Comparative Evaluation of Recombinant and Acellular Pertussis Vaccines in a Murine Model

Since the 2000s, sporadic outbreaks of whooping cough have been reported in advanced countries, where the acellular pertussis vaccination rate is relatively high, and in developing countries. Small-scale whooping cough has also continued in many countries, due in part to the waning of immune protection after childhood vaccination, necessitating the development of an improved pertussis vaccine and vaccination program. Currently, two different production platforms are being actively pursued in Korea; one is based on the aP (acellular pertussis) vaccine purified from B. pertussis containing pertussis toxoid (PT), filamentous hemagglutin (FHA) and pertactin (PRN), and the other is based on the recombinant aP (raP), containing genetically detoxified pertussis toxin ADP-ribosyltransferase subunit 1 (PtxS1), FHA, and PRN domain, expressed and purified from recombinant E. coli. aP components were further combined with diphtheria and tetanus vaccine components as a prototype DTaP vaccine by GC Pharma (GC DTaP vaccine). We evaluated and compared the immunogenicity and the protective efficacy of aP and raP vaccines in an experimental murine challenge model: humoral immunity in serum, IgA secretion in nasal lavage, bacterial clearance after challenge, PTx (pertussis toxin) CHO cell neutralization titer, cytokine secretion in spleen single cell, and tissue resident memory CD4+ T cell (CD4+ TRM cell) in lung tissues. In humoral immunogenicity, GC DTaP vaccines showed high titers for PT and PRN and showed similar patterns in nasal lavage and IL-5 cytokine secretions. The GC DTaP vaccine and the control vaccine showed equivalent results in bacterial clearance after challenge, PTx CHO cell neutralization assay, and CD4+ TRM cell. In contrast, the recombinant raP vaccine exhibited strong antibody responses for FHA and PRN, albeit with low antibody level of PT and low titer in PTx CHO neutralization assay, as compared to control and GC DTaP vaccines. The raP vaccine provided a sterile lung bacterial clearance comparable to a commercial control vaccine after the experimental challenge in murine model. Moreover, raP exhibited a strong cytokine response and CD4+ TRM cell in lung tissue, comparable or superior to the experimental and commercial DTaP vaccinated groups. Contingent on improving the biophysical stability and humoral response to PT, the raP vaccine warrants further development as an effective alternative to aP vaccines for the control of a pertussis outbreak.

Detoxification of the Lipid Peroxidation Aldehyde, 4-Hydroxynonenal, by Apple Phloretin In Vitro and in Mice

4-Hydroxy-2-nonenal (4-HNE) is a secondary cytotoxic product generated from lipid peroxidation of polyunsaturated fatty acids (PUFAs). The accumulation of 4-HNE can covalently modify biomolecules, such as DNA and proteins, leading to various pathological conditions. Apple phloretin has been shown to be able to trap 4-HNE in vitro, but the trapping mechanisms of 4-HNE by phloretin are not fully understood. Moreover, whether the in vitro trapping efficacy of phloretin toward 4-HNE could be transferred into in vivo environments has never been investigated. In the present study, we observed the formation of 4-HNE conjugates of phloretin increased as phloretin decreased during the in vitro incubation. We then purified and characterized three mono-4-HNE-conjugates of phloretin using NMR and LC-MS/MS techniques. We thereafter demonstrated that apple phloretin could scavenge in vivo 4-HNE via the formation of at least three mono-4-HNE-conjugates of phloretin in a dose-dependent manner in mice after oral administration of three doses of phloretin (25, 100, and 400 mg/kg). The findings from this study pave the way to understanding how dihydrochalcones could act as effective scavengers of 4-HNE by working as sacrificial nucleophiles in vivo, thereby preventing or reducing the risk of 4-HNE-associated chronic diseases.

Metabolic Investigation on the Interaction Mechanism between Dietary Dihydrochalcone Intake and Lipid Peroxidation Product Acrolein Reduction

SCOPE

Acrolein (ACR), a lipid peroxidation product, pathologically participates in various chronic diseases. In vitro evidence suggestes that dietary dihydrochalcones (DHCs) potentiate safe and alternative therapeutics to synthetic pharmaceuticals for ACR scavenging. Here, to investigate whether ingested DHCs could trap ACR and thereof result in reductions in endogenous ACR in mice is aimed.

