silicone oil gel did not markedly reduce the VP for 2-heptanone and an additional vapor barrier or coating was needed to adequately reduce the evaporation rate. The VP of films of beeswax, paraffin, ethylene vinyl alcohol, a fruit film, and a laminate comprised of beeswax and fruit film was measured. The fruit film had a relatively high VP for polar solvents and a very low VP for nonpolar solvents. The laminate film provided a low VP for polar and nonpolar solvents. Perforating the fruit film portion of the laminate provided a method of attaining the target flux rate of 2-heptanone. The results demonstrate that the vapor flux rate of biologically active solvents can be controlled using agricultural materials.

Amylose↗

PubMed2005

Improved immune responses to influenza vaccination in the elderly using an immunostimulant patch.

The elderly have greater morbidity and mortality due to influenza, and respond poorly to influenza vaccination compared to younger adults. This study was designed to determine if the adjuvant heat-labile enterotoxin from Escherichia coli (LT), administered as an immunostimulant (IS) patch on the skin with influenza vaccination, improves influenza immune responses in the elderly. Three weeks following vaccination, hemagglutination inhibition (HAI) responses in LT IS patch recipients showed improvement over those of elderly receiving vaccine alone, as demonstrated by significance or trends in fold rise [A/Panama (P = 0.004), A/New Caledonia (P = 0.09)], seroconversion [A/New Caledonia (63% versus 40%, P = 0.01), A/Panama (54% versus 36%, P = 0.08)] and seroprotection [26%, 20% and 16% greater for the patch group for A/New Caledonia, A/Panama and B/Shandong strains, respectively]. The data suggest that an LT IS patch may further enhance influenza vaccine immune responses in the elderly.

Adjuvants, Immunologic↗

PubMed2004

Dose sparing with intradermal injection of influenza vaccine.

BACKGROUND: The loss of half the U.S. supply of influenza vaccine due to contamination has created a critical shortage. Dose-sparing strategies that use intradermal delivery of vaccines may be one approach to consider. METHODS: We conducted a randomized, open-label trial outside the influenza season in 100 healthy adults 18 to 40 years of age to compare the immunogenicity and safety of intradermal immunization with influenza vaccine with standard intramuscular immunization. Subjects were randomly assigned to receive either a single intramuscular dose of 0.5 ml of trivalent influenza vaccine, containing at least 15 microg of hemagglutinin per strain, by means of a prefilled syringe or a single intradermal dose of 0.1 ml, containing at least 3 microg of hemagglutinin per strain, by means of a fine-gauge needle; both injections were in the deltoid region. Changes in the hemagglutination-inhibition (HAI) antibody titer were assessed by comparing geometric mean titers and fold increases relative to baseline values and by comparing changes in the seroconversion and seroprotection rates. Local and systemic adverse events were assessed after both types of vaccination. RESULTS: Subjects who received an intradermal injection with one fifth the standard dose of influenza vaccine had increases in the geometric mean HAI titer by a factor of 15.2 for the H1N1 strain in the vaccine, 19.0 for the H3N2 strain, and 12.4 for the B strain on day 21, as compared with respective increases by a factor of 14.9, 7.1, and 15.3 for the intramuscular injection of the standard dose. Seroconversion and seroprotection rates were similar in the two groups on day 21, ranging from 66 to 82 percent and 84 to 100 percent, respectively. Local reactions were significantly more frequent among recipients of intradermal injections than among recipients of intramuscular injections, but such reactions were mild and transient. CONCLUSIONS: In this study of young adults, intradermal administration of one fifth the standard intramuscular dose of an influenza vaccine elicited immunogenicity that was similar to or better than that elicited by intramuscular injection. Intradermal administration could be used to expand the supplies of influenza vaccine, but further studies are needed before this strategy can be recommended for routine use.

Adolescent↗

PubMed2004

Induction of protective immunity against lethal anthrax challenge with a patch.

BACKGROUND: Transcutaneous immunization (TCI) is a needle-free technique that delivers antigens and adjuvants to potent epidermal immune cells. To address critical unmet needs in biodefense against anthrax, we have designed a novel vaccine delivery system using a dry adhesive patch that simplifies administration and improves tolerability of a subunit anthrax vaccine. METHODS: Mice and rabbits were vaccinated with recombinant protective antigen of Bacillus anthracis and the heat-labile toxin of Escherichia coli. Serologic changes, levels of toxin-neutralizing antibodies (TNAs), and pulmonary and nodal responses were monitored in the mice. A lethal aerosolized B. anthracis challenge model was used in A/J mice, to demonstrate efficacy. RESULTS: The level of systemic immunity and protection induced by TCI was comparable to that induced by intramuscular vaccination, and peak immunity could be achieved with only 2 doses. The addition of adjuvant in the patch induced superior TNA levels, compared with injected vaccination. CONCLUSIONS: Anthrax vaccine patches stimulated robust and functional immune responses that protected against lethal challenge. Demonstration of responses in the lung suggests that a mechanism exists for protection against challenge with aerosolized anthrax spores. A formulated, pressure-sensitive, dry adhesive patch, which is stable and can be manufactured in large scale, elicited comparable immunoglobulin G and TNA responses, suggesting that an anthrax vaccine patch is feasible and should advance into clinical evaluation.

