Advances in oral vaccine delivery options

Vaccines have been one of the most far-reaching and important public health initiatives of the 20th century. Yet as we move into the 21st century, millions of people still die from vaccine-preventable diseases such as measles and tetanus, and complex diseases, such as malaria and HIV, for which we have no vaccines. New vaccines that can be administered orally, are stable at ambient temperature, and can be produced cheaply, have the potential to transform health policy and practice in both developed and developing countries. Although oral delivery is the preferred route of administration, it is inefficient for the delivery of ‘naked’ antigens. Delivery of a vaccine via the oral route in a sufficient dose to induce a protective immune response depends on overcoming the loss of antigen integrity that occurs during intestinal passage. Several strategies have been employed to prevent this loss of antigen(icity) and improve the delivery of vaccinogens by the oral route. These include live vectors, transgenic plants, and particulate formulations such as microparticles, liposomes, and virus-like particles. Although many of these systems have progressed to clinical trials, the most promising results are seen where strategies are combined. Prime-boost schedules and combined technologies are likely to be a critical component of future oral vaccination schedules. Further technological breakthroughs may also be required before strong protective immune responses can be consistently induced in humans. Nonetheless, the potential of future oral vaccination strategies is readily apparent.     

Characterization of Bacillus strains and hoax agents by protein profiling using automated microfluidic capillary electrophoresis

Purpose

In recent times, but especially since 2001, bioterrorism has been of increasing concern. In addition to the use of biological agents, including Bacillus anthracis (anthrax), there have been numerous hoax white powder “scares.” It is imperative to rapidly and accurately identify any suspicious powder as hazardous or hoax. Classical methods for identification typically rely on time-consuming cultivation or highly specific molecular tests which are limited if the agent is unknown. Faster and field portable methods for analysis of suspicious powders are urgently required.

Methods

Potential hoax agents, including Bacillus species and household powders, were analyzed using automated microfluidic capillary electrophoresis to determine if protein profiling can distinguish between, and identify, samples.

Results

Distinctive protein profiles were produced for Bacillus species, with the presence and/or absence of certain bands, aiding identification. In particular B. anthracis Sterne strain contained a distinctive doublet band above 100 kDa which was not present in any other Bacillus species or hoax agents examined. The majority of powders produced distinctive banding that could enable the identification of the sample while simultaneously ruling out B. anthracis with a high degree of confidence.

Conclusions

Results show automated microfluidic capillary electrophoresis can rapidly and reproducibly characterize Bacillus species and hoax agents based on protein profiles without the need for culture. Results were reproducible and there was enhanced resolution and rapidity compared to traditional protein profiling methods. Results show this technique is amenable to field use at a bioterrorism incident, thereby providing essential information to investigators regarding containment and treatment strategies.     

A Post-hoc Comparison of Paliperidone Palmitate to Oral Risperidone During Initiation of Long-acting Risperidone Injection in Patients with Acute Schizophrenia

Objective: First-month data of a 13-week acute schizophrenia study were used to compare paliperidone palmitate to oral risperidone during initiation of long-acting injectable risperidone.Design: Double-blind, randomized study.Setting: Outpatient or inpatient.Participants: Adults with established (≥1 year) schizophrenia. Those assigned to risperidone long-acting injectable (n=460) received 25mg on Days 8 and 22 with oral risperidone (l-6mg) supplementation for the first 28 days. The paliperidone palmitate group (n=453) received 150mg eq. on Day 1, l00mg eq. on Day 8, and oral placebo supplementation for the first 28 days.Measurements: Positive and Negative Syndrome Scale, Personal and Social Performance Scale, Clinical Global Impression-Severity score, and responder rate (percentage of patients with ≥30% reduction in PANSS total score). An analysis of covariance model estimated least-square mean differences between treatment groups. A post-hoc analysis of efficacy data for the period of interest, i.e., at the time points before and after the first 28 days, was conducted.Results: Positive and Negative Syndrome Scale, Personal and Social Performance Scale, Clinical global Impression-Severity scores showed similar efficacy between the treatment groups during the first weeks of treatment, corresponding to the risperidone long-acting injection initiation period. Mean Positive and Negative Syndrome Scale total score at baseline was 84.7 for paliperidone palmitate and 84.4 for oral risperidone, on Day 22 was 73.6 and 74.1, respectively, and on Day 36 was 71.8 and 72.8, respectively. Overall incidence of adverse events in the first 28 days was generally similar (45% for paliperidone palmitate vs. 35% for oral risperidone), except for injection site pain (4.6% vs. 0.7%). Similar active moiety plasma concentrations were obtained during this period.Conclusion: During the first month, paliperidone palmitate without oral supplementation has similar efficacy and safety to oral risperidone (during initiation of risperidone long-acting injectable) in acutely exacerbated schizophrenia.     

