HPgV-2 (also known as human pegivirus type 2) is the second human
pegivirus discovered.
[ It was first identified in 2005 in blood of transfusion recipients and initially named ''hepegivirus 1'' because it shared some genetic features with both pegiviruses and hepaciviruses.] HPgV-2 was later independently discovered by another group in the blood of a HCV-infected patient who had undergone multiple blood transfusions and died from sepsis
Sepsis is a potentially life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs.
This initial stage of sepsis is followed by suppression of the immune system. Common signs and s ...
of unclear etiology. It was then named ''human pegivirus 2''. HPgV-2 is now classified in the ''Pegivirus'' genus as part of ''Pegivirus columbiaense'' species.
HPgV-2 is a blood-borne virus that causes chronic long-term infections much like hepatitis C virus
The hepatitis C virus (HCV) is a small (55–65 nm in size), enveloped, positive-sense single-stranded RNA virus of the family ''Flaviviridae''. The hepatitis C virus is the cause of hepatitis C and some cancers such as liver cancer ( hepatoc ...
(HCV) and GB virus C (HPgV) – the first human pegivirus to have been discovered – but is not known to be associated with any disease. It usually infects people who are already infected by HCV and has the prevalence around 1–2% in such persons. Its prevalence in HCV/HIV
The human immunodeficiency viruses (HIV) are two species of '' Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the im ...
coinfected subjects is still higher – up to 10%. However, its prevalence in the general population in China and USA is very low at 0.1–0.2%.[ The chronic infection by HPgV-2 is maintained in presence of antienvelop antibodies as is the case for HCV chronic infections, whereas in case of GB virus C, appearance of antibodies usually leads to resolution of the infection.]
HPgV-2 is a positive-sense single-stranded RNA virus
Positive-strand RNA viruses (+ssRNA viruses) are a group of related viruses that have positive-sense, single-stranded genomes made of ribonucleic acid. The positive-sense genome can act as messenger RNA (mRNA) and can be directly translated i ...
with the genome length around 9,800 nucleotides. Its genomic organization is similar to that of other flaviviruses
''Flavivirus'', renamed ''Orthoflavivirus'' in 2023, is a genus of positive-strand RNA viruses in the family ''Flaviviridae''. The genus includes the West Nile virus, dengue virus, tick-borne encephalitis virus, yellow fever virus, Zika viru ...
. It produces a single polyprotein translated from a single open reading frame
In molecular biology, reading frames are defined as spans of DNA sequence between the start and stop codons. Usually, this is considered within a studied region of a prokaryotic DNA sequence, where only one of the six possible reading frames ...
, which is then cleaved by the viral protease
A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalysis, catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products ...
into multiple viral proteins: two structural envelope glycoprotein
Glycoproteins are proteins which contain oligosaccharide (sugar) chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known a ...
s (E1 and E2), six nonstructural proteins (NS2, NS3, NS4A, NS4B, NS5A, and NS5B), a truncated core protein (S, nucleocapsid
A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or ma ...
), and an X protein of unknown function. Different strains of HPgV-2 have sequence homology of 90% or more.[
]
References
{{Taxonbar, from=Q49000682
Pegiviruses