Vaccine microarray patch self-administration: An innovative approach to improve pandemic and routine vaccination rates

The high-density microprojection array patch (HD-MAP) is a novel vaccine delivery system with potential for self-administered vaccination. HD-MAPs provide an alternative to needle and syringe (N&S) vaccination. Additional advantages could include reduced cold-chain requirements, reduced vaccine dose, reduced vaccine wastage, an alternative for needle phobic patients and elimination of needlestick injuries. The drivers and potential benefits of vaccination by self-administering HD-MAPs are high patient acceptance and preference, higher vaccination rates, speed of roll-out, cost-savings, and reduced sharps and environmental waste. The HD-MAP presents a unique approach in pandemic preparedness and routine vaccination of adults. It could alleviate strain on the healthcare workforce and allows vaccine administration by minimally-trained workers, guardian or subjects themselves. Self-vaccination using HD-MAPs could occur in vaccination hubs with supervision, at home after purchasing at the pharmacy, or direct distribution to in-home settings. As a result, it has the potential to increase vaccine coverage and expand the reach of vaccines, while also reducing labor costs associated with vaccination. Key challenges remain around shifting the paradigm from medical professionals administrating vaccines using N&S to a future of self-administration using HD-MAPs. Greater awareness of HD-MAP technology and improving our understanding of the implementation processes required for adopting this technology, are critical factors underpinning HD-MAP uptake by the public.

Evaluation of the self-administration potential of high-density microarray patches to human skin: A preliminary study

The high-density microneedle array patch (HD-MAP) is a novel vaccine delivery system with potential for self-administered vaccination. In this study, Vaxxas HD-MAPs were applied by both a trained user and self-administered with application sites compared to determine the response of skin and the level of engagement of the HD-MAP with human skin. Twenty healthy participants were enrolled, and the response of skin including erythema was observed at all application sites and no difference was found between trained user or self-administered applications. The majority of participants (70%) preferred the deltoid upper arm application site for applying HD-MAPs. Fluorescent dermatoscope images confirmed HD-MAPs engaged the skin surface and scanning electron microscopy (SEM) image analysis exhibited similar delivery characteristics for the upper arm and forearm sites when applied by either a trained user or self-administered. This study showed that noninvasive methods including dermatoscopy and SEM image analysis were able to estimate the engagement of HD-MAPs with human skin. HD-MAP self-vaccination technology has a unique proposition in pandemic preparedness by alleviating the need for health-care workers to administer vaccines, however greater awareness and understanding of the potential of this technology is required.

Functional characterization of the collagen-binding protein DIP2093 and its influence on host-pathogen interaction and arthritogenic potential of Corynebacterium diphtheriae

Corynebacterium diphtheriae is typically recognized as the a etiological agent of diphtheria, a toxaemic infection of the respiratory tract; however, both non-toxigenic and toxigenic strains are increasingly isolated from cases of invasive infections. The molecular mechanisms responsible for bacterial colonization and dissemination to host tissues remain only partially understood. In this report, we investigated the role of DIP2093, described as a putative adhesin of the serine-aspartate repeat (Sdr) protein family in host-pathogen interactions of C. diphtheriae wild-type strain NCTC13129. Compared to the parental strain, a DIP2093 mutant RN generated in this study was attenuated in its ability to bind to type I collagen, to adhere to and invade epithelial cells, as well as to survive within macrophages. Furthermore, DIP2093 mutant strain RN had a less detrimental impact on the viability of Caenorhabditis elegans as well as in the clinical severity of arthritis in mice. In conclusion, DIP2093 functions as a microbial surface component recognizing adhesive matrix molecules, and may be included among the factors that contribute to the pathogenicity of C. diphtheriae strains, independently of toxin production.

Pathogenic properties of a Corynebacterium diphtheriae strain isolated from a case of osteomyelitis

Corynebacterium diphtheriae is typically recognized as a colonizer of the upper respiratory tract (respiratory diphtheria) and the skin (cutaneous diphtheria). However, different strains of Corynebacteriumdiphtheriae can also cause invasive infections. In this study, the characterization of a non-toxigenic Corynebacteriumdiphtheriae strain (designated BR-INCA5015) isolated from osteomyelitis in the frontal bone of a patient with adenoid cystic carcinoma was performed. Pathogenic properties of the strain BR-INCA5015 were tested in a Caenorhabditis elegans survival assay showing strong colonization and killing by this strain. Survival rates of 3.8±2.7 %, 33.6±7.3 % and 0 % were observed for strains ATCC 27010T, ATCC 27012 and BR-INCA5015, respectively, at day 7. BR-INCA5015 was able to colonize epithelial cells, showing elevated capacity to adhere to and survive within HeLa cells compared to other Corynebacteriumdiphtheriae isolates. Intracellular survival in macrophages (THP-1 and RAW 264.7) was significantly higher compared to control strains ATCC 27010T (non-toxigenic) and ATCC 27012 (toxigenic). Furthermore, the ability of BR-INCA5015 to induce osteomyelitis was confirmed by in vivo assay using Swiss Webster mice.

