Monoclonal antibody (mAb) is an important biological macromolecule and widely used in immune detection, in vitro diagnostics, and drug discovery. However, the inherent properties of mAb restrict its further development, such as high molecular weight and complex structure. Therefore, there is an urgent need to develop alternatives for mAb. Various types of miniaturized antibodies have been developed, among which the variable domain of immunoglobulin new antigen receptor (VNAR) is very attractive. The shark single-domain antibody, also known as shark VNAR, is an antigen-binding domain obtained by genetic engineering technology based on the immunoglobulin new antigen receptor (IgNAR) that naturally exists in selachimorpha. It has a molecular weight of 12 kDa, which is the smallest antigen-binding domain found in the known vertebrates at present. Compared with mAb, the shark VNAR exhibits various superiorities, such as low molecular weight, high affinity, tolerance to the harsh environment, good water solubility, strong tissue penetration, and recognition of the hidden epitopes. It has attracted wide attention in the fields of immunochemical reagents and drug discovery. In this review, various aspects of shark VNAR are elaborated, including the structural and functional characteristics, generating and humanization techniques, affinity maturation strategies, application fields, advantages and disadvantages, and prospects.
Animals ; Antibodies, Monoclonal ; immunology ; Antibodies, Monoclonal, Humanized ; immunology ; Antigens ; Epitopes ; metabolism ; Protein Domains ; immunology ; Receptors, Antigen ; chemistry ; immunology ; Sharks

The voltage-gated Na channel subtype Nav1.7 is important for pain and itch in rodents and humans. We previously showed that a Nav1.7-targeting monoclonal antibody (SVmab) reduces Na currents and pain and itch responses in mice. Here, we investigated whether recombinant SVmab (rSVmab) binds to and blocks Nav1.7 similar to SVmab. ELISA tests revealed that SVmab was capable of binding to Nav1.7-expressing HEK293 cells, mouse DRG neurons, human nerve tissue, and the voltage-sensor domain II of Nav1.7. In contrast, rSVmab showed no or weak binding to Nav1.7 in these tests. Patch-clamp recordings showed that SVmab, but not rSVmab, markedly inhibited Na currents in Nav1.7-expressing HEK293 cells. Notably, electrical field stimulation increased the blocking activity of SVmab and rSVmab in Nav1.7-expressing HEK293 cells. SVmab was more effective than rSVmab in inhibiting paclitaxel-induced mechanical allodynia. SVmab also bound to human DRG neurons and inhibited their Na currents. Finally, potential reasons for the differential efficacy of SVmab and rSVmab and future directions are discussed.
Animals ; Antibodies, Monoclonal ; therapeutic use ; Biotin ; metabolism ; Cells, Cultured ; Disease Models, Animal ; Female ; Ganglia, Spinal ; cytology ; HEK293 Cells ; Humans ; Hybridomas ; chemistry ; Hyperalgesia ; drug therapy ; Male ; Mice ; Mice, Inbred C57BL ; NAV1.5 Voltage-Gated Sodium Channel ; metabolism ; NAV1.7 Voltage-Gated Sodium Channel ; chemistry ; immunology ; metabolism ; Neuralgia ; drug therapy ; metabolism ; Protein Binding ; drug effects ; Recombinant Proteins ; biosynthesis ; therapeutic use ; Sensory Receptor Cells ; drug effects ; physiology

Entero virus 71 (EV71) causes hand, foot, and mouth disease (HFMD) and occasionally leads to severe neurological complications and even death. Scavenger receptor class B member 2 (SCARB2) is a functional receptor for EV71, that mediates viral attachment, internalization, and uncoating. However, the exact binding site of EV71 on SCARB2 is unknown. In this study, we generated a monoclonal antibody (mAb) that binds to human but not mouse SCARB2. It is named JL2, and it can effectively inhibit EV71 infection of target cells. Using a set of chimeras of human and mouse SCARB2, we identified that the region containing residues 77-113 of human SCARB2 contributes significantly to JL2 binding. The structure of the SCARB2-JL2 complex revealed that JL2 binds to the apical region of SCARB2 involving α-helices 2, 5, and 14. Our results provide new insights into the potential binding sites for EV71 on SCARB2 and the molecular mechanism of EV71 entry.
Amino Acid Sequence ; Animals ; Antibodies, Monoclonal ; chemistry ; genetics ; metabolism ; Binding Sites ; Cell Line ; Crystallography, X-Ray ; Enterovirus A, Human ; drug effects ; genetics ; growth & development ; immunology ; Fibroblasts ; drug effects ; virology ; Gene Expression ; HEK293 Cells ; Humans ; Immunoglobulin Fab Fragments ; chemistry ; genetics ; metabolism ; Lysosome-Associated Membrane Glycoproteins ; chemistry ; genetics ; immunology ; Mice ; Models, Molecular ; Protein Binding ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; Protein Interaction Domains and Motifs ; Receptors, Scavenger ; chemistry ; genetics ; immunology ; Receptors, Virus ; chemistry ; genetics ; immunology ; Recombinant Fusion Proteins ; chemistry ; genetics ; immunology ; Sequence Alignment ; Sequence Homology, Amino Acid ; Sf9 Cells ; Spodoptera ; Thermodynamics

OBJECTIVETo detect platelet anti-HPA-1a and -1b antibodies using recombinant GPIIIa fragments coupled to Luminex beads.

