A multiplex PCR assay able to simultaneously detect Torque teno virus isolates from phylogenetic groups 1 to 5

Abstract

Torque teno virus (TTV) is a circular, single-stranded DNA virus that chronically infects healthy individuals of all ages worldwide. TTV has an extreme genetic heterogeneity which is reflected in its current classification into five main phylogenetic groups (1-5). Using specific PCR assays, it has been shown that many individuals are co-infected with TTV isolates belonging to different phylogenetic groups. Here, a multiplex PCR assay was developed, using five recombinant plasmids. Each plasmid carried an insert of different size issued from a TTV isolate belonging to a different group. The assay was able to simultaneously amplify DNAs of TTV isolates belonging to all five phylogenetic groups. Multiplex PCR was then tested satisfactorily on DNAs extracted from 55 serum samples (47 health care workers and 8 AIDS patients). All individuals but nine were infected with at least one TTV isolate. Co-infection with multiple isolates was found in 29/ 47 (62%) health care workers and in 8/8 (100%) AIDS patients. A number of discrepancies were observed when results obtained with three thermostable DNA polymerases were compared. For example, four TTV phylogenetic groups were detected in a particular serum sample by using one of the three DNA polymerases, whereas the other two enzymes were able to detect only three TTV groups. However, none of the three enzymes used could be broadly considered to be more efficient than the others. Despite its limitations, the assay described here constitutes a suitable tool to visualize the degree of coinfection of a given population, avoiding time-consuming experiments.

Human anelloviruses and the central nervous system

“…Those currently in use are several and have different breadths and sensitivities. They can be distinguished in “universal” which amplify most if not all the human anelloviruses, in genus‐specific and, with regard to TTV alone, in genogroup‐specific 30–34. These latter PCR assays permit the genetic characterization of the TTV found in the patient under scrutiny and the satisfactory grouping of the virus in one of the 5 genogroups in which the TTV species have been subdivided (Figure 1).…”

Torque Teno Virus (TTV) distribution in healthy Russian population

“…Despite 10 years of investigation, the TTV distribution in humans is still a subject of discussion. Possibly, this is because of the variability of TTV genotypes and the inability to design a single set of PCR primers, corresponding to the vast majority (if not all) viral genotypes [ 20 ]. Also little is known about distribution of TTV in healthy adults [ 21 , 22 ].…”