Corynebacterium ulcerans, an emerging human pathogen

While formerly known infections of Corynebacterium ulcerans are rare and mainly associated with contact to infected cattle, C. ulcerans has become an emerging pathogen today. In Western Europe, cases of respiratory diphtheria caused by C. ulcerans have been reported more often than infections by Corynebacterium diphtheria, while systemic infections are also increasingly reported. Little is known about factors that contribute to host colonization and virulence of this zoonotic pathogen. Research in this field has received new impetus by the publication of several C. ulcerans genome sequences in the past years. This review gives a comprehensive overview of the basic knowledge of C. ulcerans, as well as the recent advances made in the analysis of putative virulence factors.

The killing of macrophages by Corynebacterium ulcerans

Corynebacterium ulcerans is an emerging pathogen transmitted by a zoonotic pathway with a very broad host spectrum to humans. Despite rising numbers of infections and potentially fatal outcomes, data on the molecular basis of pathogenicity are scarce. In this study, the interaction of 2 C. ulcerans isolates - one from an asymptomatic dog, one from a fatal case of human infection - with human macrophages was investigated. C. ulcerans strains were able to survive in macrophages for at least 20 hours. Uptake led to delay of phagolysosome maturation and detrimental effects on the macrophages as deduced from cytotoxicity measurements and FACS analyses. The data presented here indicate a high infectious potential of this emerging pathogen.

Caenorhabditis elegans star formation and negative chemotaxis induced by infection with corynebacteria

Caenorhabditis elegans is one of the major model systems in biology based on advantageous properties such as short life span, transparency, genetic tractability and ease of culture using an Escherichia coli diet. In its natural habitat, compost and rotting plant material, this nematode lives on bacteria. However, C. elegans is a predator of bacteria, but can also be infected by nematopathogenic coryneform bacteria such Microbacterium and Leucobacter species, which display intriguing and diverse modes of pathogenicity. Depending on the nematode pathogen, aggregates of worms, termed worm-stars, can be formed, or severe rectal swelling, so-called Dar formation, can be induced. Using the human and animal pathogens Corynebacterium diphtheriae and Corynebacterium ulcerans as well as the non-pathogenic species Corynebacterium glutamicum, we show that these coryneform bacteria can also induce star formation slowly in worms, as well as a severe tail-swelling phenotype. While C. glutamicum had a significant, but minor influence on survival of C. elegans, nematodes were killed after infection with C. diphtheriae and C. ulcerans. The two pathogenic species were avoided by the nematodes and induced aversive learning in C. elegans.

Colonization of human epithelial cell lines by Corynebacterium ulcerans from human and animal sources

Corynebacterium ulcerans is an emerging pathogen transmitted by a zoonotic pathway to humans. Despite rising numbers of infections and potentially fatal outcomes, data on the colonization of the human host are lacking up to now. In this study, adhesion of two C. ulcerans isolates to human epithelial cells, invasion of host cells and the function of two putative virulence factors with respect to these processes were investigated. C. ulcerans strains BR-AD22 and 809 were able to adhere to Detroit562 and HeLa cells, and invade these epithelial cell lines with a rate comparable to other pathogens as shown by scanning electron microscopy, fluorescence microscopy and replication assays. Infection led to detrimental effects on the cells as deduced from measurements of transepithelial resistance. Mutant strains of putative virulence factors phospholipase D and DIP0733 homologue CULC22_00609 generated in this study showed no influence on colonization under the experimental conditions tested. The data presented here indicate a high infectious potential of this emerging pathogen.

Characterization of DIP0733, a multi-functional virulence factor of Corynebacterium diphtheriae

Corynebacterium diphtheriae is typically recognized as an extracellular pathogen. However, a number of studies revealed its ability to invade epithelial cells, indicating a more complex pathogen-host interaction. The molecular mechanisms controlling and facilitating internalization of Cor. diphtheriae are poorly understood. In this study, we investigated the role of DIP0733 as virulence factor to elucidate how it contributes to the process of pathogen-host cell interaction. Based on in vitro experiments, it was suggested recently that the DIP0733 protein might be involved in adhesion, invasion of epithelial cells and induction of apoptosis. A corresponding Cor. diphtheriae mutant strain generated in this study was attenuated in its ability to colonize and kill the host in a Caenorhabditis elegans infection model system. Furthermore, the mutant showed an altered adhesion pattern and a drastically reduced ability to adhere and invade epithelial cells. Subsequent experiments showed an influence of DIP0733 on binding of Cor. diphtheriae to extracellular matrix proteins such as collagen and fibronectin. Furthermore, based on its fibrinogen-binding activity, DIP0733 may play a role in avoiding recognition of Cor. diphtheriae by the immune system. In summary, our findings support the idea that DIP0733 is a multi-functional virulence factor of Cor. diphtheriae.

