Bio-conjugation of anti-human CD3 monoclonal antibodies to magnetic nanoparticles by using cyanogen bromide: A potential for cell sorting and noninvasive diagnosis.

The conjugation of monoclonal antibodies with superparamagnetic iron oxide nanoparticles (SPIONs) has appeared as a potential multifunctional clinical tool, which can effectively diagnose cancers and monitor their treatment, specifically. Despite the presence of different methods for conjugating antibodies to iron oxide nanoparticles, novel cost-effective and simpler conjugation techniques should be performed in this regard. In current study, an anti-CD3 monoclonal antibody was conjugated to the Fe3O4 coated by carboxymethyl dextran (CMD) using cyanogen bromide (CNBr). Moreover, EDC/NHS techniques were applied as a positive control. The experimental results showed that the Conjugation was performed and the presence of the antibody conjugated to the MNPs in human xenograft tumors was confirmed using Prussian blue (PB) staining, following magnetic resonance imaging (MRI), 30 min after injection. This conjugation method was shown to be able to separate CD3+ T lymphocytes efficiently from whole blood with high purity. Accordingly, this type of bio-conjugation method can be utilized in the future for cell sorting, and can be applied for adopted cell therapies such as CAR-T cell (Chimeric antigen receptor T cell) therapy, as well as targeted MRI imaging.

Comparative studies on drug binding to the purified and pharmaceutical-grade human serum albumins: Bridging between basic research and clinical applications of albumin.

Human serum albumin (HSA), the most abundant protein in blood plasma, is a monomeric multidomain protein that possesses an extraordinary capacity for binding, so that serves as a circulating depot for endogenous and exogenous compounds. During the heat sterilization process, the structure of pharmaceutical-grade HSA may change and some of its activities may be lost. In this study, to provide deeper insight on this issue, we investigated drug-binding and some physicochemical properties of purified albumin (PA) and pharmaceutical-grade albumin (PGA) using two known drugs (indomethacin and ibuprofen). PGA displayed significantly lower drug binding capacity compared to PA. Analysis of the quenching and thermodynamic parameters indicated that intermolecular interactions between the drugs and the proteins are different from each other. Surface hydrophobicity as well as the stability of PGA decreased compared to PA, also surface hydrophobicity of PA and PGA increased upon drugs binding. Also, kinetic analysis of pseudo-esterase activities indicated that Km and Vmax parameters for PGA enzymatic activity are more and less than those of PA, respectively. This in vitro study demonstrates that the specific drug binding of PGA is significantly reduced. Such studies can act as connecting bridge between basic research discoveries and clinical applications.

Studies of the interaction between isoimperatorin and human serum albumin by multispectroscopic method: identification of possible binding site of the compound using esterase activity of the protein.

Isoimperatorin is one of the main components of Prangos ferulacea as a linear furanocoumarin and used as anti-inflammatory, analgesic, antispasmodic, and anticancer drug. Human serum albumin (HSA) is a principal extracellular protein with a high concentration in blood plasma and carrier for many drugs to different molecular targets. Since the carrying of drug by HSA may affect on its structure and action, we decided to investigate the interaction between HSA and isoimperatorin using fluorescence and UV spectroscopy. Fluorescence data indicated that isoimperatorin quenches the intrinsic fluorescence of the HSA via a static mechanism and hydrophobic interaction play the major role in the drug binding. The binding average distance between isoimperatorin and Trp 214 of HSA was estimated on the basis of the theory of Förster energy transfer. Decrease of protein surface hydrophobicity (PSH) was also documented upon isoimperatorin binding. Furthermore, the synchronous fluorescence spectra show that the microenvironment of the tryptophan residues does not have obvious changes. Site marker compettive and fluorescence experiments revealed that the binding of isoimperatorin to HSA occurred at or near site I. Finally, the binding details between isoimperatorin and HSA were further confirmed by molecular docking and esterase activity inhibition studies which revealed that drug was bound at subdomain IIA.