METHODS AND RESULTS

Three doses of phloretin (25, 100, and 400 mg kg-1 ), a major dietary DHC, are orally administrated to mice and 24 h urine and fecal samples are collected, respectively. High-resolution MS-based targeted metabolomics reveal for the first time that phloretin and its oxidized metabolite are able to trap endogenous ACR via formation of ACR conjugates. Quantification further demonstrate that a) more than 13% of ingested phloretin can dose-dependently trap 0.77-9.92 nmol of ACR within 24 h; b) phloretin ingestion leads to marked reductions in both free ACR and ACR metabolites in mouse urine compared to control; and c) trapping reactions by phloretin can account for up to 20.1% of the total decreases in endogenous ACR, depending on the administration doses.

CONCLUSION

Findings from this study indicate that regular consumption of DHCs-rich diets holds great promise to alleviate the development of ACR-associated chronic diseases.

A pathogenic DMC1 frameshift mutation causes nonobstructive azoospermia but not primary ovarian insufficiency in humans

Nonobstructive azoospermia (NOA) and diminished ovarian reserve (DOR) are two disorders that can lead to infertility in males and females. Genetic factors have been identified to contribute to NOA and DOR. However, the same genetic factor that can cause both NOA and DOR remains largely unknown. To explore the candidate pathogenic gene that causes both NOA and DOR, we conducted whole-exome sequencing (WES) in a non-consanguineous family with two daughters with DOR and a son with NOA. We detected one pathogenic frameshift variant (NM_007068:c.28delG, p. Glu10Asnfs*31) following a recessive inheritance mode in a meiosis gene DMC1 (DNA meiotic recombinase 1). Clinical analysis showed reduced antral follicle number in both daughters with DOR, but metaphase II oocytes could be retrieved from one of them. For the son with NOA, no spermatozoa were found after microsurgical testicular sperm extraction. A further homozygous Dmc1 knockout mice study demonstrated total failure of follicle development and spermatogenesis. These results revealed a discrepancy of DMC1 action between mice and humans. In humans, DMC1 is required for spermatogenesis but is dispensable for oogenesis, although the loss of function of this gene may lead to DOR. To our knowledge, this is the first report on the homozygous frameshift mutation as causative for both NOA and DOR and demonstrating that DMC1 is dispensable in human oogenesis.

Similarities of Variant Creutzfeldt-Jakob Disease Strain in Mother and Son in Spain to UK Reference Case

We investigated transmission characteristics of variant Creutzfeldt-Jakob disease in a mother and son from Spain. Despite differences in patient age and disease manifestations, we found the same strain properties in these patients as in UK vCJD cases. A single strain of agent appears to be responsible for all vCJD cases to date.

Vitamin D3 supplementation of a high fat high sugar diet ameliorates prediabetic phenotype in female LDLR-/- and LDLR+/+ mice

INTRODUCTION

Fatty liver disease is prevalent in populations with high caloric intake. Nutritherapeutic approaches are being considered, such as supplementary Vitamin D3 , to improve aspects of metabolic syndrome, namely fatty liver disease, hyperlipidemia, and insulin resistance associated with obesity.

METHODS

We analyzed female LDLR-/- and LDLR+/+ mice on a 10-week diabetogenic diet for markers of fatty liver disease, metabolic strain, and inflammation.

RESULTS

The groups on a high fat high sugar diet with supplementary Vitamin D3 , in comparison with the groups on a high fat high sugar diet alone, showed improved transaminase levels, significantly less hypertriglyceridemia and hyperinsulinemia, and histologically, there was less pericentral hepatic steatosis. Levels of non-esterified fatty acids and lipid peroxidation products were significantly lower in the group supplemented with additional Vitamin D3 , as were systemic markers of inflammation (serum endotoxin and IL-6). M2 macrophage phenotype predominated in the group supplemented with additional Vitamin D3 . Beneficial changes were observed as early as five weeks' supplementation with Vitamin D3 and extended to restoration of high fat high sugar diet induced decrease of bone mineral density.

CONCLUSION

In summary, Vitamin D3 was a significantly beneficial dietary additive to blunt a prediabetic phenotype in diet-induced obesity of female LDLR-/- and LDLR+/+ mice.

Swertisin ameliorates pre-pulse inhibition deficits and cognitive impairment induced by MK-801 in mice

Swertisin, a plant-derived C-glucosylflavone, is known to have antidiabetic, anti-inflammatory and antioxidant effects. In the present study, we investigated in mice the effects of swertisin on glutamatergic dysfunction induced by dizocilpine (MK-801), a non-competitive N-methyl-D-aspartate receptor antagonist. In the Acoustic Startle Response test, their MK-801-induced (given 0.2 mg/kg i.p.) pre-pulse inhibition deficit was significantly attenuated by the administration of swertisin (30 mg/kg p.o.). In the Novel Object Recognition Test, the recognition memory impairments that were induced by MK-801 (0.2 mg/kg, given i.p.) were also reversed by administration of swertisin (30 mg/kg p.o.). In addition, swertisin normalized the MK-801-induced elevation of phosphorylation levels of Akt and GSK-3β signaling molecules in the prefrontal cortex. These results indicated that swertisin may be useful in managing the symptoms of schizophrenia, including sensorimotor gating disruption and cognitive impairment, and that these behavioral outcomes may be related to Akt-GSK-3β signaling in the prefrontal cortex.

