Effective Construction of a High-Capacity Boronic Acid Layer on a Quartz Crystal Microbalance Chip for High-Density Antibody Immobilization

Boronic acids (BAs) provide strong potential in orientation immobilization of antibody and the modification method is crucial for efficiency optimization. A highly effective method has been developed for rapid antibody immobilization on gold electrodes through the electrodeposition of a BA–containing linker in this study. Aniline-based BA forms a condense layer while antibody could automatically immobilize on the surface of the electrode. Compare to traditional self-assembled monolayer method, the electrodeposition process dramatically reduces the modification time from days to seconds. It also enhances the immobilized efficiency from 95 to 408 (ng/cm2) with a strong preference being exhibited for shorter aniline-based linkers

Characterization and epitope mapping of Dengue virus type 1 specific monoclonal antibodies

Abstract Background Dengue virus (DV) infection causes a spectrum of clinical diseases ranging from dengue fever to a life-threatening dengue hemorrhagic fever. Four distinct serotypes (DV1–4), which have similar genome sequences and envelope protein (E protein) antigenic properties, were divided. Among these 4 serotypes, DV1 usually causes predominant infections and fast diagnosis and effective treatments are urgently required to prevent further hospitalization and casualties. Methods To develop antibodies specifically targeting and neutralizing DV1, we immunized mice with UV-inactivated DV1 viral particles and recombinant DV1 E protein from residue 1 to 395 (E395), and then generated 12 anti-E monoclonal antibodies (mAbs) as the candidates for a series of characterized assays such as ELISA, dot blot, immunofluorescence assay, western blot, and foci forming analyses. Results Among the mAbs, 10 out of 12 showed cross-reactivity to four DV serotypes as well as Japanese encephalitis virus (JEV) in different cross-reactivity patterns. Two particular mAbs, DV1-E1 and DV1-E2, exhibited strong binding specificity and neutralizing activity against DV1 and showed no cross-reactivity to DV2, DV3, DV4 or JEV-infected cells as characterized by ELISA, dot blot, immunofluorescence assay, western blot, and foci forming analyses. Using peptide coated indirect ELISA, we localized the neutralizing determinants of the strongly inhibitory mAbs to a sequence-unique epitope on the later-ridge of domain III of the DV1 E protein, centered near residues T346 and D360 (346TQNGRLITANPIVTD360). Interestingly, the amino acid sequence of the epitope region is highly conserved among different genotypes of DV1 but diverse from DV2, DV3, DV4 serotypes and other flaviviruses. Conclusions Our results showed two selected mAbs DV1-E1 and DV1-E2 can specifically target and significantly neutralize DV1. With further research these two mAbs might be applied in the development of DV1 specific serologic diagnosis and used as a feasible treatment option for DV1 infection. The identification of DV1 mAbs epitope with key residues can also provide vital information for vaccine design

Quinazolinone-Peptido-Nitrophenyl-Derivatives as Potential Inhibitors of SARS-CoV-2 Main Protease

The severe acute respiratory syndrome coronavirus 2 main protease (SARS-CoV-2-Mpro) plays an essential role in viral replication, transcription, maturation, and entry into host cells. Furthermore, its cleavage specificity for viruses, but not humans, makes it a promising drug target for the treatment of coronavirus disease 2019 (COVID-19). In this study, a fragment-based strategy including potential antiviral quinazolinone moiety and glutamine- or glutamate-derived peptidomimetic backbone and positioned nitro functional groups was used to synthesize putative Mpro inhibitors. Two compounds, G1 and G4, exhibited anti-Mpro enzymatic activity in a dose-dependent manner, with the calculated IC50 values of 22.47 ± 8.93 μM and 24.04 ± 0.67 μM, respectively. The bio-layer interferometer measured real-time binding. The dissociation kinetics of G1/Mpro and G4/Mpro also showed similar equilibrium dissociation constants (KD) of 2.60 × 10−5 M and 2.55 × 10−5 M, respectively, but exhibited distinct association/dissociation curves. Molecular docking of the two compounds revealed a similar binding cavity to the well-known Mpro inhibitor GC376, supporting a structure−function relationship. These findings may open a new avenue for developing new scaffolds for Mpro inhibition and advance anti-coronavirus drug research

Quinazolinone-Peptido-Nitrophenyl-Derivatives as Potential Inhibitors of SARS-CoV-2 Main Protease

