Detection of hepatitis B virus DNA in serum using synthetic non-radioactive oligonucleotides

Evaluation of enzyme immunoassay for hepatitis B virus DNA based on anti-double-stranded DNA

We have evaluated a new enzyme immunoassay technology to detect the products of PCR-based amplification that may be applicable to routine testing of hepatitis B virus (HBV) DNA. Two hundred eight serum samples were studied: 73 were basal samples and 135 were sequential serum samples from patients with chronic hepatitis, some of whom were being treated with alpha interferon. We compared the new detection method (PCR-DNA enzyme immunoassay [DEIA]) with dot blot hybridization performed without prior PCR amplification and with two other methods for detection of PCR products: agarose gel electrophoresis with ethidium bromide staining (PCR-EB) and dot blot (PCR-dot blot). For hepatitis B-antigen-positive basal samples, HBV DNA was detected in 70.4% by dot blot, 74.1% by PCR-EB, and 100% by PCR-DEIA and PCR-dot blot; for anti-hepatitis B e-antigen basal samples, HBV DNA was found in 10.5% by dot blot and PCR-EB and in 42.1% by PCR-DEIA and PCR-dot blot. Chi-square tests showed a strong association between dot blot and PCR-EB and between PCR-DEIA and PCR dot blot. Using PCR-dot blot as the reference, dot blot shows a 56.9% sensitivity and a 100% specificity, PCR-EB shows a 55.0% sensitivity and a 100% specificity, and PCR-DEIA shows a 95.4% sensitivity and a 97% specificity. We conclude that the technical advantages of the DEIA method and its high sensitivity and specificity may facilitate the use of PCR in routine testing for HBV DNA in clinical microbiology laboratories.

Quantitative detection of hepatitis B virus DNA in serum using chemiluminescence: comparison with radioactive solution hybridization assay

A quantitative, non-radioactive hybrid capture HBV DNA assay (Digene Diagnostics), which uses an efficient solution hybridization procedure coupled to a sensitive chemiluminescent signal amplification system, was compared with the quantitative, radioactive solution hybridization assay (Genostics, Abbott Laboratories), in hepatitis B virus carriers, particularly in those undergoing antiviral therapy. The qualitative reproducibility of the chemiluminescent method, tested on 30 sera, was acceptable, with a reproducibility rate of 93.3%. A comparison of this hybrid capture HBV DNA assay with the radioactive test on 113 sera obtained from 48 patients (39 HBsAg-positive patients) gave a sensitivity of 87.2%, a specificity of 100% and an agreement between the two tests of 89.4% (101 sera including 82 HBV DNA positive and 19 negative samples). Changes in HBV DNA levels measured by the two assays showed a good correlation with each other during interferon therapy. However, the hybrid capture values were higher than the radioactive assay values, with the ratio of the two values being variable in the same patient during the course of treatment. The Genostics assay therefore seems to be a more accurate procedure for evaluating changes in viral replication, particularly at high HBV DNA levels. However, the hybrid capture method is faster and has the advantage of being a non-radioactive procedure. This chemiluminescent assay is easy to perform as a routine diagnostic procedure and may be a useful alternative to the radioactive solution hybridization method.

Detection of human papillomavirus DNA and mRNA using synthetic, type-specific oligonucleotide probes

Type-specific 30'mer-36'mer oligonucleotide probes complementary to mRNA transcribed from the E6 and E7 open reading frames of HPV 6b/11, 16, 18 and 33 were designed using the published nucleotide sequences. As oligonucleotides are easily and relatively cheaply synthesized in large amounts and are free of vector DNA, they were assessed for potential use in routine clinical detection and typing of HPV. Multiple Southern and dot blots of cloned HPV 6b, 11, 16, 18, 31 and 33 DNA, and of DNA extracted from cell lines carrying integrated HPV 16 and 18 genomes were prepared. In addition, Northern and dot blots of RNA extracted from the HPV-containing cell lines HeLa, CaSki and SiHa, were also prepared. All filters were first probed with the oligonucleotide and then with the corresponding full-genomic HPV DNA probe and their relative sensitivities and specificities compared: both probe types were labelled with 32P. The oligonucleotide probes were all as specific as the full-genomic probes for Southern, DNA and RNA dot blot hybridisations. The HPV 16 and 18 oligonucleotide probes detected HPV transcripts of the appropriate sizes in the cell line RNA. For DNA detection, oligonucleotide probes were up to 10 times less sensitive than the full-genomic probes, but for RNA detection, they were more sensitive. The sensitivity for both HPV DNA and RNA detection could be improved by using two type-specific oligonucleotide probes in combination, without reducing the specificity. The ease of preparation and handling of oligonucleotide probes, together with their lack of contaminating vector DNA, suggests that they may have some advantages over full-genomic probes for the clinical detection and typing of HPV.

An enzyme-linked (alkaline phosphatase) oligonucleotide probe for the detection of serum hepatitis B virus DNA

Serum HBV-DNA detection represents a new and important diagnostic tool for the hepatologist, as well as a prognostic and therapeutic guide. Though most laboratories use genomic radioactive probes, the appearance of commercially available enzyme-linked oligonucleotide probes, which simplify the method, represents an advance in HBV-DNA detection. In order to verify the value of an enzyme-linked (alkaline phosphatase) oligonucleotide probe in HBV-DNA detection, we have first compared the results of the detection of serum HBV-DNA in 46 patients at different serological stages of HBV infection using this probe and with those obtained using a genomic P32-labeled probe. Fisher's test analysis of the results shows statistical significance; this indicates a high correlation between methods. Secondly, we have tested 296 sera of patients at different serological stages of HBV infection with the enzyme-linked probe; we have found HBV-DNA in 8 patients with acute hepatitis (61.54%), 61 HBeAg (70.12%), and 7 anti-HBe (12.07%) chronic hepatitis. These results show the value of this probe for routine survey of serum HBV-DNA using a simple method which avoids the use of radioactivity.

A single-step DNA extraction procedure for the detection of serum hepatitis B virus sequences by the polymerase chain reaction

A rapid single-step procedure for the isolation of low molecular weight DNA using guanidinium thiocyanate and phenol as protein denaturants is described and applied for the detection of specific hepatitis B virus (HBV) DNA sequences from serum samples by the polymerase chain reaction (PCR). The novel technique is efficient and, when compared to the standard proteinase K/phenol/chloroform method has the advantage of being faster and easily adaptable to the routine processing of a high number of clinical samples by PCR and spot hybridization techniques.