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Other Single-Stranded DNA Viruses
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
Concerning Torque teno virus (TTV) proteins, Mueller et al. (2008) expressed the ORF1, the ORF1 splace variants ORF1/1 and ORF1/2, ORF2, ORF2/2, ORF3, and ORF4 of human TTV, where ORF1 was known to encode capsid protein, in human hepatocellular carcinoma Huh7 cells. The expression of the ORF1 protein and its splice variant ORF1/1 in cell culture was detected by an ORF1-specific antiserum. Kakkola et al. (2008) expressed the six ORFs of TV genotype 6, in bacteria and insect cells. The expression of the ORF1/1-encoded protein was inefficient, while expression of the others was successful, with ORF1 and ORF1/2 as arginine-rich region depleted. Huang et al. (2011) expressed the ORF1 of porcine TTV species Torque teno sus virus 2 (TTSuV2) in E. coli, solubilized and purified the originally insoluble product, and used it for the development of Western blot and indirect ELISA to detect TTSuV2-specific IgG antibodies in pig sera. All studies did not touch the appearance of the putative VLPs.
Viruses
Published in Loretta A. Cormier, Pauline E. Jolly, The Primate Zoonoses, 2017
Loretta A. Cormier, Pauline E. Jolly
Alphatorquevirus is a recently discovered genus in the recently established family of Anelloviridae which includes the torque teno virus (TTV) species (Kekarainen and Segalés 2012). TTV viruses have been identified in dogs, cats, nonhuman primates, and wild and domesticated swine (Ssemadaali et al. 2016). TTV is a ubiquitous virus, found in water and sewage, in the air, and on surfaces; infection occurs in all major organs, secretions, excretions, and the blood (Ssemadaali et al. 2016). TTV has a high prevalence in the human population, is typically asymptomatic, and may be a commensal (Béland et al. 2014). In one study of 205 Japanese children aged 1–12, over 98% were positive at two years of age (Ninomiya et al. 2008). However, TTV can be an opportunistic co-infection with a variety of afflictions, including viral hepatitis, asthma, autoimmune disorders, and respiratory illnesses (Ssemadaali et al. 2016). It has also been associated with post-trans-fusion and organ transplant infections (Béland et al. 2014). Two additional Alphatorqueviruses have been identified in humans: TTMV (torque teno mini virus) and TTMDV (torque teno midi virus) (Ninomiya et al. 2009). Wild and domesticated pigs are frequently infected with TTVSuV (torque teno sus virus), which has been transmitted zoonotically to humans through contact with pork products (Ssemadaali et al. 2016).
Viral-Induced Asthma and Chronic Obstructive Pulmonary Disease
Published in Sunit K. Singh, Human Respiratory Viral Infections, 2014
Although RVs emerge as the most common type, many different viruses may be involved in exacerbations of asthma and COPD. Thus, besides RV, RSV, coronavirus, influenza, parainfluenza, human metapneumovirus, human bocaviruses, and torque teno virus have been associated with the deterioration of either or both of the obstructive lung diseases (reviewed in References 9 and 24). HIV infection has been strongly associated with the worsening of COPD.35 There are likely many more important associations between viral infections and obstructive bronchial diseases to discover. Further, we need to learn more about the relative pathogenicity of the viral infection per se compared to the inflammation that the defense responses,36 variably mounted by the host, will evoke in exacerbation-prone individuals. Akin to this issue is the possibility that respiratory tract viral infections merely appear to be more severe because disease processes of asthma and COPD have changed the baseline.
Recent Advances and Ongoing Challenges in the Diagnosis of Culture Negative Endophthalmitis
Published in Seminars in Ophthalmology, 2023
Poonam Naik, Jaishree Gandhi, Joveeta Joseph
Torque teno virus (TTV), and TTV-like mini virus (TLMV) are human anelloviruses, which are characterized by their prevalence worldwide, with literature having contradictory opinions on their pathogenic role.24 Using RT-qPCR, the presence of TTV was detected in 63.4% of culture-negative vitreous samples in addition to culture-positive and non-infectious controls. Additionally, significantly higher repeat antibiotic injections were observed in patients who were TTV and /or TLMV positive, however significant correlation was not found in case of culture-negative cases. Lee and his colleagues (2014) evaluated 21 cases (11 culture positive and 10 culture negative) of endophthalmitis postoperatively using 16S metagenomics and BRiSK and found the presence of TTV in culture-negative specimens only.25 They also suggested that the presence of TTV in the vitreous, indicates breakdown of the blood-retinal barrier due to endophthalmitis, thereby allowing TTV to enter the eye from the serum, or it could just be a marker of fulminant inflammation or bystander during leukocytic infiltration. In comparison, our results found this virus was found in non-infectious controls as well, indicating a possible stratification of TTV in the Indian population. Altogether, this study provides a novel insight into the prevalence and intra-host transmission of TTV in culture-negative endophthalmitis.24
Quantification of torque teno virus (TTV) DNA in saliva and plasma samples in patients at short time before and after kidney transplantation
Published in Journal of Oral Microbiology, 2022
Alexandre Mendes Batista, Matheus W. Caetano, Maria A. Stincarelli, Ana C. Mamana, Rodrigo Melim Zerbinati, Dmitry J. S. Sarmento, Marina Gallottini, Rafael A. V. Caixeta, José Medina-Pestana, Bengt Hasséus, Louise Zanella, Tania R. Tozetto-Mendoza, Simone Giannecchini, Paulo H. Braz-Silva
Solid organ transplantation (SOT) is the best treatment option in patients with end-stage renal failure, presenting several advantages in comparison with dialysis [1]. SOT recipients are submitted to different immunosuppressive therapy regimens to avoid organ rejection, which increases the risk of infections [2]. Thus, the paucity of consistent markers for evaluating the status of immune function in SOT recipients remains a main concern [2]. The level of immunosuppressive treatment has to be balanced between rejection and opportunistic infections, which may occur in solid organ transplantation recipients [2]. Increasing evidence has suggested that measuring the torque teno virus (TTV) load after immunosuppressive treatment may be a useful tool to evaluate the efficacy of immunosuppression [3,4].
Predictive tools to determine risk of infection in kidney transplant recipients
Published in Expert Review of Anti-infective Therapy, 2020
Mario Fernández-Ruiz, Francisco López-Medrano, José María Aguado
First isolated in 1997, torque teno virus (TTV) belongs to the genus Alphatorquevirus within the Anelloviridae family. Anelloviruses are small, non-enveloped, single-stranded DNA viruses which account for about 70% of human blood virome. TTV prevalence exceeds 70–80% in the general population of most developed and developing countries. Anelloviruses exhibit a high degree of genetic heterogeneity, similar to that observed among RNA viruses. Originally thought to cause hepatitis, TTV is currently considered an orphan virus [97]. Although TTV replication has been associated with various pro-inflammatory conditions, such as sepsis [98], cancer [99] or chronic pulmonary diseases [100], higher viremia levels are found in immunocompromised populations such as allogeneic hematopoietic stem-cell transplant recipients [101], HIV patients (with an inverse correlation with CD4+ T-cell counts) [102], or those with primary immunodeficiencies [103] or receiving biological therapies [104]. The plausibility and feasibility of monitoring TTV DNAemia to assess post-transplant immunocompetence are supported by the fact that viral replication is not influenced by the administration of valganciclovir prophylaxis and by the recent introduction of commercial real-time PCR assays targeting a highly conserved segment of the 5ʹ untranslated region of the viral genome [105].