The severe acute respiratory syndrome coronavirus 2 main protease (SARS-CoV-2-Mpro) plays an essential role in viral replication, transcription, maturation, and entry into host cells. Furthermore, its cleavage specificity for viruses, but not humans, makes it a promising drug target for the treatment of coronavirus disease 2019 (COVID-19). In this study, a fragment-based strategy including potential antiviral quinazolinone moiety and glutamine- or glutamate-derived peptidomimetic backbone and positioned nitro functional groups was used to synthesize putative Mpro inhibitors. Two compounds, G1 and G4, exhibited anti-Mpro enzymatic activity in a dose-dependent manner, with the calculated IC50 values of 22.47 ± 8.93 μM and 24.04 ± 0.67 μM, respectively. The bio-layer interferometer measured real-time binding. The dissociation kinetics of G1/Mpro and G4/Mpro also showed similar equilibrium dissociation constants (KD) of 2.60 × 10−5 M and 2.55 × 10−5 M, respectively, but exhibited distinct association/dissociation curves. Molecular docking of the two compounds revealed a similar binding cavity to the well-known Mpro inhibitor GC376, supporting a structure−function relationship. These findings may open a new avenue for developing new scaffolds for Mpro inhibition and advance anti-coronavirus drug research

The thermostable direct hemolysin from Grimontia hollisae causes acute hepatotoxicity in vitro and in vivo.

BACKGROUND: G. hollisae thermostable direct hemolysin (Gh-TDH) is produced by most strains of G. hollisae. This toxin has been reported to be absorbed in the intestines in humans. Secondary liver injury might be caused by venous return of the toxin through the portal system. We aimed to firstly analyze the in vitro and in vivo hepatotoxicity of Gh-TDH. METHODS: Liver cells (primary human non-cancer cell and FL83B mouse cells) were treated and mice (BALB/c) were fed with this toxin to investigate its hepatotoxicity. Morphological examination and cytotoxicity assays using liver cells were also performed. Fluorescein isothiocyanate-conjugated toxin was used to analyze the localization of this protein in liver cells. Mice were subjected to liver function measurements and liver biopsies following toxin treatment and wild-type bacterial infection. PET (positron emission tomography)/CT (computed tomography) images were taken to assess liver metabolism during acute injury and recovery. RESULTS: The effect of hepatotoxicity was dose and time dependent. Cellular localization showed that the toxin was initially located around the cellular margins and subsequently entered the nucleus. Liver function measurements and liver biopsies of the mice following treatment with toxin or infection with wild-type Grimontia hollisae showed elevated levels of transaminases and damage to the periportal area, respectively. The PET/CT images revealed that the reconstruction of the liver continued for at least one week after exposure to a single dose of the toxin or bacterial infection. CONCLUSIONS: The hepatotoxicity of Gh-TDH was firstly demonstrated. The damage was located in the periportal area of the liver, and the liver became functionally insufficient

Purification, crystallization and preliminary X-ray crystallographic analysis of xylose reductase from Candida tropicalis

The crystallization of xylose reductase from C. tropicalis is reported

Comparison of antiplatelet antibody profiles between hepatitis C virus-associated immune thrombocytopenia and primary immune thrombocytopenia

Hepatitis C virus-associated immune thrombocytopenia (HCV-ITP) has been assumed to be one of secondary ITP and associated with antiplatelet antibodies. This study was to clarify the antibody profile in HCV-ITP compared with primary ITP. We enrolled 55 HCV-ITP, 30 primary ITP, 11 Helicobacter pylori-ITP, 21 HCV control, and 16 healthy volunteers. We reviewed their blood cell counts, autoimmune markers, and spleen size. We used enzyme-linked immunosorbent assay kit to detect the specific antibody to glycoproteins IIb/IIIa, Ia/IIa, Ib/IX, IV, and human leukocyte antigen (HLA) class I. Compared with primary ITP patients, HCV-ITP patients had an older age, lower white blood cell (WBC) count and fewer presented with severe thrombocytopenia. The rate of positive antibody detection was 63.6% for the HCV-ITP group higher than the rate of 40% for the primary ITP. In the HCV control, antiplatelet antibodies were detected in 38.1% patients and no one had more than two types of antibodies. The antiplatelet antibodies correlated to severer thrombocytopenia. An HLA class I antibody was associated with lower WBCs and larger spleen. In conclusion, HCV-ITP patients had a high rate of positive antiplatelet antibody. The antibodies were associated with not only lower platelets but also leukopenia and splenomegaly

¹⁸F-FDG PET/CT scan.

<p>Mice were treated with 0.07 mCi ¹⁸F-FDG by tail vein injection, and imaging was performed 1 hr later. (A) All mice received 3 series of images, including CT, PET, and a merge of CT and PET. The location of the liver is labeled by a dotted line where the cross-sectioned images were obtained. (B) These images are cross-sections of the livers. At 8, 72 and 168 hr after treatment with Gh-rTDH, the uptake of ¹⁸F-FDG in livers decreased in proportion to the dosage of Gh-rTDH. (C) The ¹⁸F-FDG uptake value was calculated using the ROI (liver/muscle, semi-quantification) in each mouse. Higher doses of toxin indicated lower levels of ¹⁸F-FDG uptake. In the animal infection models, the ¹⁸F-FDG uptake levels were clearly lower in mice that were fed (D) <i>G. hollisae</i> or (E) <i>E. coli</i>-TOPO-<i>tdh</i> than those fed (F) <i>E. coli</i>-TOPO. These decreases were in proportion to the levels of bacteria in the treatment.</p