Ca/calmodulin kinase II differentially modulates potassium currents

BACKGROUND

Potassium currents contribute to action potential duration (APD) and arrhythmogenesis. In heart failure, Ca/calmodulin-dependent protein kinase II (CaMKII) is upregulated and can alter ion channel regulation and expression.

METHODS AND RESULTS

We examine the influence of overexpressing cytoplasmic CaMKIIdelta(C), both acutely in rabbit ventricular myocytes (24-hour adenoviral gene transfer) and chronically in CaMKIIdelta(C)-transgenic mice, on transient outward potassium current (I(to)), and inward rectifying current (I(K1)). Acute and chronic CaMKII overexpression increases I(to,slow) amplitude and expression of the underlying channel protein K(V)1.4. Chronic but not acute CaMKII overexpression causes downregulation of I(to,fast), as well as K(V)4.2 and KChIP2, suggesting that K(V)1.4 expression responds faster and oppositely to K(V)4.2 on CaMKII activation. These amplitude changes were not reversed by CaMKII inhibition, consistent with CaMKII-dependent regulation of channel expression and/or trafficking. CaMKII (acute and chronic) greatly accelerated recovery from inactivation for both I(to) components, but these effects were acutely reversed by AIP (CaMKII inhibitor), suggesting that CaMKII activity directly accelerates I(to) recovery. Expression levels of I(K1) and Kir2.1 mRNA were downregulated by CaMKII overexpression. CaMKII acutely increased I(K1), based on inhibition by AIP (in both models). CaMKII overexpression in mouse prolonged APD (consistent with reduced I(to,fast) and I(K1)), whereas CaMKII overexpression in rabbit shortened APD (consistent with enhanced I(K1) and I(to,slow) and faster I(to) recovery). Computational models allowed discrimination of contributions of different channel effects on APD.

CONCLUSIONS

CaMKII has both acute regulatory effects and chronic expression level effects on I(to) and I(K1) with complex consequences on APD.

Laser conditioning of LaF(3)/MgF(2) dielectric coatings at 248 nm

Highly reflective LaF(3)/MgF(2) systems for a wavelength of 248 nm on MgF(2) and crystalline quartz substrates were investigated. The influence of laser conditioning on damage threshold and absorptance was remarkable in those coatings that had a high initial absorptance. Monitoring with a laser calorimeter revealed the conditioning effect to be a function of the irradiation dose rather than of energy density or pulse rate. Furthermore, x-ray photoelectron spectroscopy and transmission electron microscopy investigations showed that conditioning induces stoichiometric and structural changes in the multilayers, especially in near-surface sublayers, whereas scanning electron microscopy and atomic force microscopy investigations indicated that the surface remains unchanged.

Investigations on the rectal absorption of chloramphenicol in rabbits after tenside use

The rectal dose of 16 mg.kg-1 b.w. chloramphenicol (1) without additional tensides did not result in any detectable absorption of effective substance. In contrast, 0.04% of the N-lauroylleucine tenside allowed a rectal absorption having the same effect as that of an injection of the same quantities of effective substance. The tenside efficiency was not influenced by varied suppository masses (gelatine or Rosupol U, respectively), or by the pH value of the suppositories. Different particle sizes (less than 40 microns or greater than or equal to 40 up to less than 400 microns) of 1 did not change the absorption rate (AUC0-5h) significantly, but did change the plasma concentration-time profile considerably.

The protection of insulin against proteolytic processes after rectal application to normoglycemic rabbits

In order to improve the bioavailability of insulin after rectal application to rabbits, the influence of surface-active amino acid-fatty acid condensate on absorption and, the effects of a protease inhibitor (aprotinine), of a disinfectant (methyl-hydroxybenzoate) and of chemotherapeutics (chloramphenicol, ambazone and metronidazole) were investigated. Only the application of methylhydroxybenzoate, ambazone and of metronidazole, which inhibit the anaerobic bacterial flora, improved bioavailability significantly. The examinations show that the proteolytic activity of the anaerobic bacterial flora causes the loss of the biological activity of peptides in the rectum.

[Scintigraphy of sustained-release agar-embedded insulin suppositories]

In earlier publications [1-3] we reported on the retardation and protective effect of insulin-agar-embeddings in triglyceride suppositories by in vitro and in vivo tests on rabbits. The discovered effects were visually followed by gammascintigraphic test of adequate rectally applied 131I-insulin-specimens in the rectum and thyroid gland and, in relation with the glucose lowering course, the liberation, distribution and bioavailability of the immobilized hormone was illustrated.

[The application of insulin-agar embedding in suppositories for controlled hormone liberation and dose lowering]

By embedding of insulin in agar a significant retardation as well as a protective effect for the hormone is obtained. As demonstrated on in vivo animal experiments, this embedding method in dependence on the insulin concentration and particle size of the polymeric matrix allows to prepare rectal insulin applications with remarkable depot effects. Alternatively in combination with resorption promoting tensides it permits to lower the administered hormone doses to a order of magnitude reaching those used for parenteral insulin applications.