Resveratrol-Mediated Attenuation of Staphylococcus aureus Enterotoxin B-Induced Acute Liver Injury Is Associated With Regulation of microRNA and Induction of Myeloid-Derived Suppressor Cells

Resveratrol (RES) is a polyphenolic compound found abundantly in plant products including red grapes, peanuts, and mulberries. Because of potent anti-inflammatory properties of RES, we investigated whether RES can protect from Staphylococcal enterotoxin B (SEB)-induced acute liver injury in mice. SEB is a potent super antigen that induces robust inflammation and releases inflammatory cytokines that can be fatal. We observed that SEB caused acute liver injury in mice with increases in enzyme aspartate transaminase (AST) levels, and massive infiltration of immune cells into the liver. Treatment with RES (100 mg/kg body weight) attenuated SEB-induced acute liver injury, as indicated by decreased AST levels and cellular infiltration in the liver. Interestingly, RES treatment increased the number of myeloid derived suppressor cells (MDSCs) in the liver. RES treatment led to alterations in the microRNA (miR) profile in liver mononuclear cells (MNCs) of mice exposed to SEB, and pathway analysis indicated these miRs targeted many inflammatory pathways. Of these, we identified miR-185, which was down-regulated by RES, to specifically target Colony Stimulating Factor (CSF1) using transfection studies. Moreover, the levels of CSF1 were significantly increased in RES-treated SEB mice. Because CSF1 is critical in MDSC induction, our studies suggest that RES may induce MDSCs by down-regulating miR-185 leading to increase the expression of CSF1. The data presented demonstrate for the first time that RES can effectively attenuates SEB-induced acute liver injury and that this may result from its action on miRs and induction of MDSCs

Experimental Infection of Cynomolgus Macaques (Macaca fascicularis) with Aerosolized Monkeypox Virus

Monkeypox virus (MPXV) infection in humans results in clinical symptoms very similar to ordinary smallpox. Aerosol is a route of secondary transmission for monkeypox, and a primary route of smallpox transmission in humans. Therefore, an animal model for aerosol exposure to MPXV is needed to test medical countermeasures. To characterize the pathogenesis in cynomolgus macaques (Macaca fascicularis), groups of macaques were exposed to four different doses of aerosolized MPXV. Blood was collected the day before, and every other day after exposure and assessed for complete blood count (CBC), clinical chemistry analysis, and quantitative PCR. Macaques showed mild anorexia, depression, and fever on day 6 post-exposure. Lymphadenopathy, which differentiates monkeypox from smallpox, was observed in exposed macaques around day 6 post-exposure. CBC and clinical chemistries showed abnormalities similar to human monkeypox cases. Whole blood and throat swab viral loads peaked around day 10, and in survivors, gradually decreased until day 28 post-exposure. Survival was not dose dependent. As such, doses of 4×104 PFU, 1×105 PFU, or 1×106 PFU resulted in lethality for 70% of the animals, whereas a dose of 4×105 PFU resulted in 85% lethality. Overall, cynomolgus macaques exposed to aerosolized MPXV develop a clinical disease that resembles that of human monkeypox. These findings provide a strong foundation for the use of aerosolized MPXV exposure of cynomolgus macaques as an animal model to test medical countermeasures against orthopoxviruses

ACAM2000™: The new smallpox vaccine for United States Strategic National Stockpile

Aysegul Nalca, Elizabeth E ZumbrunCenter for Aerobiological Sciences, US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, MD, USAAbstract: Smallpox was eradicated more than 30 years ago, but heightened concerns over bioterrorism have brought smallpox and smallpox vaccination back to the forefront. The previously licensed smallpox vaccine in the United States, Dryvax® (Wyeth Laboratories, Inc.), was highly effective, but the supply was insufficient to vaccinate the entire current US population. Additionally, Dryvax® had a questionable safety profile since it consisted of a pool of vaccinia virus strains with varying degrees of virulence, and was grown on the skin of calves, an outdated technique that poses an unnecessary risk of contamination. The US government has therefore recently supported development of an improved live vaccinia virus smallpox vaccine. This initiative has resulted in the development of ACAM2000™ (Acambis, Inc.™), a single plaque-purified vaccinia virus derivative of Dryvax®, aseptically propagated in cell culture. Preclinical and clinical trials reported in 2008 demonstrated that ACAM2000™ has comparable immunogenicity to that of Dryvax®, and causes a similar frequency of adverse events. Furthermore, like Dryvax®, ACAM2000™ vaccination has been shown by careful cardiac screening to result in an unexpectedly high rate of myocarditis and pericarditis. ACAM2000™ received US Food and Drug Administration (FDA) approval in August 2007, and replaced Dryvax® for all smallpox vaccinations in February 2008. Currently, over 200 million doses of ACAM2000™ have been produced for the US Strategic National Stockpile. This review of ACAM2000™ addresses the production, characterization, clinical trials, and adverse events associated with this new smallpox vaccine.Keywords: smallpox, vaccinia, variola, vaccine, efficacy, safet

Standardization of the Filovirus Plaque Assay for Use in Preclinical Studies

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Serum chemistries in macaques exposed to aerosolized MPXV.

<p>The dotted lines indicate the normal reference range; n: number of animals. Graphs show average <b>A</b>) total protein, <b>B</b>) albumin, <b>C</b>) lactate dehydrogenase (LDH), <b>D</b>) C-reactive protein, <b>E</b>) aspartate transaminase (AST), <b>F</b>) and alanine transaminase (ALT), <b>G</b>) urea nitrogen.</p

Average number of leukocytes and platelets in macaques after exposed to aerosolized MPXV.

<p>The dotted lines indicate the normal reference range; n: number of animals. Graphs are shown for <b>A</b>) total white blood cells (WBC), <b>B</b>) percentage of granulocytes (GR), <b>C</b>) percentage of lymphocytes (LY), <b>D</b>) platelets (PLT) for all MPXV dosage groups, and survivors versus non-survivors (right).</p

Pathology and presence of MPXV antigen in lung tissue.

<p>Figures <b>A–D</b> are histological sections of lung tissues from cynomolgus macaques infected via aerosolized MPXV. Positive immunoreactivity for orthopoxvirus antigen, shown as brown staining, is associated with necrotizing lesions primarily concentrated around bronchi and bronchioles. [Immunoperoxidase method using rabbit polyclonal antibody to vaccinia virus; original magnification ×40 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0012880#pone-0012880-g006" target="_blank">Figure 6A</a>) or ×20 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0012880#pone-0012880-g006" target="_blank">Figure 6</a> B, C, D)]. <b>A</b>) 4×10⁴ PFU (day 10 post-exposure). <b>B</b>) 1×10⁵ PFU (day 8 post-exposure). <b>C</b>) 4×10⁵ PFU (day 11 post-exposure). <b>D</b>) 1×10⁶ PFU (day 9 post-exposure). <b>E</b>) Percent immunoreactivity in the lungs of non-survivors by dosage group, measured by digital microscopy image analysis.</p