Torquetenovirus detection in exosomes enriched vesicles circulating in human plasma samples

Area of Science:

• Virology
• Cell Biology
• Immunology

Background:

• Torquetenovirus (TTV) establishes lifelong infections in humans without apparent disease.
• Viruses are increasingly found to utilize host extracellular vesicles (EVs) for persistence.
• This study investigates the presence of TTV within circulating EVs in human plasma.

Purpose of the Study:

• To determine if Torquetenovirus (TTV) is present in extracellular vesicles (EVs) found in human plasma.
• To characterize the EVs containing TTV and quantify viral load within them.
• To explore potential mechanisms of TTV persistence facilitated by EVs.

Main Methods:

• Extraction and characterization of exosomes enriched vesicles (EEVs) from human plasma using nanoparticle tracking analysis, western blot, and electron microscopy.
• Quantification of TTV DNA in plasma and EEVs via single-step real-time TaqMan PCR.
• Analysis of TTV DNA in EEVs from diverse patient cohorts, including HIV, HCV, HBV, and kidney transplant recipients.

Main Results:

• Plasma-derived EVs (70nm size, 2.5×10^9/ml concentration) tested positive for exosomal markers (CD63, CD81, annexin II).
• TTV DNA was detected in EEVs (6.3×10^2 copies/ml) and varied with sample treatment.
• TTV DNA was found in 34% of plasma EEV samples from 122 individuals, with genogroup 3 being prevalent.

Conclusions:

• Circulating TTV particles are associated with extracellular vesicles in human plasma.
• EV-mediated circulation offers a potential mechanism for anellovirus persistence and host interaction.
• Further research is warranted to elucidate the precise role of EVs in TTV infection dynamics.