METHODSThe sensitivity of 2 techniques, monoclonal antibody specific immobilization of platelet antigen (MAIPA) and Luminex bead assay, was compared using 12 twofold-serial dilutions (from neat to 1 in 2048) of an anti-HPA-1a WHO international standard. The specificity of Luminex assay to identify anti-HPA-1a and -1b antibodies was assessed using 8 negative or positive controls and 36 blinded samples provided by WHO Platelet Workshop.

RESULTSThe sensitivity of MAIPA and Luminex bead assay to detect anti-HPA-1a was dilution 1/64 (i.e. 1.56 IU/ml) and far more than dilution 1/2048 (i.e. 0.049 IU/mL), respectively. The Luminex bead assay could specifically identify negative and positive controls of anti-HPA-1a and -1b. All results of 36 blinded samples by Luminex assay were accordant to reference results except one sample which contained high concentration antithetical antibody and resulted in false positive of anti-HPA-1b. Cross-reactivity was also not observed with the samples containing HLA, ABO or other platelet antibodies.

CONCLUSIONThe Luminex beads coupled with recombinant GPIIIa fragments can be used to detect HPA-1 system antibodies with sufficient sensitivity and specificity, that is suitable for the detection of platelet alloantibodies in clinical alloimmune thrombocytopenia.

Antibodies, Monoclonal ; Antigens, Human Platelet ; immunology ; Blood Platelets ; Humans ; Integrin beta3 ; chemistry ; Isoantibodies ; blood ; Purpura, Thrombocytopenic, Idiopathic ; diagnosis ; Recombinant Proteins ; chemistry ; Sensitivity and Specificity

With the application of monoclonal antibody technology more and more widely, its production technology is becoming more and more perfect. Small molecule monoclonal antibody technology is becoming a hot research topic for people. The application of traditional Chinese medicine small molecule monoclonal antibody technology has been more and more widely, the technology for effective Chinese medicine component knockout provide strong technical support. The preparation of monoclonal antibodies and small molecule knockout technology are reviewed in this paper. The preparation of several steps, such as: in the process of preparation of antigen, hapten carrier coupling, coupling ratio determination and identification of artificial antigen and establishment of animal immunization and hybridoma cell lines of monoclonal antibody, the large-scale preparation; small molecule monoclonal antibody on Immune in affinity chromatography column method is discussed in detail. The author believes that this technology will make the traditional Chinese medicine research on a higher level, and improve the level of internationalization of Chinese medicine research.
Animals ; Antibodies, Monoclonal ; chemistry ; genetics ; immunology ; Humans ; Hybridomas ; metabolism ; Immunologic Techniques ; methods ; trends

OBJECTIVE: To synthesize mesoporous silica-core-shell magnetic nanoparticles (MNPs) encapsulated by liposomes (Lipo [MNP@m-SiO2]) in order to enhance their stability, allow them to be used in any buffer solution, and to produce trastuzumab-conjugated (Lipo[MNP@m-SiO2]-Her2Ab) nanoparticles to be utilized in vitro for the targeting of breast cancer. MATERIALS AND METHODS: The physiochemical characteristics of Lipo[MNP@m-SiO2] were assessed in terms of size, morphological features, and in vitro safety. The multimodal imaging properties of the organic dye incorporated into Lipo[MNP@m-SiO2] were assessed with both in vitro fluorescence and MR imaging. The specific targeting ability of trastuzumab (Her2/neu antibody, Herceptin(R))-conjugated Lipo[MNP@m-SiO2] for Her2/neu-positive breast cancer cells was also evaluated with fluorescence and MR imaging. RESULTS: We obtained uniformly-sized and evenly distributed Lipo[MNP@m-SiO2] that demonstrated biological stability, while not disrupting cell viability. Her2/neu-positive breast cancer cell targeting by trastuzumab-conjugated Lipo[MNP@m-SiO2] was observed by in vitro fluorescence and MR imaging. CONCLUSION: Trastuzumab-conjugated Lipo[MNP@m-SiO2] is a potential treatment tool for targeted drug delivery in Her2/neu-positive breast cancer.
3T3 Cells ; Animals ; Antibodies, Monoclonal, Humanized/*administration & dosage ; Antineoplastic Agents/*administration & dosage ; Breast Neoplasms/chemistry/*drug therapy ; Cell Line, Tumor ; Drug Delivery Systems/methods ; Female ; Ferric Compounds/chemistry ; Humans ; Liposomes ; Magnetite Nanoparticles/administration & dosage/*chemistry ; Mice ; Molecular Targeted Therapy/methods ; Nanoconjugates/administration & dosage/*chemistry ; Nanoparticles/chemistry ; *Receptor, erbB-2/immunology ; Silicon Dioxide/administration & dosage/*chemical synthesis/chemistry

OBJECTIVETo identify the self-preparation monoclonal antibody which target to clenbuterol, and set up the standard curve to clenbuterol (CL) detection.