Adjuvants, Immunologic↗

PubMed2004

Needle-free skin patch vaccination method for anthrax.

Three immunizations of mice with recombinant protective antigen (rPA) by transcutaneous immunization (TCI) induced long-term neutralizing antibody titers that were superior to those obtained with aluminum-adsorbed rPA. In addition, rPA alone exhibited adjuvant activity for TCI. Forty-six weeks after completion of TCI, 100% protection was observed against lethal anthrax challenge.

Adjuvants, Immunologic↗

PubMed2004

Immunostimulant patch enhances immune responses to influenza virus vaccine in aged mice.

Improvement in the immune response to influenza virus vaccination in the elderly represents the primary unmet need in influenza virus vaccination. We have shown that topical application of immunostimulating (IS) patches containing heat-labile enterotoxin of Escherichia coli (LT) enhances immune responses to injected vaccines. We extend these findings and show that LT-IS patch application enhances the antibody responses to influenza virus vaccination in both young and aged mice. LT-IS patches markedly increased influenza virus-specific immunoglobulin G (IgG), hemagglutination inhibition antibody, mucosal antibody, and T-cell responses. The magnitude of the immune responses in aged mice receiving an LT-IS patch was equivalent to or greater than that of the immune responses in young mice given vaccine alone. These results suggest that addition of an LT-IS patch may compensate for the deficient immune function seen in the aged in response to influenza virus vaccination. Therefore, use of an LT-IS patch could be a new, safe, and simple immunization strategy that may significantly improve the outcome of influenza virus vaccination in the elderly.

Adjuvants, Immunologic↗

PubMed2004

Transcutaneous immunization induces mucosal CTLs and protective immunity by migration of primed skin dendritic cells.

Transcutaneous immunization (TCI), the application of vaccines on the skin, induces robust systemic and mucosal antibodies in animal models and in humans. The means by which mucosal immune responses to vaccine antigens are elicited by TCI has not been well characterized. We examined the effect of TCI with an HIV peptide vaccine on the induction of mucosal and systemic CTL responses and protective immunity against mucosal challenge with live virus in mice. Robust HIV-specific CTL responses in the spleen and in the gut mucosa were detected after TCI. The responses were dependent upon the addition of an adjuvant and resulted in protection against mucosal challenge with recombinant vaccinia virus encoding HIV gp160. Although it is clear that adjuvant-activated DCs migrated mainly to draining lymph nodes, coculture with specific T cells and flow cytometry studies with DCs isolated from Peyer's patches after TCI suggested that activated DCs carrying skin-derived antigen also migrated from the skin to immune-inductive sites in gut mucosa and presented antigen directly to resident lymphocytes. These results and previous clinical trial results support the observation that TCI is a safe and effective strategy for inducing strong mucosal antibody and CTL responses.

Administration, Cutaneous↗

PubMed2003

Histological structures of cooked rice grain.

Raw and cooked whole grain sections of milled, medium grain California rice were compared for gross histological and morphological features using fluorescence and scanning electron microscopy (SEM). Cooked and raw grains were compared and the differences were assessed by autofluorescence of the cell walls and correlating fluorescence to SEM images. Milled, raw grains contain fine cracks throughout the endosperm. Cooked grains have wider, more defined cracks, suggesting that they serve as channels for water migration into the grain during cooking. Water penetrates unequally into the grain during cooking: low water penetration produces dense regions with minimal starch gelatinization, and high water penetration produces large voided areas. The voids occur in the transverse orientation of the grain and are the main of cause grain expansion during cooking.

Fluorescence↗

PubMed2003

Transcutaneous immunization and immunostimulant strategies.

The skin provides an attractive immune environment for vaccine delivery and a safe and confined anatomic space for the use of potent adjuvants. It has been presumed that LCs as a class of dendritic cells should stimulate potent immune responses when activated by adjuvants, and this theory is beginning to be validated. Progress on simple pretreatment of the skin has led to well-developed, simple-to-use protocols that are not dissimilar from current protocols used to cleanse the skin before injection. Antigen and adjuvant formulation optimization has progressed, leading to phase 2 testing of the technology in formulated, manufacturable patches. Although delivery optimization and product testing is challenging, the major biologic observations underlying TCI and the IS patch have been established clearly in that large protein antigens have been delivered clinically, resulting in robust immune responses in a safe manner. During the next 5 years, the challenge will be to conduct a development program that leads to safe and effective vaccination in the context of specific applications.

Administration, Cutaneous↗

PubMed2003

Immunostimulant patch containing heat-labile enterotoxin from Escherichia coli enhances immune responses to injected influenza virus vaccine through activation of skin dendritic cells.

