Anti-dengue virus serotype 2 activity of tannins from porcupine dates.

BACKGROUND: Dengue fever is currently endemic in tropical and subtropical countries worldwide and effective drug against DENV infection is still unavailable. Porcupine dates, which are traditionally used to treat dengue fever, might contain potential anti-dengue compounds. Two porcupine dates, black date (BD) and powdery date (PD) from Himalayan porcupine (Hystrix brachyura), were investigated for their antiviral activities against DENV-2 in vitro. METHODS: The methanol crude extracts (MBD and MPD) were prepared from the raw material of porcupine dates. The tannin-rich fractions (BDTF and PDTF) were isolated from their methanol crude extracts using column chromatography. The presence of tannins in BDTF and PDTF extracts was determined by fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) analyses. The cytotoxicity and anti-DENV-2 activities including virus yield inhibition, virucidal, virus attachment and pre-treatment assays of the extracts were examined in Vero cells. RESULTS: Our findings revealed that all the extracts of porcupine dates exhibited antiviral activity against DENV-2 in Vero cells. The IC50 of BDTF and PDTF were 25 µg/mL and 11 µg/mL respectively, while their methanol crude extracts demonstrated lower antiviral efficacy (IC50 ≈ 101-107 µg/mL). BDTF and PDTF also exerted a similar higher virucidal effect (IC50 of 11 µg/mL) than methanol crude extracts (IC50 ≈ 52-66 µg/mL). Furthermore, all the extracts inhibited the attachment of DENV-2 by at least 80%. Pre-treatments of cells with BDTF and PDTF markedly prevented DENV-2 infection when compared to methanol crude extracts. CONCLUSION: This study suggests that porcupine dates possess antiviral properties against DENV-2, which is attributed to its tannin compounds.

Multi-Epitope Peptide-Based and VacciniaBased Universal Influenza Vaccine Candidates Subjected to Clinical Trials

@#In light of the limited protection conferred by current influenza vaccines, immunisation using universal influenza vaccines has been proposed for protection against all or most influenza sub-types. The fundamental principle of universal influenza vaccines is based on conserved antigens found in most influenza strains, such as matrix 2, nucleocapsid, matrix 1 and stem of hemagglutinin proteins. These antigens trigger cross-protective immunity against different influenza strains. Many researchers have attempted to produce the conserved epitopes of these antigens in the form of peptides in the hope of generating universal influenza vaccine candidates that can broadly induce cross-reactive protection against influenza viral infections. However, peptide vaccines are poorly immunogenic when applied individually owing to their small molecular sizes. Hence, strategies, such as combining peptides as multi-epitope vaccines or presenting peptides on vaccinia virus particles, are employed. This review discusses the clinical and laboratory findings of several multi-epitope peptide vaccine candidates and vaccinia-based peptide vaccines. The majority of these vaccine candidates have reached the clinical trial phase. The findings in this study will indeed shed light on the applicability of universal influenza vaccines to prevent seasonal and pandemic influenza outbreaks in the near future.

Universal Oral Vaccine for Influenza Infections / Jurnal Sains Kesihatan Malaysia

Each year, influenza A infections have caused tremendous death rate as high as 300,000-500,000 globally. Althoughthere are effective anti-influenza agents and vaccines, high mutational rate among influenza A viruses renders dramaticdecline in the effectiveness of anti-influenza agents or vaccines in certain individuals. The situation is further complicatedby limitations in influenza vaccine production, for instance, long production period, limited vaccine capacity and lackof cross-protection against various influenza A virus strains. To solve these issues, development of universal influenzavaccine based on conserved antigens such as non-stuctural protein 1 (NS1) has been endeavoured. NS1 protein is highlyconserved in all influenza A virus strains known by far, produced abundantly on infected cell surfaces and responsible formaintaining virulence. Furthermore, cytotoxic T-lymphocytes that are active against NS1 were also reported to be ableto avoid shedding of influenza in hosts. To better inhibit influenza infections, oral immunization has long been proposeddue to feasibility of this method to be implemented and safer for recipients while able to target influenza A viruses fromthe entry point. Lactobacillus has been vastly studied for its roles as bacterial carrier in oral vaccine development dueto its significant probiotic properties. For examples, stimulation of immune responses in oral and airway mucosal layers,high colonization in oral and airway mucosal layers and great natural adjuvant effects. In this light, influenza universaloral vaccine developed using NS1 dan Lactobacillus should be further studied in influenza oral vaccine design.

