Establishment of a novel two-probe real-time PCR for simultaneously quantification of hepatitis B virus DNA and distinguishing genotype B from non-B genotypes

Detection technology and clinical applications of serum viral products of hepatitis B virus infection

Viral hepatitis, caused by its etiology, hepatitis virus, is a public health problem globally. Among all infections caused by hepatitis-associated viruses, hepatitis B virus (HBV) infection remains the most serious medical concern. HBV infection particularly affects people in East Asia and Africa, the Mediterranean region, and Eastern Europe, with a prevalence rate of > 2%. Currently, approximately 1 billion people worldwide are infected with HBV, and nearly 30% of them experience chronic infection. Chronic HBV infection can lead to chronic hepatitis B (CHB), liver cirrhosis, and hepatocellular carcinoma (HCC), resulting in the related death of approximately 1 million people annually. Although preventative vaccines and antiviral therapies are currently available, there is no cure for this infection. Clinical testing is not only the gateway for diagnosis of HBV infection, but also crucial for judging the timing of medication, evaluating the effect of antiviral therapy, and predicting the risk of relapse after drug withdrawal in the whole follow-up management of hepatitis B infected persons. With advances in detection technology, it is now possible to measure various viral components in the blood to assess the clinical status of HBV infection. Serum viral products of HBV infection, such as HBV DNA, HBV RNA, hepatitis B surface antigen, hepatitis B e-antigen, and hepatitis B core-related antigen, are non-invasive indicators that are critical for the rapid diagnosis and management of related diseases. Improving the sensitivity of monitoring of these products is essential, and the development of corresponding detection technologies is pivotal in achieving this goal. This review aims to offer valuable insights into CHB infection and references for its effective treatment. We provide a comprehensive and systematic overview of classical and novel methods for detecting HBV serum viral products and discusses their clinical applications, along with the latest research progress in this field.

Establishment of Coamplification at Lower Denaturation Temperature PCR/Fluorescence Melting Curve Analysis for Quantitative Detection of Hepatitis B Virus DNA, Genotype, and Reverse Transcriptase Mutation and Its Application in Diagnosis of Chronic Hepatitis B

Dynamic and real-time hepatitis B virus (HBV) DNA, genotype, and reverse transcriptase mutation analysis plays an important role in diagnosing and monitoring chronic hepatitis B (CHB) and in assessing the therapeutic response. We established a highly sensitive coamplification at lower denaturation temperature PCR (COLD-PCR) coupled with probe-based fluorescence melting curve analysis (FMCA) for precision diagnosis of CHB patients. The imprecision with %CV and detection limit of HBV DNA detected by COLD-PCR/FMCA were 2.58% to 4.42% and 500 IU/mL, respectively. For mutation, the imprecision and detection limit were 3.35% to 6.49% and 1%, respectively. Compared with Sanger sequencing, the coincidence rates of genotype and mutation were 96.0% and 82.5%, respectively, whereas the inconsistent data resulted from a low proportion (<20%) of mixed genotypes or mixed mutations. The mutation ratio in HBV infection patients was as follows: hepatitis B e antigen (HBeAg)-positive infection (0/0.0%) < HBeAg-negative infection (16/4.5%) < HBeAg-positive hepatitis (30/5.5%) < HBeAg-negative hepatitis (36/6.5%). In patients with entecavir therapy, the proportion of mutation at baseline or week 4 in virologic response (VR) group was <4%, whereas in the partial VR group, it was mostly ≥4%. COLD-PCR/FMCA provides a novel tool with high sensitivity, convenience, and practicability for the simultaneous quantification of HBV DNA, genotype, and mutation. It might be used for distinguishing the different phases of HBV infection and predicting VR of CHB patients.

Sequence-encoded quantitative invader assay enables highly sensitive hepatitis B virus DNA quantification in a single tube without the use of a calibration curve

Absolute quantification of HBV-DNA by sequence-encoded Quantitative Invader assay in a single tube without using calibration curves.

Usefulness of in-house real time PCR for HBV DNA quantification in serum and oral fluid samples

For quantification of hepatitis B virus DNA (HBV DNA), commercial assays are used with serum or plasma samples, but oral fluid samples could be an alternative for HBV diagnosis due to ease of collection. This study aims to develop in-house real time PCR using synthetic curve for HBV DNA quantification for serum and oral fluid samples. Samples were collected from 103 individuals (55 HBsAg reactive and HBV DNA reactive by commercial assay and 48 without HBV markers) and submitted to two in-house real time PCR assays for HBV pre-S/S region with different standard curves: qPCR plasmidial and qPCR synthetic. A total of 27 serum samples were HBV DNA positive by qPCR plasmidial and 40 with qPCR synthetic (72% and 85% of concordance, respectively). Quantitative PCR synthetic presented efficiency of 99% and sensitivity of 2log10 copies/mL. Among oral fluid samples, five and ten were detected using qPCR plasmidial and synthetic, respectively. This study demonstrated that qPCR synthetic using serum samples could be used as alternative for HBV DNA quantification due to its sensitivity. In addition, it was possible to quantify HBV DNA in oral fluid samples suggesting the potential of this specimen for molecular diagnosis of HBV.

A novel method to produce armored double-stranded DNA by encapsulation of MS2 viral capsids

With the rapid development of molecular diagnostic techniques, there is a growing need for quality controls and standards with favorable properties to monitor the entire detection process. In this study, we describe a novel method to produce armored hepatitis B virus (HBV) and human papillomavirus (HPV) DNA for use in nucleic acid tests, which was confirmed to be stable, homogeneous, noninfectious, nuclease resistant, and safe for shipping. We demonstrated that MS2 bacteriophage could successfully package double-stranded DNA of 1.3-, 3-, 3.5-, and 6.5-kb length into viral capsids with high reassembly efficiency. This is the first application of RNA bacteriophage MS2 as a platform to encapsulate double-stranded DNA, forming virus-like particles (VLPs) which were indistinguishable from native MS2 capsids in size and morphology. Moreover, by analyzing the interaction mechanism of pac site and the MS2 coat protein (CP), we found that in addition to the recognized initiation signal TR-RNA, TR-DNA can also trigger spontaneous reassembly of CP dimers, providing a more convenient and feasible method of assembly. In conclusion, this straightforward and reliable manufacturing approach makes armored DNA an ideal control and standard for use in clinical laboratory tests and diagnostics, possessing prospects for broad application, especially providing a new platform for the production of quality controls for DNA viruses.