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Endogenous Vaults: Roles and functions in health and diseases

Dionysia Marinou, Vasiliki Pitiriga, Maria Mavrouli, Athanassios Tsakris, John Routsias
Department of Microbiology, Medical School, National & Kapodistrian University of Athens, Athens, Greece

Vaults are large ribonucleoprotein particles, with a molecular weight of 13 MDa, in the cytoplasm
of many eukaryotic cells. They first reported in the mid-1980s. These particles consist of the Μajor
Vault Protein (MVP), the Vault Poly- (ADP-Ribose) -Polymerase (VPARP), the Telomerase-associated
Protein (TEP1) and small RNAs (vRNA). There are approximately 10.000 vault particle per cell.
Their majority is detected in cytoplasm, where they can interact with cytoskeletal elements. A
small amount of vaults is also found to be associated with the nucleus. Little are known about
the biological role of vault particles. However, their structure and their cellular detection show
that these complexes have a role in intracellular transport. Recent studies support that vaults
have, also a role in multidrug resistance (MDR) in cancer. Some other functions have also attributed
to these particles, such as participation in infection process, signal pathways, cell survival
and DNA repairing. Recent studies have also demonstrated that vaults have the potential to serve
as transporters. Vaults could be engineered and used as nanocapsules in order to carry vaccines,
drugs or other molecules in target locations and activate immune responses. Finally, preliminary
findings in our laboratory, show that MVP is increased in patients with an inflammation of infectious etiology,
indicating a role of vaults in infection process as it has already been supported in recent studies.

Key words
Vaults, MVP, infection, vaccine

HLA-Human Leukocyte Antigens and their genetic polymorphisms in Hepatitis B virus infection (HBV-infection)

Evangelia Myserli1, Asimina Fylaktou2, Georgia Gioula1
1Laboratory of Hepatology, B Clinic of Internal Medicine, School of Medicine, Faculty of Health Sciences, Aristotle
University of Thessaloniki, Greece;
2National Regional Histocompatibility Center, Department of Immunology, Hippokration General Hospital,
Thessaloniki, Greece.

The variety of HBV infection clinical phenotypes depends either on environment or on both host’s
and viral genetics. The Major Histocompatibility Complex – MHC encodes the expression of
Human Leucocyte Antigens – HLA, the main molecules of host’s immune response. As a result,
the polymorphism of these genes affects the clinical outcome of every infection. This assumption
was also documented for Hepatitis B virus (HBV) infection by Genome Wide Association Studies
– GWAS held in different ethnic groups. Certain polymorphisms in both HLA Class I and the Class
II genes have been associated with susceptibility to chronic HBV infection or protection against
the later. In a series of studies, spontaneous clearance of HBsAg or HBV eradication in chronic
carriers are associated with gene polymorphisms in HLA-DR locus and especially HLA-DP one.
Vertical transmission of the virus has also been associated with specific HLA alleles. Furthermore,
Single Nucleotide Polymorphisms (SNPs) of HLA genes, especially in the HLA Class II region seem
to affect the responsiveness to HBV vaccination. However, the observations about the correlation
of the HLA genes polymorphism with the HBV infection phenotype vary greatly among people
of different nationalities and may often are conflicting. It is therefore necessary to conduct further
studies in a global scale in order to clarify the role of HLA polymorphism in the pathogenesis of
HBV infection and to enable personalized monitoring of these patients by means of suitable genetic
markers in the future.

Key words
HLA polymorphisms, HBV infection, hepatitis Β, Major Histocompatibility complex

Comparative evaluation of selective culture and PCR for detection of Fusobacterium necrophorum  and Fusobacterium nucleatum in throat specimens

Victoria Mela1,2, Angeliki Pantazatou2, Athanassios Tsakris1, Georgios L. Petrikkos3, Sotirios Tsiodras3,
Anna Psarrou4, and Joseph Papaparaskevas1
1Department of Microbiology, Medical School, National and Kapodistrian University of Athens, Greece
2Department of Microbiology, “Laikon” General Hospital,Athens, Greece
3Fourth Department of Internal Medicine, Medical School, National and Kapodistrian University of Athens,
“Attikon” University Hospital,Athens,Greece
4First Department of Internal Medicine, 401 General Military Hospital, Athens, Greece

Culture on selective media (Fusobacteriumselective agar supplemented with 4 mg/L vancomycin
and 8 mg/L neomycin) was compared to PCR (rpoB and haem genes for Fusobacterium necrophorum,
16S rDNA fragment specific for Fusobacterium nucleatum) for direct detection of the species
in throat specimens of 88 patients with sore throat and pharyngotonsilits.
Among the 49 culture-positive specimens, culture and PCR revealed identical positive results in
38 (43.1%) and eight (9.1%) patients for F. nucleatum and F. necrophorum, respectively, whilst in
two more patients (2.3%), both pathogens were detected by both methods. Only a single
F. nucleatum culture-positive specimen was PCR-negative. In contrast, among the remaining 39
culture-negative specimens, five (5.7%) and two (2.3%) were positive by PCR for F. nucleatum and F.
necrophorum, respectively. Sub-species identification revealed that all F. necrophorum isolates
were identified as F. necrophorumssp. funduliforme. Sensitivity, specificity, PPV and NPV of the 16S
rDNA PCR (F. nucleatum detection) were 97.6, 89.4, 88.9 and 97.7%, respectively, whilst the respective
values for the rpoB PCR (F. necrophorumdetection) were 100.0, 97.4, 83.3 and 100.0%, as
compared to culture.
In conclusion, PCR proved of higher diagnostic yield than culture and detected both species in
culture-negative specimens. As similar results have been obtained for other anaerobic species,
the golden standard anaerobic culture seems to be insufficient for detecting Fusobacterium spp.
in the area of molecular microbiology and needs further re-evaluation.

Key words
PCR; culture; Fusobacterium nucleatum; Fusobacterium necrophorum; pharyngotonsilitis

Epstein-Barr Virus (EBV) Infection and HIV Antibody Reactivity in a First Time Donor

Fratzeska Bazigou1, Aliki Velissari1, Afroditi Cheropoulou2, Sofia Baliaga2, Lilian Kavallierrou1
1Blood Transfusion Service Amalia Fleming Hospital, 2Blood Transfusion Service Sismanoglio Hospital
General Hospital of Attiki Sismanoglio – Amalia Fleming

An 18-years-old female student was screened as a first-time blood (plateletpheresis) donor and
was found to have a highly positive HIV Ab serological test. Negative Western Blot (WB), HIV p24
antigen and NAT HCV RNA/HIV-1 RNA/HBV DNA assays confirmed that the donor was not infected
with HIV. The use of other laboratory tests revealed an Epstein Barr Virus infection with
positive EBV Viral Capsid Antigen (VCA IgM and VCA IgG) antibodies and also positive heterophile
antibodies. False-positive results of HIV infection by serological tests, relate to multiple factors
and underlying disease states. Crossreactivity can be rarely seen in patients with other viral diseases,
whereas heterophile antibodies can cause false positive results when binding to nonhuman
antibodies used in commercially available immunoassays.

Key words
Nonspecific reactivity of HIV; EBV infection;Blood donor

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