Relationship between cognitive domains, physical performance, and gait in elderly and demented subjects

Cognitive function declines with age, with studies linking decreases in cognitive function to increased fall risk. The association between declines in specific cognitive domains and the development of gait and physical performance deficits has not been established. The current cross-sectional study was designed to address these issues using well characterized control subjects (n = 50), and individuals with early stage dementia (n = 50) tightly matched for age, gender, and education. All participants received detailed cognitive assessments for global cognitive function, as well as for processing speed, verbal fluency, and executive function. Additionally, participants were administered single- and dual-task gait assessments (GAITRite) and Short Physical Performance Battery (SPPB) measures of physical performance (gait, balance, chair stands). Data show that all measures of cognitive function correlated significantly with measures of gait and physical performance when analyzed in all subjects or just subjects with dementia. However, data also reveal that measures of processing speed and verbal fluency correlated significantly with multiple aspects of motor performance in non-demented, control subjects, even when corrected for age. There was no correlation between global cognitive function and motor performance, and only limited relationship between executive function and motor performance in non-demented, control subjects. These studies reveal the complex interactions between cognitive function and gait/physical performance in the context of aging and dementia, and suggest that impairments in specific cognitive domains might undermine gait and physical performance and thus exacerbate fall risk in the elderly.     

Investigation of the mechanisms by which Listeria monocytogenes grows in porcine gallbladder bile

The food-borne pathogen Listeria monocytogenes is known to colonize the lumen of the gallbladder in infected mice and to grow rapidly in this environment (J. Hardy et al., Science 303:851-853, 2004). However, relatively little is known about the mechanisms utilized by the pathogen to survive and grow in this location. We utilized gallbladder bile (GB bile) isolated directly from porcine gallbladders as an ex vivo model of gallbladder growth. We demonstrate that GB bile is generally nontoxic for bacteria and can readily support growth of a variety of bacterial species including L. monocytogenes, Lactococcus lactis, Salmonella enterica serovar Typhimurium, and Escherichia coli. Significantly, L. monocytogenes grew at the same rate as the nonpathogenic species Listeria innocua, indicating that the pathogen does not possess specialized mechanisms that enable growth in this environment. However, when we reduced the pH of GB bile to pH 5.5 in order to mimic the release of bile within the small intestine, the toxicity of GB bile increased significantly and specific resistance mechanisms (Sigma B, BSH, and BilE) were essential for survival of the pathogen under these conditions. In order to identify genetic loci that are necessary for growth of L. monocytogenes in the gallbladder, a mariner transposon bank was created and screened for mutants unable to replicate in GB bile. This led to the identification of mutants in six loci, including genes encoding enzymes involved in purine metabolism, amino acid biosynthesis, and biotin uptake. Although GB bile does not represent a significant impediment to bacterial growth, specific metabolic processes are required by L. monocytogenes in order to grow in this environment.     