Computer-aided analyses of mouse retinal OCT images - an actual application report

PURPOSE

There is a need for automated retinal optical coherence tomography (OCT) image analysis tools for quantitative measurements in small animals. Some image processing techniques for retinal layer analysis have been developed, but reports about how useful those techniques are in actual animal studies are rare. This paper presents the use of a retinal layer detection method we developed in an actual mouse study that involves wild type and mutated mice carrying photoreceptor degeneration.

METHODS

Spectral domain OCT scanning was performed by four experimenters over 12 months on 45 mouse eyes that were wild-type, deficient for ephrin-A2 and ephrin-A3, deficient for rhodopsin, or deficient for rhodopsin, ephrin-A2 and ephrin-A3. The thickness of photoreceptor complex between the outer plexiform layer and retinal pigment epithelium was measured on two sides of the optic disc as the biomarker of retinal degeneration. All the layer detection results were visually confirmed.

RESULTS

Overall, 96% (8519 out of 9000) of the half-side images were successfully processed using our technique in a semi-automatic manner. There was no significant difference in success rate between mouse lines (p = 0.91). Based on a human observer's rating of image quality for images successfully and unsuccessfully processed, the odds ratios for 'easily visible' images and 'not clear' images to be successfully processed is 62 and 4, respectively, against 'indistinguishable' images. Thickness of photoreceptor complex was significantly different across the quadrants compared (p < 0.001). It was also found that the average thickness based on 4-point sparse sampling was not significantly different from the full analysis, while the range of differences between the two methods could be up to about 6 μm or 16% for individual eyes. Differences between mouse lines and progressive thickness reduction were revealed by both sampling measures.

CONCLUSIONS

Although the thickness of the photoreceptor complex layer is not even, manual sparse sampling may be as sufficiently accurate as full analysis in some studies such as ours, where the error of sparse sampling was much smaller than the effect size of rhodopsin deficiency. It is also suggested that the image processing method can be useful in actual animal studies. Even for images poorly visible to human eyes the image processing method still has a good chance to extract the complex layer.

Puberty in females enhances the risk of an outcome of multiple sclerosis in children and the development of central nervous system autoimmunity in mice

BACKGROUND

For reasons that remain unclear, three times more women develop multiple sclerosis (MS) than men. This preponderance among women is evident only after 12 years of age, implicating pubertal factors in the risk of MS.

OBJECTIVE

To investigate the influence of female puberty on central nervous system (CNS) autoimmunity.

METHODS

We examined the relationship between age of menarche on MS outcomes in 116 female children (< 16 years old) whom presented with incident 'acquired demyelinating syndromes' (ADS) and were followed prospectively in the national Canadian Pediatric Demyelinating Disease Study, from 2004-2013. Furthermore, we directly investigated the effects of puberty on susceptibility to experimental autoimmune encephalomyelitis (EAE) in two groups of female mice that differed only in their pubertal status.

RESULTS

In the ADS children, a later age of menarche was associated with a decreased risk of subsequent MS diagnosis. This relationship persisted, after accounting for patient age at ADS presentation and the presence of ≥1 T2 lesions on brain magnetic resonance imaging (MRI), with a hazard ratio (HR) of 0.64; and additional factors that associate with MS outcomes in ADS children, including low vitamin D levels. Furthermore, we found female mice that had transitioned through puberty were more susceptible to EAE than age-matched, pre-pubertal mice.

CONCLUSION

Puberty in females enhances CNS autoimmune mechanisms that lead to MS in humans and EAE in mice.

