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Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging negatively stranded enveloped RNA bunyavirus that causes SFTS with a high case fatality rate of up to 30%. Macroautophagy/autophagy is an evolutionarily conserved process involved in the maintenance of host homeostasis, which exhibits anti-viral or pro-viral responses in reaction to different viral challenges. However, the interaction between the bunyavirus SFTSV and the autophagic process is still largely unclear. By establishing various autophagy-deficient cell lines, we found that SFTSV triggered RB1CC1/FIP200-BECN1-ATG5-dependent classical autophagy flux. SFTSV nucleoprotein induced BECN1-dependent autophagy by disrupting the BECN1-BCL2 association. Importantly, SFTSV utilized autophagy for the viral life cycle, which not only assembled in autophagosomes derived from the ERGIC and Golgi complex, but also utilized autophagic vesicles for exocytosis. Taken together, our results suggest a novel virus–autophagy interaction model in which bunyavirus SFTSV induces classical autophagy flux for viral assembly and egress processes, suggesting that autophagy inhibition may be a novel therapy for treating or releasing SFTS. [ABSTRACT FROM AUTHOR]

Two types of lateral flow immunochromatographic test strips (LFITS) using gold nanoparticles and fluorescent CdTe quantum dots (QDs) as signal labels, respectively, were developed for Shiga toxin type II (STX2) assays. Under optimal conditions, the corresponding visual detection limits were 25 ng mL-1 and 5 ng mL-1, respectively. The test results of gold based LFITS can be recognized directly by the naked eye, whereas the visualized results of CdTe QDs based LFITS can be observed by the aid of a UV lamp. Both assays showed good specificity and stability. The inexpensive LFITS were promising for the rapid clinical detection of STX2.

Aim: To prepare the monoclonal antibody (mAb) against human growth differentiation factor 15 (GDF15)., Methods: The expression vector pGEX-4T-2-gdf15 was constructed and transformed into E.coli Top10F' for expression. Then the purified fusion protein was used to immunize the BALB/c mice. The mouse myeloma cells (Sp2/0) were fused with spleen cells from the BALB/c immunized by the purified protein. Subsequently, limited dilution method was used three times to screen hybridoma cell lines. The titer of the mAb was detected by ELISA and its specificity was analyzed by Western blot. The serum level of GDF15 in hepatocellular carcinoma (HCC) and health people was measured by co-immunoprecipitation (IP) method., Results: The GST-GDF15 fusion protein was successfully expressed and purified. One hybridoma cell line designated 9G3 against GDF15 was obtained. IP and mass spectrometric analysis revealed that the mAb recognized GDF15 in human sera with high specificity. The level of GDF15 in HCC patients was much higher than that in health people., Conclusion: The success in mouse anti-GDF15 mAb preparation provides the basis for further developing HCC diagnose kit.

Aim: To insert the full-length NS1 gene of influenza A (H1N1) into an eukaryotic expression vector PXJ40-HA, and to evaluate the expression of NS1 gene in transfected 293T cells., Methods: The NS1 gene of influenza A (H1N1) was amplified by RT-PCR and cloned into pMD18-T vector to construct a plasmid, named pMD18-T-NS1.The pMD18-T-NS1 and the PXJ40-HA were both digested using the same restrict enzymes and ligated, yielding the recombinant eukaryotic expression vector PXJ40-HA-NS1. The expression of the NS1 gene in transfected 293T cells was tested by Western blot., Results: The recombinant eukaryotic expression vector PXJ40-HA-NS1 was successfully constructed. The NS1 protein was observed to be expressed in 293T cells., Conclusion: The full-length NS1 gene is obtained and its recombinant eukaryotic expression plasmid is successfully constructed. This study is of help to further understanding the biological function of NS1 protein and the mechanism of diseases induced by influenza A virus.

Objective: To screen anti-c-Met Fab from a phage antibody library and identify its binding activity., Methods: The expression of c-Met of HCC lines was identified by Western blot and immunofluorescence. Antibodies against c-Met were screened with immobilized antigen. After five rounds of panning, 30 randomly selected clones were identified by phage ELISA to select specific clones with high affinity. The positive clones were selected for Fab soluble expression in TOP10F and the binding activities were analysed in HCC lines., Results: c-Met expressed in HCC membrane was confirmed by Western blot and immunofluorescence. A Fab fragment named AM2-26 with fine activity to c-Met was selected. AM2-26 binding specificity was confirmed by IP, FACS and immunofluorescence., Conclusion: The anti-c-Met Fab binding to c-Met in HCC provides a promising candidate for the biotherapy of hepatoma.