Glycosylation is one of the common post-translational modifications of proteins to regulate the ability of tumor invasion, metastasis and tumor heterogeneity by interacting with glycan-binding proteins such as lectins and antibodies. Glycan microarray can be constructed by chemical synthesis, chemical-enzyme synthesis or natural glycan releasing. Glycan microarray is an essential analytical tool to discover the interaction between glycan and its binding proteins. Here we summarize the standard techniques to construct glycan microarray for the application in cancer vaccine, monoclonal antibody and diagnostic markers.
Antibodies, Monoclonal ; Glycosylation ; Lectins/metabolism* ; Microarray Analysis ; Neoplasms ; Polysaccharides

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 antibody-drug conjugate (ADC), a humanized or human monoclonal antibody conjugated with highly cytotoxic small molecules (payloads) through chemical linkers, is a novel therapeutic format and has great potential to make a paradigm shift in cancer chemotherapy. This new antibody-based molecular platform enables selective delivery of a potent cytotoxic payload to target cancer cells, resulting in improved efficacy, reduced systemic toxicity, and preferable pharmacokinetics (PK)/pharmacodynamics (PD) and biodistribution compared to traditional chemotherapy. Boosted by the successes of FDA-approved Adcetris and Kadcyla, this drug class has been rapidly growing along with about 60 ADCs currently in clinical trials. In this article, we briefly review molecular aspects of each component (the antibody, payload, and linker) of ADCs, and then mainly discuss traditional and new technologies of the conjugation and linker chemistries for successful construction of clinically effective ADCs. Current efforts in the conjugation and linker chemistries will provide greater insights into molecular design and strategies for clinically effective ADCs from medicinal chemistry and pharmacology standpoints. The development of site-specific conjugation methodologies for constructing homogeneous ADCs is an especially promising path to improving ADC design, which will open the way for novel cancer therapeutics.
Amino Acids ; metabolism ; Animals ; Antibodies, Monoclonal ; chemistry ; metabolism ; Antigens ; metabolism ; Genetic Engineering ; Humans ; Immunoconjugates ; chemistry ; metabolism

As of May 1, 2017, 74 antibody-based molecules have been approved by a regulatory authority in a major market. Additionally, there are 70 and 575 antibody-based molecules in phase III and phase I/II clinical trials, respectively. These total 719 antibody-based clinical stage molecules include 493 naked IgGs, 87 antibody-drug conjugates, 61 bispecific antibodies, 37 total Fc fusion proteins, 17 radioimmunoglobulins, 13 antibody fragments, and 11 immunocytokines. New uses for these antibodies are being discovered each year. For oncology, many of the exciting new approaches involve antibody modulation of T-cells. There are over 80 antibodies in clinical trials targeting T cell checkpoints, 26 T-cell-redirected bispecific antibodies, and 145 chimeric antigen receptor (CAR) cell-based candidates (all currently in phase I or II clinical trials), totaling more than 250 T cell interacting clinical stage antibody-based candidates. Finally, significant progress has been made recently on routes of delivery, including delivery of proteins across the blood-brain barrier, oral delivery to the gut, delivery to the cellular cytosol, and gene- and viral-based delivery of antibodies. Thus, there are currently at least 864 antibody-based clinical stage molecules or cells, with incredible diversity in how they are constructed and what activities they impart. These are followed by a next wave of novel molecules, approaches, and new methods and routes of delivery, demonstrating that the field of antibody-based biologics is very innovative and diverse in its approaches to fulfill their promise to treat unmet medical needs.
Animals ; Antibodies, Bispecific ; metabolism ; Antibodies, Monoclonal ; metabolism ; Drug Delivery Systems ; Humans ; Immunoconjugates ; metabolism ; Protein Engineering ; methods ; trends ; T-Lymphocytes ; metabolism

AIMTo detect the expression of a novel protein, hemangiopoietin (HAPO), in the human fetal liver at the protein level.

METHODSMonoclonal antibodies (moAbs) against HAPO were produced by traditional hybridoma technique. Their affinities were calculated from the results of non-competitive ELISA and the antibodies were purified by protein G affinity chromatography. Expression of HAPO in the liver was detected by SDS-PAGE and Western blot.

RESULTSFive strains of moAbs were screened out in total, among which three were IgG1 and the other two were IgM. Their light trains were all belonged to kappa. The relative affinities of the three IgG1 form moAbs were 3.06 x 10(9) mol/L, 6.07 x 10(8) mol/L and 1.71 x 10(10) mol/L respectively. After purification, the purity of the moAbs could reach more than 99%. HAPO expression was detected at the protein level in the human fetal liver, and the apparent molecular weight of the nature HAPO was very close to but a little higher than our recombinant one.

CONCLUSIONHAPO was expressed in the human fetal liver at the protein level.

Antibodies, Monoclonal ; Blotting, Western ; Fetus ; Humans ; Immunoblotting ; Liver ; embryology ; metabolism ; Proteoglycans ; metabolism

Coronavirus disease (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), with strong contagiousness, high susceptibility and long incubation period. cell entry by SARS-CoV-2 requires the binding between the receptor-binding domain of the viral spike protein and the cellular angiotensin-converting enzyme 2 (ACE2). Here, we briefly reviewed the mechanisms underlying the interaction between SARS-CoV-2 and ACE2, and summarized the latest research progress on SARS-CoV-2 neutralizing monoclonal antibodies and nanobodies, so as to better understand the development process and drug research direction of COVID-19. This review may facilitate understanding the development of neutralizing antibody drugs for emerging infectious diseases, especially for COVID-19.
Angiotensin-Converting Enzyme 2 ; Antibodies, Monoclonal ; Antibodies, Neutralizing ; Antibodies, Viral ; COVID-19 ; Humans ; Peptidyl-Dipeptidase A/metabolism* ; Protein Binding ; SARS-CoV-2 ; Single-Domain Antibodies ; Spike Glycoprotein, Coronavirus/metabolism*

OBJECTIVETo study the mechanism of cardiotoxicity associated with Herceptin.