The effects of acute nicotine on contextual safety discrimination

Anxiety disorders, such as post-traumatic stress disorder (PTSD), may be related to an inability to distinguish safe versus threatening environments and to extinguish fear memories. Given the high rate of cigarette smoking in patients with PTSD, as well as the recent finding that an acute dose of nicotine impairs extinction of contextual fear memory, we conducted a series of experiments to investigate the effect of acute nicotine in an animal model of contextual safety discrimination. Following saline or nicotine (at 0.0275, 0.045, 0.09 and 0.18 mg/kg) administration, C57BL/6J mice were trained in a contextual discrimination paradigm, in which the subjects received presentations of conditioned stimuli (CS) that co-terminated with a foot-shock in one context (context A (CXA)) and only CS presentations without foot-shock in a different context (context B (CXB)). Therefore, CXA was designated as the 'dangerous context', whereas CXB was designated as the 'safe context'. Our results suggested that saline-treated animals showed a strong discrimination between dangerous and safe contexts, while acute nicotine dose-dependently impaired contextual safety discrimination (Experiment 1). Furthermore, our results demonstrate that nicotine-induced impairment of contextual safety discrimination learning was not a result of increased generalized freezing (Experiment 2) or contingent on the common CS presentations in both contexts (Experiment 3). Finally, our results show that increasing the temporal gap between CXA and CXB during training abolished the impairing effects of nicotine (Experiment 4). The findings of this study may help link nicotine exposure to the safety learning deficits seen in anxiety disorder and PTSD patients.

The influence of test experience and NK1 receptor antagonists on the performance of NK1R-/- and wild type mice in the 5-Choice Serial Reaction-Time Task

Genetically-altered mice, lacking functional NK1 receptors (NK1R-/-), express abnormal behaviours that are prominent in Attention Deficit Hyperactivity Disorder: namely, inattentiveness and impulsivity (indicated by their greater % omissions and premature responses in the 5-Choice Serial Reaction-Time Task (5-CSRTT) and locomotor hyperactivity. We investigated how behaviour in the 5-CSRTT is affected by repeated testing and whether the abnormalities expressed by NK1R-/- mice are mimicked by treating wild type mice with a NK1R antagonist (L 733060 or RP 67580; 5 or 10 mg/kg). Repeated testing with a variable (VITI) or fixed, prolonged (LITI) intertrial interval reduced % omissions. Premature responses also declined, but only in NK1R-/- mice, in the VITI test. By contrast, perseveration increased in both genotypes. RP 67580 (10 mg/kg) increased the % omissions in both genotypes in the VITI, an action which cannot be attributed to NK1R antagonism. Neither drug affected perseveration. However, for premature responses, the response profile suggested that the low and high doses of RP 67580 (VITI) and L 733060 (LITI) had opposing effects on this behaviour. We infer that the effect of NK1R antagonists in the 5-CSRTT is confounded by animals' test experience and non-specific drug effects at sites other than NK1R, possibly L-type Ca²⁺(v) channels.

MOG extracellular domain (p1-125) triggers elevated frequency of CXCR3+ CD4+ Th1 cells in the CNS of mice and induces greater incidence of severe EAE

BACKGROUND

Myelin-specific T cells are implicated in multiple sclerosis (MS) and drive experimental autoimmune encephalomyelitis (EAE). EAE is commonly induced with short peptides, whereas in MS, whole myelin proteins are available for immune response. We asked whether immunization with the immunoglobulin-like domain of myelin oligodendrocyte glycoprotein (MOG(Igd), residues 1-125) might induce distinct CD4+ T-cell response and/or a stronger CD8+ T-cell response, compared to the 21 amino acid immunodominant MHC II-associating peptide (p35-55).

OBJECTIVES

Compare both EAE and T-cell responses in C57BL/6 mice immunized with MOG(Igd) and MOG p35-55.

METHODS

Cytokine production, and chemokine receptor expression by CD4+ and CD8+ T cells in the mouse central nervous system (CNS), were analyzed by flow cytometry.

RESULTS

MOG(Igd) triggered progression to more severe EAE than MOG p35-55, despite similar time of onset and overall incidence. EAE in MOG(Igd)-immunized mice was characterized by an increased percentage of CXCR3+ interferon-γ-producing CD4+ T cells in CNS. The CD8+ T-cell response to both immunogens was similar.

CONCLUSIONS

Increased incidence of severe disease following MOG(Igd) immunization, accompanied by an increased percentage of CD4+ T cells in the CNS expressing CXCR3 and producing interferon-γ, identifies a pathogenic role for interferon-γ that is not seen when disease is induced with a single Major Histocompatibility Complex (MHC) II-associating epitope.

Immune ambivalence: The schizophrenic bleomycin

In addition to cytotoxic effects, anticancer agents can exert multiple immunomodulatory functions. We have recently described the molecular mechanisms whereby bleomycin can 1) promote endoplasmic reticulum stress, causing the immunogenic death of cancer cells and hence strengthening antitumor CD8⁺ T cell responses; and 2) induce the secretion of transforming growth factor β (TGFβ), which stimulates regulatory T cells. This suggests that bleomycin may be favorably combined with TGFβ-targeting strategies.