Study of transactivating effect of pre-S2 protein of hepatitis B virus and cloning of genes transactivated by pre-S2 protein with suppression subtractive hybridization

A Rapid Immunochromatographic Method Based on a Secondary Antibody-Labelled Magnetic Nanoprobe for the Detection of Hepatitis B preS2 Surface Antigen

Hepatitis B is a globally prevalent viral infectious disease caused by the hepatitis B virus (HBV). In this study, an immunochromatographic assay (ICA) for the rapid detection of hepatitis B preS2 antigen (preS2Ag) was established. The magnetic nanoparticles (MNPs) indirectly labelled with goat anti-mouse (GAM) secondary antibody were applied as a nanoprobe for free preS2 antibody (preS2Ab) capturing and signal amplification. By employing sample pre-incubation processing as well, preS2Ag-preS2Ab was sufficiently caught by the GAM-MNPs probe in 5 min. A qualitative sensitivity of 625 ng/mL was obtained by naked-eye observation within 15-20 min. A standard curve (0-5000 ng/mL) was established, with a quantitative limit of detection (LOD) of 3.6 ng/mL, based on the stability and penetrability of the magnetic signal characteristics. The proposed method for preS2Ag was rapid (~25 min, cf. ELISA ~4 h) and had a good accuracy, which was verified using an ELISA kit (relative error < 15%). Large equipment and skilled technicians were not required. The sensitivity and specificity of the developed GAM-MNPs-ICA method were 93.3% and 90% in clinical serum samples (n = 25), respectively. A good detection consistency (84%) was observed between the developed ICA method and 2 types of commercial ELISA kits, indicating that the GAM-MNPs-ICA has a potential application in large-scale screening for and point-of-care diagnosis of hepatitis B or other infectious diseases.

Suppression subtraction hybridization (SSH) and macroarray techniques reveal differential gene expression profiles in brain of sea bream infected with nodavirus

Despite of the impact that viruses have on aquatic organisms, relatively little is known on how fish fight against these infections. In this work, the brain gene expression pattern of sea bream (Sparus aurata) in response to nodavirus infection was investigated. We used the suppression subtractive hybridization (SSH) method to generate a subtracted cDNA library enriched with gene transcripts differentially expressed after 1 day post-infection. Some of the ESTs from the infected tissues fell in gene categories related to stress and immune responses. For the reverse library (ESTs expressed in controls compared with infected tissues) the most abundant transcripts were of ribosomal and mitochondrial nature. Several ESTs potentially induced by virus exposure were selected for in vivo expression studies. We observed a clear difference in expression between infected and control samples for two candidate genes, ubiquitin conjugating enzyme 7 interacting protein, which seems to play an important role in apoptosis and the interferon induced protein with helicase C domain 1 (mda-5) that contributes to apoptosis and regulates the type I IFN production, a key molecule of the antiviral innate response in most organisms.