Vaccine strategies, such as influenza virus vaccination of the elderly, are highly effective at preventing disease but provide protection for only the responding portion of the vaccinees. Adjuvants improve the magnitude and rates of responses, but their potency must be attenuated to minimize side effects. Topical delivery of strong adjuvants such as heat-labile enterotoxin from Escherichia coli (LT) induces potent immune responses. We hypothesized that LT delivered alone in an immunostimulating (LT-IS) patch placed on the skin at the site of injection could augment the immune response to injected vaccines. This was based on the observation that topically applied LT induces migration of activated antigen-presenting cells (APCs) from the skin to the proximal draining lymph node (DLN), and that APCs loaded with antigen by injection in the same anatomical region also migrate to the same DLN. We observed that when influenza virus vaccine is injected and an LT-IS patch is placed to target the same DLN, the influenza virus antibody response is enhanced. Similarly, influenza virus-specific T cells isolated from the lungs show increased levels of gamma interferon and interleukin-4 production. An LT-IS patch placed near an injected vaccine also leads to increased levels of hemagglutination inhibition titers, enhanced mucosal immunoglobulin A responses, and enhanced antigen presentation. Although the mechanisms by which an LT-IS patch exerts its enhancing effects need further study, the enhanced immune responses, ability to safely use potent adjuvants, and simplicity of LT-IS patch application address an important unmet need and provide a new immune enhancement strategy.

Adjuvants, Immunologic↗

PubMed2003

Transcutaneous immunization and immunostimulant strategies: capitalizing on the immunocompetence of the skin.

The skin is an attractive target for vaccine delivery. Topical application of adjuvants results in potent immune responses and good safety profiles. Adjuvants can be coadministered in a patch with vaccine antigens (transcutaneous immunization) or similar delivery format, or administered separately with an injection or IS patch (Iomai), leading to enhanced immune responses. These observations have moved into the clinic, highlighting the likelihood that skin delivery of vaccines will play an important future role in vaccine applications.

Adjuvants, Immunologic↗

PubMed2002

Sorption and vapor transmission properties of uncompressed and compressed microcellular starch foam.

Microcellular starch foams (MCFs) are made by a solvent-exchange process and consist of a porous matrix with pores generally ranging from approximately 2 microm to submicrometer size. MCF may potentially be useful as a slow-release agent for volatile compounds because of its ability to sorb chemicals from the atmosphere and to absorb liquids into its porous structure, and because it can be compressed to form a starch plastic. MCF made of high-amylose corn and wheat starches was prepared with or without 2% (w/w) silicone oil (SO) or palmitic acid (PA). The MCF was loaded with 1% of various volatile compounds with vapor pressures ranging from 0.02 to 28 mm. The MCF depressed the vapor pressure from 0.37 to 37% compared to a control containing no MCF. Incorporating SO or PA in the matrix of the MCF had little effect on sorption of volatiles. Compressing MCF at 1.4, 6.9, and 69 MPa made a starch plastic with varying porosity. The vapor transmission rate of various volatile compounds through MCF was positively correlated to the vapor pressure of the test compound but was inversely proportional to the compression force used to form the starch plastic. The results indicate that uncompressed and compressed MCFs could be effective slow-release agents for a variety of volatile compounds, especially if used together.

Adsorption↗

PubMed2002

Safety and immunogenicity of a prototype enterotoxigenic Escherichia coli vaccine administered transcutaneously.

Transcutaneous immunization (TCI) is a new method for vaccine delivery that has been shown to induce immunity relevant to enteric disease vaccines. We evaluated the clinical safety and immunogenicity of a recombinant subunit vaccine against enterotoxigenic Escherichia coli (ETEC) delivered by TCI. Adult volunteers received patches containing the recombinant ETEC colonization factor CS6, either with heat-labile enterotoxin (LT) or patches containing CS6 alone. The vaccine was administered at 0, 1, and 3 months, and serum antibodies and antibody-secreting cells (ASCs) were assessed. Among the 26 volunteers that completed the trial, there were no responses to CS6 in the absence of LT. In the groups receiving both CS6 and LT, 68 and 53% were found to have serum anti-CS6 immunoglobulin G (IgG) and IgA, respectively; 37 and 42% had IgG and IgA anti-CS6 ASCs. All of the volunteers receiving LT had anti-LT IgG, and 90% had serum anti-LT IgA; 79 and 37% had anti-LT IgG and IgA ASCs. Delayed-type hypersensitivity (DTH), suggesting T-cell responses, was seen in 14 of 19 volunteers receiving LT and CS6; no DTH was seen in subjects receiving CS6 alone. This study demonstrated that protein antigens delivered by a simple patch could induce significant systemic immune responses but only in the presence of an adjuvant such as LT. The data suggest that an ETEC vaccine for travelers delivered by a patch may be a viable approach worthy of further evaluation.

Administration, Cutaneous↗