Applications of animal models of infectious arthritis in drug discovery: a focus on alphaviral disease

Animal models, which mimic human disease, are invaluable tools for understanding the mechanisms of disease pathogenesis and development of treatment strategies. In particular, animal models play important roles in the area of infectious arthritis. Alphaviruses, including Ross River virus (RRV), o'nyong-nyong virus, chikungunya virus (CHIKV), mayaro virus, Semliki Forest virus and sindbis virus, are globally distributed and cause transient illness characterized by fever, rash, myalgia, arthralgia and arthritis in humans. Severe forms of the disease result in chronic incapacitating arthralgia and arthritis. The mechanisms of how these viruses cause musculoskeletal disease are ill defined. In recent years, the use of a mouse model for RRV-induced disease has assisted in unraveling the pathobiology of infection and in discovering novel drugs to ameliorate disease. RRV as an infection model has the potential to provide key insights into such disease processes, particularly as many viruses, other than alphaviruses, are known to cause infectious arthritides. The emergence and outbreak of CHIKV in many parts of the world has necessitated the need to develop animal models of CHIKV disease. The development of non-human primate models of CHIKV disease has given insights into viral tropism and disease pathogenesis and facilitated the development of new treatment strategies. This review highlights the application of animal models of alphaviral diseases in the fundamental understanding of the mechanisms that contribute to disease and for defining the role that the immune response may have on disease pathogenesis, with the view of providing the foundation for new treatments.     

Whole‐genome sequencing and antigenic analysis of the first equine influenza virus identified in Turkey

Background

In 2013, there was an outbreak of acute respiratory disease in racehorses in Turkey. The clinical signs were consistent with equine influenza (EI).

Objective

The aim was to confirm the cause of the outbreak and characterise the causal virus.

Methods

A pan‐reactive influenza type A real‐time RT‐PCR and a rapid antigen detection kit were used for confirmatory diagnosis of equine influenza virus (EIV). Immunological susceptibility to EIV was examined using single radial haemolysis and ELISA. Antigenic characterisation was completed by haemagglutinin inhibition using a panel of specific ferret antisera. Genetic characterisation was achieved by whole‐genome sequencing using segment‐specific primers with M13 tags.

Results

A H3N8 EIV of the Florida clade 2 sublineage (FC2) was confirmed as the causal agent. The index cases were unvaccinated and immunologically susceptible. Phylogenetic analysis of the HA1 and NA genes demonstrated that A/equine/Ankara/1/2013 clustered with the FC2 strains circulating in Europe. Antigenic characterisation confirmed the FC2 classification and demonstrated the absence of significant drift. Whole‐genome sequencing indicated that A/equine/Ankara/1/2013 is most closely related to the viruses described as the 179 group based on the substitution I179V in HA1, for example A/equine/East Renfrewshire/2/2011, A/equine/Cambremer/1/2012 and A/equine/Saone et Loire/1/2015. The greatest diversity was observed in the NS1 segment and the polymerase complex.

Conclusions

The first recorded outbreak of EI in Turkey was caused by an FC2 virus closely related to viruses circulating in Europe. Antigenic and genetic characterisation gave no indication that the current OIE recommendations for EI vaccine composition require modification.     

Bacterial bile salt hydrolase in host metabolism: Potential for influencing gastrointestinal microbe-host crosstalk

Controlled, reductionist approaches are required in order to obtain a more complete understanding of the functional capabilities of the gut microbiota. We recently identified microbial bile salt hydrolase (BSH) activity as a gut microbial activity that has the capacity to profoundly alter both local (gastrointestinal) and systemic (hepatic) host functions. Using both germ free and conventionally-raised mouse models we demonstrated that gastrointestinal expression of BSH results in local bile acid deconjugation with concomitant alterations in lipid and cholesterol metabolism, signaling functions and weight gain. Key mediators of cholesterol homeostasis (Abcg5/8), gut homeostasis (RegIIIγ) and circadian rhythm (Dbp) were influenced by elevated BSH in our study. In this addendum we discuss the implications of this work for the rational development of probiotics with the potential to modulate host weight gain.