Antibody-drug conjugates utilize the antibody as a delivery vehicle for highly potent cytotoxic molecules with specificity for tumor-associated antigens for cancer therapy. Critical parameters that govern successful antibody-drug conjugate development for clinical use include the selection of the tumor target antigen, the antibody against the target, the cytotoxic molecule, the linker bridging the cytotoxic molecule and the antibody, and the conjugation chemistry used for the attachment of the cytotoxic molecule to the antibody. Advancements in these core antibody-drug conjugate technology are reflected by recent approval of Adectris(R) (anti-CD30-drug conjugate) and Kadcyla(R) (anti-HER2 drug conjugate). The potential approval of an anti-CD22 conjugate and promising new clinical data for anti-CD19 and anti-CD33 conjugates are additional advancements. Enrichment of antibody-drug conjugates with newly developed potent cytotoxic molecules and linkers are also in the pipeline for various tumor targets. However, the complexity of antibody-drug conjugate components, conjugation methods, and off-target toxicities still pose challenges for the strategic design of antibody-drug conjugates to achieve their fullest therapeutic potential. This review will discuss the emergence of clinical antibody-drug conjugates, current trends in optimization strategies, and recent study results for antibody-drug conjugates that have incorporated the latest optimization strategies. Future challenges and perspectives toward making antibody-drug conjugates more amendable for broader disease indications are also discussed.
Antibodies ; Chemistry ; Immunotherapy ; Sensitivity and Specificity

Antibody drug conjugates (ADCs) are an emerging class of targeted therapeutics with the potential to improve therapeutic index over the traditional chemotherapy. However, it is difficult to control the site and stoichiometry of conjugation in mAb, typically resulting in heterogeneous mixtures of ADCs that are difficult to optimize. New methods for site-specific drug attachment allow development of more homogeneous conjugates and control of the site of drug attachment. In this article, the new literature on development of ADCs and site-specific ADCs is reviewed. In addition, we summarized the various strategies in production of site-specific ADCs.
Antibodies, Monoclonal ; chemistry ; Antibody Specificity ; Binding Sites, Antibody ; Immunoconjugates ; chemistry

In order to enhance the specificity of TNF-α monoclonal antibody to inflamed site, a bispecific antibody BsDb that targets TNF-α and the extra-domain B (ED-B) of fibronectin (FN) was constructed by covalently linking the anti-TNF-α single chain Fv antibody (TNF-scFv) and the anti-ED-B scFv L19 via a flexible peptide linker deriving from human serum albumin (HSA). ED-B is an antigen specifically expressed at the inflamed site. BsDb is expressed in E. coli, identified by immunoblot, and purified with affinity chromatography. This was followed by further examination of its bioactivities and pharmacokinetics. We demonstrated that BsDb retained the immunoreactivity of its original antibodies as it could simultaneously bind to TNF-α and ED-B and neutralize the biological action of TNF-α. In the collagen-induced arthritis mice model, BsDb selectively accumulate in the inflamed joint with a maximal uptake of (12.2 ± 1.50)% ID/g in a single inflamed paw and retain in the inflamed paw for at least 72 h. In contrast, BsDb showed a short serum half-life of (0.50 ± 0.05) h and a rapid clearance from normal tissues. The findings reported herein indicate that BsDb has good specificity to the inflamed site and low toxicity to normal tissues. BsDb is therefore likely to have greater clinical applications in the treatment of rheumatoid arthritis and other autoimmune diseases. This laid a stable basis for its preclinical study.
Animals ; Antibodies, Bispecific ; chemistry ; Antibodies, Monoclonal ; chemistry ; Arthritis, Experimental ; Escherichia coli ; Fibronectins ; chemistry ; Half-Life ; Humans ; Mice ; Single-Chain Antibodies ; chemistry ; Tumor Necrosis Factor-alpha ; chemistry

This study aimed at immobilizing the antibodies on the surfaces of the solid host membranes in order to improve the property of the biomaterial. The von Willebrand factor (vWf) antibodies were immobilized on the surface of Bombyx mori silk fibroin and PLA (Poly Lactic Acid) membrane by NH3 plasma treatment followed by covalent cross-linking reaction. The immobilization efficiency was evaluated by two methods including the antibody surplus and enzyme-linked immunosorbent assay (ELISA). The in vitro antithrombogenicity representing the activity of immobilized vWf antibody was determined by the method of Activated Partial Thromboplastin Time (APTT), Prothrombin Time (PT) and Thrombin Time (TT) test. The results demonstrate that the vWf antibodies are immobilized on silk fibroin and PLA membranes in an efficient way with the efficiency of antibody surplus up to 23.88% and ELISA reaction is positive. APTT and TT exceeded the upper limits distinctly, but the value of PT did not change noticeably. The in vitro antithrombogenicity represented the is activity-retaining form of antibodies. These results extend the application of antibody immobilization technique and provide a new idea about the design of biomaterials relating to the coagulation factors.
Antibodies ; chemistry ; Lactic Acid ; chemistry ; Polyesters ; Polymers ; chemistry ; von Willebrand Factor ; immunology

In order to optimize the fabrication of SiO2 tubes immobilized with antibody for hepatitis C virus antigen (HCAg) detection, we formed the activated amino on the surface of SiO2 tubes by using the activation of aminosilane. Then we immobilized the hepatitis C virus (HCV) monoclonal antibody on the surface of SiO2 tubes by using glutaraldehyde as a chemical cross-linker, followed by detecting HCAg. Sequence tests showed that when the SiO2 tubes were treated in 10% (V/V) aminosilane solution and 3% (V/V) glutaraldehyde solution for 3 hours and 2 hours, respectively, the HCV monoclonal antibody had high immobilization efficiency and low nonspecificity, and the HCAg was detected to 1 ng/mL. This experiment can provide principle and experimental data for establishment of HCAg magnetic immunoassay system.
Antibodies, Immobilized ; immunology ; Antibodies, Monoclonal ; chemistry ; immunology ; Hepatitis C Antibodies ; chemistry ; immunology ; Hepatitis C Antigens ; analysis ; immunology ; Humans ; Silicon Dioxide ; chemistry

