A Peptide-based Magnetic Chemiluminescence Enzyme Immunoassay for Serological Diagnosis of Corona Virus Disease 2019 (COVID-19)

A respiratory illness has been spreading rapidly in China, since its outbreak in Wuhan city, Hubei province in December 2019. The illness was caused by a novel coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Clinical manifestations related to SARS-CoV-2 infection ranged from no symptom to fatal pneumonia. World Health Organization (WHO) named the diseases associated with SARS-CoV-2 infection as COVID-19. Real time RT-PCR is the only laboratory test available till now to confirm the infection. However, the accuracy of real time RT-PCR depends on many factors, including sampling location and of methods, quality of RNA extraction and training of operators etc.. Variations in these factors might significantly lower the sensitivity of the detection. We developed a peptide-based luminescent immunoassay to detect IgG and IgM. Cut-off value of this assay was determined by the detection of 200 healthy sera and 167 sera from patients infected with other pathogens than SARS-CoV-2. To evaluate the performance of this assay, we detected IgG and IgM in the 276 sera from confirmed patients. The positive rate of IgG and IgM were 71.4% (197/276) and 57.2% (158/276) respectively. By combining with real time RT-PCR detection, this assay might help to enhance the accuracy of diagnosis of SARS-CoV-2 infection.

Screening and identification of polypeptides targeting hepatitis B virus HBP-TP protein / 中华微生物学和免疫学杂志

Objective To identify specific peptides binding to hepatitis B virus ( HBV) DNA pol-ymerase TP region ( HBP-TP) and to study their effects on HBV replication. -ethods The phage polypep-tide display library was screened using the HBP-TP recombinant protein expressed in Escherichia coli as a substrate to obtain the specific phage, the polypeptide region of which was then sequenced. Polypeptide se-quences with a repetition rate greater than 10％ were counted and commercially synthesized. Changes in HBV replication were detected after treatment of HBV-expressing cells with synthetic peptides as drugs. Re-sults Eight peptides targeting HBP-TP recombinant protein were screened out from the phage display librar-y. One of the peptides was found to have a significant inhibitory effect on HBV replication at cellular level. Conclusions A HBP-TP protein-targeting polypeptide with an inhibitory effect on HBV replication was ob-tained.

Establishment of an HBV chronic hepatitis B infection mouse model by vivo transduction of HBV cccDNA / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To generate a mouse model of chronic hepatitis B (CHB) infection by performing in vivo transduction of hepatitis B virus (HBV) covalently closed circular (ccc)DNA.</p><p><b>METHODS</b>Nude mice were injected with HBV cccDNA at doses of 1.5, 1.0 or 0.5 mug/ml. A control group was generated by giving equal injection volumes of physiological saline. The serum levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) on post-injection days 1 and 3, weeks 1-6, 8 and 10 were assayed by reflection immunoassay. At post-injection week 10, all animals were sacrificed and liver tissues were collected. Copies of HBV DNA in serum and liver tissue were detected by real-time PCR. HBV antigens in liver tissue were detected of by immunohistochemistry. Pathological analysis of liver tissue carried out with hematoxylin-eosin staining. Linear correlation of data was determined by statistical analysis.</p><p><b>RESULTS</b>HBsAg and HBeAg were detected in sera from all three groups of cccDNA-injected mice staring at post-injection day 1 and lasting through week 10. The levels of HBsAg over the 10-week period showed two patterns of increase-decrease;the lowest level was detected at week 4 and the highest level was detected at week 8. In contrast, the levels of HBeAg over the 10-week period showed three patterns of increase-decrease; the lower levels were detected at weeks 2 and 4 and the higher levels at weeks 3 and 6. HBV DNA copies in liver tissues showed a cccDNA dose-dependent descending trend over the 10-week study period (1.5 mug/ml:1.14E+07 ± 6.51E+06 copies/g, 1.0 mug/ml:9.81E+06 ± 9.32E+06 copies/g, and 0.5 mug/ml:3.72E+06 ± 2.35E+06 copies/g; Pearson's r =0.979). HBV DNA copies in sera showed the pattern of 1.0 mug/ml cccDNA more than 1.5 mug/ml cccDNA more than 0.5 mug/ml cccDNA, and in general were higher than those detected in the liver tissues. Liver tissues from all cccDNA-injected mice showed positive immunohistochemistry staining for both HBsAg and HBeAg. HE staining showed that the liver tissues of all cccDNA-injected mice had severe fatty and vacuolar degeneration and less obvious structure of liver lobules (compared to the liver tissues from control mice).</p><p><b>CONCLUSION</b>The CHB mouse model successfully established in this study by in vivo transduction of HBV cccDNA may represent a useful tool to study the pathogenic mechanisms and potential antiviral treatments of human CHB.</p>

Screening of proteins interacting with hepatitis C virus core protein from T7-phage display library / 第三军医大学学报

Objective To screen and identify proteins that interact with the hepatitis C virus core protein by means of T7-phage display system. Methods The hepatitis C virus core protein was expressed by prokaryotic expression and used as selected molecule to biopan the T7 human liver cDNA library. The selected positive clones were identified by DNA sequence and analyzed with BLAST program in GenBank. Results After BLAST in all positive clones, one protein--Smad interacting protein 1 (SIP1) was found to interact with the hepatitis C virus core protein. Conclusion T7-phage display system is a convenient, rapid and effective method for screening interacting proteins.