METHODSThe affinity constants and activity of the monoclonal antibody which target to CL were determined by ELISA. ELISA was also used to confirm whether the monoclonal antibody had any across-reaction with BSA and CL analogues. The rat ascites which contains the monoclonal antibody target to CL was purified by (NH4)2SO4 salt-out method and further by affinity column. At last, the CL detection standard curve which based on indirect competition ELISA was established.

RESULTSThe ELISA experiment showed that the antibody titer was 10(6) and the monoclonal antibody affinity constants was 2.90 x 10(10) L/mol. The result of the indirect competition ELISA confirmed that the monoclonal antibody had no cross-reaction with BSA and a few kind of CL analogue. CL detection standard curve based on indirect competition ELISA was established, which R2 was 0.9812, and the lowest detectable limit was 1.0 ng/ml.

CONCLUSIONThe standard curve based on indirectly competitioning ELISA was established. The self-preparation monoclonal antibody which target to CL has high affinity and high specific to CL, which had established the foundation to the advanced development of the CL immune test paper and CL ELISA kit.

Animals ; Antibodies, Monoclonal ; chemistry ; isolation & purification ; Antibody Affinity ; Clenbuterol ; immunology ; Cross Reactions ; Enzyme-Linked Immunosorbent Assay ; Limit of Detection ; Rats

Antibodies, Monoclonal ; chemistry ; immunology ; Antigens, Viral ; chemistry ; genetics ; immunology ; Binding Sites ; Capsid Proteins ; chemistry ; genetics ; immunology ; Epitopes ; chemistry ; genetics ; immunology ; Escherichia coli ; genetics ; metabolism ; Gene Expression ; Hepatitis E ; immunology ; prevention & control ; virology ; Hepatitis E virus ; chemistry ; immunology ; Humans ; Molecular Docking Simulation ; Mutagenesis, Site-Directed ; Peptide Mapping ; Protein Binding ; Recombinant Proteins ; chemistry ; genetics ; immunology ; Viral Hepatitis Vaccines ; administration & dosage ; biosynthesis

OBJECTIVETo prepare a new targeted liposome ultrasonic contrast agent with anti-KDR antibody that binds specifically with KDR as the main receptor of VEGF and evaluate its physical characteristics, biological activity and specific binding capability in vitro.

METHODSA sonicator was used to prepare the biotinylated lipid micro-bubbles (MB-B), and biotin-avidin-mediated technique was used for attachment of anti-mouse KDR monoclonal antibody to the micro-bubble shell to generate MB-BAB-KDR. MB-BAB-KDR was incubated with fluorescent second antibody to assess the link condition, and the control groups were the MB-B and micro-bubbles with the antibody alone (MB-B-KDR). A parallel plate flow chamber system was used to characterize micro-bubbles attachment efficiency to KDR Fc.

RESULTSThe surface of the micro-bubbles could carry KDR antibody through the biotin-avidin bridge and MB-BAB-KDR were spherical and well-distributed. After incubation with the second antibody, MB-BAB-KDR could be observed to emit bright green fluorescence (Grade II) as compared with little or weak fluorescence in the control MB-B group (Grade 0) and MB-B-KDR group (Grade I). Targeted micro-bubbles bound to KDR Fc increased as the KDR Fc concentration increased (P<0.05).

CONCLUSIONThe targeted liposome contrast agent linked with KDR antibody by biotin-avidin bridge we prepared shows an increased binding number as the KDR Fc concentration increases, which provides a novel approach to molecular imaging study of endometrial receptivity.

Animals ; Antibodies, Monoclonal ; Contrast Media ; chemistry ; Endometrium ; physiology ; Female ; Liposomes ; chemistry ; Mice ; Microbubbles ; Molecular Imaging ; Sonication ; Ultrasonography ; Vascular Endothelial Growth Factor Receptor-2 ; immunology

A sensitive antibody-based lateral flow dipstick was developed for ginsenoside Re (GRe) detection. The stick consisted of a sample pad, a conjugate pad, membrane and an absorbent pad. The membrane was coated with two capture reagents, GRe-BSA conjugate and goat anti-mouse antibodies, forming a test line and a control line, respectively. The conjugate pad was saturated with colloidal gold particles coated with affinity purified monoclonal anti-GRe antibody. The visual detection limit was 200 microg x L(-1) of GRe and the reaction time was 10 min. The Panax ginseng roots were identified after these samples (10 mg) were extracted with 5 mL tap water for 30 min at room temperature, and the extracts were tested by the dipsticks and ELISA kit. The true and false P. ginseng could be distinguished with dipsticks. The dipstick could be used to detect the quality of the P. ginseng samples when the extract was diluted 100-folds. The results were compared with those obtained using an indirect competitive enzyme-linked immunosorbent assay (icELISA). The dipstick assay proved to be a sensitive and rapid tool for quality control of P. ginseng.
Animals ; Antibodies, Monoclonal ; immunology ; Counterfeit Drugs ; analysis ; Ginsenosides ; analysis ; Immunoassay ; instrumentation ; methods ; Mice ; Panax ; chemistry ; Reagent Strips ; Time Factors