METHODSHerceptin was labeled with iodine-131 using the Iodogen method. Radioimmunoimaging was performed in 5 rabbits at 3 h to 5 days following (131)I-Herceptin injection to investigate the biodistribution of Herceptin. (131)I-Herceptin uptake in each organ or tissue relative to that in the muscular tissue (O/M ratio) was calculated and compared. On the fifth day following the injection, the organs including the heart, lung, liver and muscles were taken for measurement of the weight and radiocounts. HER2 expression was measured by immunohistochemistry in these organs and tissues.

RESULTSThe O/M ratio of the heart was significantly higher than that of the lung (P=0.032) and liver (P=0.019) at 3 h after Herceptin injection, but reduced significantly at 24 h (P=0.001). The uptake of (131)I-Herceptin in the myocardium was slightly higher that that in the muscle and intestine, but lower than that in the lung and spleen. HER2 expression showed no significant difference between the myocardium and the other tissues such as the liver, lung, and kidney (H=3.236, P=0.172).

CONCLUSIONMyocardium expresses low levels of HER2 and accumulates Herceptin no more than the other tissues.

Animals ; Antibodies, Monoclonal ; administration & dosage ; pharmacokinetics ; toxicity ; Antibodies, Monoclonal, Humanized ; Female ; Iodine Radioisotopes ; administration & dosage ; pharmacokinetics ; Male ; Myocardium ; metabolism ; Rabbits ; Radioimmunodetection ; Receptor, ErbB-2 ; metabolism ; Tissue Distribution ; Trastuzumab

Therapeutic monoclonal antibodies are among the most effective biotherapeutics to date. An important aspect of antibodies is their ability to bind antigen while at the same time recruit immune effector functions. The majority of approved recombinant monoclonal antibody therapies are of the human IgG1 subclass, which can engage both humoral and cellular components of the immune system. The wealth of information generated about antibodies has afforded investigators the ability to molecularly engineer antibodies to modulate effector functions. Here, we review various antibody engineering efforts intended to improve efficacy and safety relative to the human IgG isotype. Further, we will discuss proposed mechanisms by which engineering approaches led to modified interactions with immune components and provide examples of clinical studies using next generation antibodies.
Animals ; Antibodies, Monoclonal ; metabolism ; Antigens ; metabolism ; Complement System Proteins ; metabolism ; Humans ; Immunoglobulin G ; metabolism ; Protein Engineering ; Receptors, Fc ; metabolism

OBJECTIVESTo investigate the intralaboratory reproducibility of immunohistochemistry (IHC) testing for HER2 status in breast cancer, and to evaluate the factors which influence the reproducibility. The concordance between monoclonal antibody CB11 and HercepTest was also assessed.

METHODSHER2 overexpression on paraffin sections from thirty-seven cases of breast invasive ductal carcinoma was evaluated using CB11 and the evaluation procedure had been repeated for five times scored the tests together according to the HercepTest and new American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) grading schemes by 2 experienced pathologists together. Reproducibility rates of the five rounds were assessed using Kappa statistic, and the results from two scoring systems were compared. HercepTest kit was applied to the same cases afterward and the results were compared with CB11.

RESULTSSubstantial intralaboratory reproducibility was achieved among 5 rounds tests. Excluding the influence effect of changing antibody lots, the intralaboratory reproducibility was closed to the perfect threshold (Kappa = 0.7858, HercepTest scheme). The results derived from the two grading schemes had an almost perfect agreement (Kappa = 0.8549). The concordance (positive vs. negative) between CB11 and HercepTest was 83.78%.

CONCLUSIONSLaboratory work with strict supervision and more experience will ensure a reliable testing consistency. Reproducibility analysis could be adopted to evaluate the intralaboratory staining quality on HER2 testing. Different antibody lots bring some influence to the intralaboratory reproducibility, but not significant. CB11 could be accepted to screen HER2 status in routine practice after testing validation.

Antibodies, Monoclonal ; metabolism ; Breast Neoplasms ; metabolism ; Carcinoma, Ductal, Breast ; metabolism ; Female ; Humans ; Immunohistochemistry ; methods ; Receptor, ErbB-2 ; metabolism ; Reproducibility of Results

OBJECTIVETo develop a monoclonal antibody (mAb) directed to FVIII C2 domain and investigate its effect on FVIII activity.

METHODSFVIII C2 protein was expressed in E. coli and purified. A murine antihuman FVIII C2 domain mAb SZ-132 was developed by standard hybridoma technology and characterized. In coagulation assays, different concentrations of SZ-132 were incubated with freshly collected pooled human plasma and the residual activity of FVIII and activated partial thromboplastin time (APTT) were determined. The effects of SZ-132 on rhFVIII binding to purified human vWF, phosphatidylserine (PS) and platelets were assessed by enzyme linked immunosorbent assays (ELISA).

RESULTSSZ-132 could inhibit FVIII procoagulant activity in a dose-dependent manner within the concentrations of 0-25 microg/ml and the FVIII activity was completely inhibited on above 25 microg/ml. It could also prevent rhFVIII from binding to vWF, PS and platelets.

CONCLUSIONSSZ-132 is a neutralizing mAb against FVIII C2 domain and can inhibit FVIII procoagulant activity by preventing FVIII from binding to vWF and PS.

Animals ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Antibodies, Neutralizing ; biosynthesis ; immunology ; Factor VIII ; immunology ; metabolism ; Humans ; Male ; Mice ; Mice, Inbred BALB C