Paf1 complex was identified in yeast and characterized to function in transcription and its related events. We identified the Drosophila homological components of paf1, CDC73 and RTF1 of paf1 complex. The genes encoding Drosophila paf1, CDC73 and RTF1 were cloned and expressed. With the purified recombinant proteins of truncated components of paf1 complex, antibodies against the Drosophila paf1, CDC73 and RTF1 were generated. These antibodies have been shown to be able to detect the endogenous paf1 subunits as well as their human counterparts in the HeLa extract. On Drosophila polytene chromosomes, these antibodies have been demonstrated to locate the paf1 complex at actively transcribing sites, which co-localized with phosphorylated RNA polymerase II, indicating that paf1 complex in Drosophila is involved in transcription or the events coupling with transcription.
Animals ; Antibodies ; chemistry ; Drosophila Proteins ; immunology ; Drosophila melanogaster

Antibody, the major effector in adaptive immunity, plays key roles in protective and pathogenic immune responses. Integrative analyses of antibody development, differentiation, and maturation promote the research in immune mechanism, vaccine design, and therapies for autoimmune disorders. The development of next generation sequencing technologies has enabled large-scale characterization of functional antibody repertoires. With the advantages of next generation sequencing, antibody and antibody repertoire analysis have been successfully used in identification of HIV-1-broadly neutralizing antibodies, design of rationale structure-based vaccine, and development of immunology. With increasing sequence length and precision, improvement of experimental protocols and bioinformatics analyses, and development of single cell sequencing technology, antibody repertoire sequencing will expedite the research in antibody-related immune response, and thus facilitates vaccine design for infectious diseases, clinical diagnosis and interference of autoimmune diseases. This review introduces the technologies, progresses, applications, and caveats of antibody repertoire sequencing.
Antibodies ; chemistry ; Antibodies, Neutralizing ; Antibody Formation ; HIV-1 ; High-Throughput Nucleotide Sequencing ; Humans ; Vaccines

The polyclonal antibodies against VLDL receptor were prepared and identified. Rabbits were immunized with polypeptide fragment of VLDL receptor as antigen. The collected blood serum of the immunized rabbits was analyzed and identified by using ELISA and Western Blot. The results showed that the rabbit against mouse and human VLDL receptor antibodies were obtained with high titer and could recognize the natural VLDL receptors through Western blot. The prepared polyclonal antibodies against VLDL receptor provide a new tool to study the protein of VLDL receptor.
Antibodies/chemistry ; Antibodies/*immunology ; Enzyme-Linked Immunosorbent Assay ; Peptides/*immunology ; Receptors, LDL/*immunology

The purpose of the study is to explore the in vitro refolding protocol for humanized anti-CTLA4-scFv expressed in E. coli. The inclusion bodies are denatured and then diluted or dialyzed into a refolding buffer. We analyzed several factors affecting the refolding yield, including refolding time, temperature, and redox environment. The refolded target proteins are analyzed by non-reducing SDS-PAGE, and the concentration of refolded proteins are examined by Bio-Rad Dc Protein Assay kit. The result shows that a high yield of the protein with natural conformation can be acquired in the condition of 0.15 mol x L(-1) sodium chloride, 50 mmol x L(-1) Tirs-HCl, pH 8.0 buffer containing 1 micromol x L(-1) reduced glutathione and 3 micromol x L(-1) oxidized glutathione. The refolding time is 48 to 54 h at 4 degrees C. 28 mg refolded proteins are produced from 3.9g E. coli.
Antibodies, Monoclonal, Humanized ; chemistry ; CTLA-4 Antigen ; chemistry ; Escherichia coli ; metabolism ; Humans ; Inclusion Bodies ; chemistry ; Protein Folding ; Single-Chain Antibodies ; chemistry

A human immunodeficiency virus type-1 (HIV-1) vaccine which is able to effectively prevent infection would be the most powerful method of extinguishing pandemic of the acquired immunodeficiency syndrome (AIDS). Yet, achieving such vaccine remains great challenges. The membrane-proximal external region (MPER) is a highly conserved region of the envelope glycoprotein (Env) gp41 subunit near the viral envelope surface, and it plays a key role in membrane fusion. It is also the target of some reported broadly neutralizing antibodies (bNAbs). Thus, MPER is deemed to be one of the most attractive vaccine targets. However, no one can induce these bNAbs by immunization with immunogens containing the MPER sequence(s). The few attempts at developing a vaccine have only resulted in the induction of neutralizing antibodies with quite low potency and limited breadth. Thus far, vaccine failure can be attributed to various characteristics of MPER, such as those involving structure and immunology; therefore, we will focus on these and review the recent progress in the field from the following perspectives: (1) MPER structure and its role in membrane fusion, (2) the epitopes and neutralization mechanisms of MPER-specific bNAbs, as well as the limitations in eliciting neutralizing antibodies, and (3) different strategies for MPER vaccine design and current harvests.
AIDS Vaccines ; chemistry ; immunology ; Antibodies, Neutralizing ; immunology ; HIV Antibodies ; immunology ; HIV Envelope Protein gp41 ; immunology ; HIV-1 ; chemistry ; immunology ; Humans