Synergistic antibacterial effect of co-administering adipose-derived mesenchymal stromal cells and Ophiophagus hannah L-amino acid oxidase in a mouse model of methicillin-resistant Staphylococcus aureus-infected wounds.

BACKGROUND: Mesenchymal stromal cells (MSCs) and Ophiophagus hannah L-amino acid oxidase (Oh-LAAO) have been reported to exhibit antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA). Published data have indicated that synergistic antibacterial effects could be achieved by co-administration of two or more antimicrobial agents. However, this hypothesis has not been proven in a cell- and protein-based combination. In this study, we investigate if co-administration of adipose-derived MSCs and Oh-LAAO into a mouse model of MRSA-infected wounds would be able to result in a synergistic antibacterial effect. METHODS: MSCs and Oh-LAAO were isolated and characterized by standard methodologies. The effects of the experimental therapies were evaluated in C57/BL6 mice. The animal study groups consisted of full-thickness uninfected and MRSA-infected wound models which received Oh-LAAO, MSCs, or both. Oh-LAAO was administered directly on the wound while MSCs were delivered via intradermal injections. The animals were housed individually with wound measurements taken on days 0, 3, and 7. Histological analyses and bacterial enumeration were performed on wound biopsies to determine the efficacy of each treatment. RESULTS: Immunophenotyping and differentiation assays conducted on isolated MSCs indicated expression of standard cell surface markers and plasticity which corresponds to published data. Characterization of Oh-LAAO by proteomics, enzymatic, and antibacterial assays confirmed the identity, purity, and functionality of the enzyme prior to use in our subsequent studies. Individual treatments with MSCs and Oh-LAAO in the infected model resulted in reduction of MRSA load by one order of magnitude to the approximate range of 6 log10 colony-forming units (CFU) compared to untreated controls (7.3 log10 CFU). Similar wound healing and improvements in histological parameters were observed between the two groups. Co-administration of MSCs and Oh-LAAO reduced bacterial burden by approximately two orders of magnitude to 5.1 log10 CFU. Wound closure measurements and histology analysis of biopsies obtained from the combinational therapy group indicated significant enhancement in the wound healing process compared to all other groups. CONCLUSIONS: We demonstrated that co-administration of MSCs and Oh-LAAO into a mouse model of MRSA-infected wounds exhibited a synergistic antibacterial effect which significantly reduced the bacterial count and accelerated the wound healing process.

Significant Replication Time-points of Avian Influenza A Virus Strain H5N1 in Madin-Darby Canine Kidney Cells / Jurnal Sains Kesihatan Malaysia

The occasional influenza pandemics and the seasonal influenza epidemics have destroyed millions of lives since the last century. It is therefore necessary to understand the virus replication patterns as this provides essential information on the virus infectivity, pathogenicity and spread patterns. This study aimed to investigate the replication of avian influenza A virus H5N1 (A/Chicken/Malaysia/5858/2004) in MDCK cells. In this study, the TCID50 (50% tissue culture infectious dose) of AIV H5N1 was first determined. The MDCK cells were then infected with AIV H5N1 at TCID50 for 0-48 h. The CPE (cytopathic effect) was observed and cell death was determined hourly. The virus-infected cells and media were subsequently collected for gene analysis. The results showed that the TCID50 of AIV H5N1 was 10-9 dilution. The CPE percentage showed a strong and positive correlation with the infection period (r = 1.0, n = 9, p 0.05) and infected cell (r = 0.73, n = 9, p < 0.05) were also positively correlated with the infection period. In conclusion, although CPE started to be observed in the early time points of infection, however, the M2 gene was only amplified from the infected media and cells after 48 h and 24 h, respectively. This signifies that AIV H5N1 used in this study is pathogenic and it is able to cause severe cytopathology to host cells even at low virus load.