Cell-free synthesis of functional antibody fragments to provide a structural basis for antibody–antigen interaction

<div><p>Growing numbers of therapeutic antibodies offer excellent treatment strategies for many diseases. Elucidation of the interaction between a potential therapeutic antibody and its target protein by structural analysis reveals the mechanism of action and offers useful information for developing rational antibody designs for improved affinity. Here, we developed a rapid, high-yield cell-free system using dialysis mode to synthesize antibody fragments for the structural analysis of antibody–antigen complexes. Optimal synthesis conditions of fragments (Fv and Fab) of the anti-EGFR antibody 059–152 were rapidly determined in a day by using a 30-μl-scale unit. The concentration of supplemented disulfide isomerase, DsbC, was critical to obtaining soluble antibody fragments. The optimal conditions were directly applicable to a 9-ml-scale reaction, with linear scalable yields of more than 1 mg/ml. Analyses of purified 059-152-Fv and Fab showed that the cell-free synthesized antibody fragments were disulfide-bridged, with antigen binding activity comparable to that of clinical antibodies. Examination of the crystal structure of cell-free synthesized 059-152-Fv in complex with the extracellular domain of human EGFR revealed that the epitope of 059-152-Fv broadly covers the EGF binding surface on domain III, including residues that formed critical hydrogen bonds with EGF (Asp355^EGFR, Gln384^EGFR, H409^EGFR, and Lys465^EGFR), so that the antibody inhibited EGFR activation. We further demonstrated the application of the cell-free system to site-specific integration of non-natural amino acids for antibody engineering, which would expand the availability of therapeutic antibodies based on structural information and rational design. This cell-free system could be an ideal antibody-fragment production platform for functional and structural analysis of potential therapeutic antibodies and for engineered antibody development.</p></div

Clinical Outcomes of Digital Cholangioscopy-Guided Procedures for the Diagnosis of Biliary Strictures and Treatment of Difficult Bile Duct Stones: A Single-Center Large Cohort Study

Although Spy DS (SpyGlass DS Direct Visualization System) is considered to be useful for the diagnosis of bile duct strictures and the treatment of bile duct stones, there is limited data to date validating its efficacy. We hence retrospectively evaluated the clinical outcomes of the use of Spy DS in a large number of patients. A total of 183 patients who underwent Spy DS-guided procedures for indeterminate bile duct strictures (n = 93) and bile duct stones (n = 90) were analyzed retrospectively. All patients (93/93) with bile duct strictures successfully underwent visual observation, and 95.7% (89/93) of these patients successfully underwent direct biopsy. The sensitivity, specificity, and overall accuracy were 94.7%, 83.3%, and 90.3%, respectively, for visual impression; 80.9%, 100%, and 89.2%, respectively, for histopathological analysis of a direct biopsy; and 96.5%, 91.7%, and 94.6%, respectively, for visual impression combined with biopsy. Successful visualization of the stones was achieved in 98.9% (89/90) of the patients, and complete stone removal was achieved in 92.2% (83/90) of the patients, with an average of 3.3 procedures. The adverse events rate was 17.5% (32/183; cholangitis in 15 patients, fever the following day in 25, pancreatitis in 1, hemorrhage in 1, and gastrointestinal perforation in 1). No administration of antibiotics before the procedure was found to be a statistically significant risk factor for the development of fever after the procedure (p &lt; 0.01). Spy DS-guided procedures are effective for the diagnosis and treatment of bile duct lesions and can be performed with a low risk of serious adverse events

SDS-PAGE analysis of cell-free synthesized 059-152-Fv and 059-152-Fab.

<p>(A) 059-152-Fv was synthesized under a series of different concentrations (0, 0.2, and 0.4 mg/ml) of DsbC, as indicated. Total (T) and soluble (S) fractions of the internal solution were analyzed by reducing SDS-PAGE. (B) Purified 059-152-Fv was analyzed by reducing and non-reducing SDS-PAGE. The yields (mg per 1 ml internal solution) of partially purified Fv are indicated under each lane of the non-reducing SDS polyacrylamide gel image. (C) 059-152-Fab was synthesized in the presence of 0, 0.2, 0.4, and 0.8 mg/ml of DsbC, as indicated. (D) Purified 059-152-Fab was analyzed by reducing and non-reducing SDS-PAGE. The yields (mg per 1 ml internal solution) of partially purified Fab are indicated under each lane of the non-reducing SDS polyacrylamide gel image. BG: cell-free synthesis without template DNA. VH: cell-free synthesis of VH without DsbC. VL: cell-free synthesis of VL without DsbC. VHCH1: cell-free synthesis of VHCH1 without DsbC. L chain: cell-free synthesis of light chain without DsbC. Gels were stained with CBB.</p

SDS-PAGE analysis of site-specific fluorescent-labeled 059-152-Fv and 059-152-Fab.

<p>Reducing and non-reducing SDS-PAGE analysis of 059-152-Fv (A) and 059-152-Fab (B). (lane 1) 059-152-Fv, (lane 2) AzF-incorporated 059-152-Fv, (lane 3) Alexa-488 conjugated 059-152-Fv, (lane 4) 059-152-Fab, (lane 5) AzF-incorporated 059-152-Fab, and (lane 6) Alexa-488 conjugated 059-152-Fab. Fluorescent images and CBB-stained images were acquired from the same gels.</p

Additional file 1: Table S1. of Long-term efficacy and safety of fingolimod in Japanese patients with relapsing multiple sclerosis: 3-year results of the phase 2 extension study

Duration of exposure to fingolimod in patients entering the extension study. Table S2. Plasma levels of liver enzymes at core study baseline and in the extension study. Table S3. Proportion of patients with normal and elevated levels of liver enzymes. Table S4. Proportion of patients with normal and decreased levels of hematological parameters. (DOCX 35 kb