Torque teno virus (TTV): current status

Hino, Shinjiro; Miyata, Hironori

doi:10.1002/rmv.524

Cited by 168 publications

(145 citation statements)

References 75 publications

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“…In this study, we evaluated the frequency of serum TTV DNA and their genotypes in relation to liver disease in HIV patients as well as in healthy control blood donors .The aim of this study was to investigate the prevalence of SEN-V-D/H and TTV co infection in HIV patients and healthy blood donors in southern Iran. Because of the therapeutic procedures that are frequently associated with bleeding and blood transfusions, HIV patients are at increased risk for infection with blood-borne viruses 7,15 . TTV and SEN-V were detected 34% and 37.33% of healthy blood donors respectively.…”

Section: Discussionmentioning

confidence: 99%

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Molecular characterization of Torque teno virus and SEN virus co-infection with HIV in patients from Southern Iran

Pirouzi

Bahmani

Feizabadi

et al. 2014

Rev. Soc. Bras. Med. Trop.

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Introduction: Torque teno virus (TTV) and SEN virus are circular single-stranded DNA viruses that cause blood-borne infections. The SEN virus (SEN-V) was originally detected in the serum of an injection drug user infected with human immunodefi ciency virus (HIV). Recently TTV was discovered as a potential causative agent of non-A-E hepatitis. The aim of this study was to investigate the prevalence of the SEN-V-D/H and TTV in HIV patients and healthy blood donors in Iran. Methods: One hundred and fi fty HIV patients with a mean age of 50.46 ± 18.46 years and 150 healthy blood donors with a mean age of 48.16 ± 13.73 years were included in this study. TTV and SEN-V were detected by the PCR and were quantitatively assayed by competitive PCR (nested and semi-nested PCR). Restriction fragment length polymorphisms (RFLPs) were used to determine the heterogeneity of TTV. Results: TTV and SEN-V were detected 96 (64%) and 84 (56%) of 150 HIV patients respectively. These rates were 34% (n=51) and 37.33% (n=56) in healthy blood donors (signifi cant, p<0.05). PCR detected SEN-V/TTV DNA from 32 of the healthy blood donors (21.33%), while 65 (43.33%) of HIV patients were positive for SEN-V/TTV DNA. Of 150 HIV patients, 32.66% and 23.33% were positive for SEN-V-H and SEN-V-D, respectively and 18.66% (n=28) were co-infected with SEN-V-D/H. Conclusions: The prevalence of SEN-VD/H and TTV is higher in HIV patients than in healthy blood donors in Southern Iran. Our results suggest that TTV and SEN-V might play a role in the development of liver disease in patients with immunodefi ciency diseases.Keywords: Torque teno virus. SEN virus. HIV. Genotype. Blood donors.Recently, a new virus, designated SEN virus (SEN-V), was isolated from serum of an human immunodefi ciency virus (HIV)-positive patient who was an injection drug user 1 . Nine different SEN-V genotypes have been identifi ed (A to I) which have at least 25% divergence in their nucleotide sequences 2 . The SEN-V-D and SEN-V-H genotypes are most frequently in patients with unknown hepatitis (non-A E hepatitis) but exhibit lower frequencies in the sera of healthy blood donors 3 . In addition Torque teno virus (TTV), also known as transfusiontransmitted virus was fi rst identifi ed in a Japanese patient in 1997 4,5 . Torque teno virus is a circular, single-stranded deoxyribonucleic acid (DNA) virus that chronically infects healthy individuals of all ages worldwide. Substantial data exists describing the prevalence and genetic heterogeneity of TTV in healthy populations and patients infected with HIV. The genome of SEN-V is similar to TTV and both are classifi ed within the circovirus family 5 . Both SEN-V and TTV are single-stranded non-enveloped DNA viruses of 3,800 nucleotides 6,7 . Several studies have shown that in HIV-infected patients the prevalence of TTV is slightly higher compare to healthy blood donors 8 . Puig-Basagoiti et al. described a high TTV prevalence among a large HIV-infected group in Spain 9 . The TTV prevalence of 76% among HIV positive individual ...

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Section: Discussionmentioning

confidence: 99%

“…The genome of SEN-V is similar to TTV and both are classifi ed within the circovirus family 5 . Both SEN-V and TTV are single-stranded non-enveloped DNA viruses of 3,800 nucleotides 6,7 . Several studies have shown that in HIV-infected patients the prevalence of TTV is slightly higher compare to healthy blood donors 8 .…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of Torque teno virus and SEN virus co-infection with HIV in patients from Southern Iran

Pirouzi

Bahmani

Feizabadi

et al. 2014

Rev. Soc. Bras. Med. Trop.

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“…TTV was originally named after the initials of first patient TT, then transfusion-transmitted, and recently renamed "torque teno" virus [73]. Due to the high degree of genomic variability of the putative coding regions [74] and difficulties in expression of full-length TTV protein for antibody testing [75,76], the diagnosis of TTV infection has been dependent on PCR detection of viral DNA using primers specific for the noncoding regions [77].…”

Section: Hres-1/p28 With Viral Peptides and The 70 Kda Protein Of U1 mentioning

confidence: 99%

Molecular mimicry and immunomodulation by the HRES-1 endogenous retrovirus in SLE

et al. 2008

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Genetic and environmental factors are believed to influence development of systemic lupus erythematosus (SLE). Endogenous retroviruses (ERV) correspond to the integrated proviral form of infectious retroviruses, which are trapped within the genome due to mutations. ERV represent a key molecular link between the host genome and infectious viral particles. ERV-encoded proteins are recognized by antiviral immune responses and become targets of autoreactivity. Alternatively, ERV protein may influence cellular processes and the life cycle of infectious viruses. As examples, the HRES-1 human ERV encodes a 28-kDa nuclear autoantigen and a 24-kDa small GTP-ase, termed HRES-1/Rab4. HRES-1/p28 is a nuclear autoantigen recognized by crossreactive antiviral antibodies, while HRES-1/Rab4 regulates surface expression of CD4 and the transferrin receptor (TFR) through endosome recycling. Expression of HRES-1/Rab4 is induced by the tat gene of HIV-1, which in turn down-regulates expression of CD4 and susceptibility to reinfection by HIV-1. CD4 and the TFR play essential roles in formation of the immunological synapse (IS) during normal T-cell activation by a cognate MHC class II peptide complex. The key intracellular transducer of T-cell activation, Lck, is brought to the IS via binding to CD4. T-cell receptorζ (TCRζ) chain binds to the TFR. Abnormal T-cell responses in SLE have been associated with reduced lck and TCRζ chain levels. HRES-1 is centrally located on chromosome 1 at q42 relative to lupus-linked microsatellite markers and polymorphic HRES-1 alleles have been linked to the development of SLE. 1q42 is one of the three most common fragile sites in the human genome, and is inducible by DNA demethylation, a known mechanism of retroviral gene activation. Molecular mimicry and immunomodulation by a ERV, such as HRES-1, may contribute to self-reactivity and abnormal Tand B-cell functions in SLE. (Table I). HERVs are commonly designated as HERV followed by a single letter amino acid code corresponding to a tRNA. The 3′ terminus of tRNA is predicted to initiate reverse transcription by annealing to an 18 nucleotide long primer-binding site (PBS) at the 5′ LTR. While expression of murine ERV can lead to production of infectious virus and cause viremia, no production of infectious virion has been documented by HERV. High copy number of most ERV families makes it difficult to distinguish which members of a group are expressed. Although, no single provirus with intact LTRs and uninterrupted gag, pol, and env ORFs has been identified, the HERV-K ERV, as a family, has been shown to encode gag HHS Public Access Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript the LTR region, is functionally analogous to the HIV-1 rev and HTLV-I/II rex proteins. HERV-K rev binds to both the nuclear export factor Crm1 and to a cis-acting viral RNA to activate nuclear export of unspliced RNAs [39]. Alternatively, the HERV-K LTR is also recognized by HIV-1 rev, suggesting a potential interaction between these exogeneous a...

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“…TTV is a single-stranded DNA virus, of around 3.8 Kb, distantly related to circoviruses and classified in the genus Arnellovirus (Biagini, 2009;Hino & Miyata, 2007). TTV represents in fact a swarm of viruses, which chronically infects human and other animals, and was originally thought to be associated with hepatitis.…”

Section: Other Parenterally-transmitted Viruses Historically Associatmentioning

confidence: 99%

“…One of these genogroups comprises SEN-V, another virus initially associated with hepatitis. Preliminary evidence suggests that some SENwww.intechopen.com V types may be associated to hepatitis, although this association could be a casual event, and then not meaning that SEN-V is actually a true hepatotropic virus (Hino & Miyata, 2007). …”

Section: Other Parenterally-transmitted Viruses Historically Associatmentioning

confidence: 99%

Molecular Evolution of Hepatitis Viruses

Pujol¹,

Jaspe²,

Rangel³

2012

Molecular Virology

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Torque teno virus (TTV): current status

Cited by 168 publications

References 75 publications

Molecular characterization of Torque teno virus and SEN virus co-infection with HIV in patients from Southern Iran

Molecular characterization of Torque teno virus and SEN virus co-infection with HIV in patients from Southern Iran

Molecular mimicry and immunomodulation by the HRES-1 endogenous retrovirus in SLE

Molecular Evolution of Hepatitis Viruses

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