Fab Antibody Labeling Service

Introduction of Fab Antibody Labeling ServiceFab

Among the marketed antibodies, the majority are fully human or humanized immunoglobulins (Igs), followed by a small fraction of antibody fragment-based therapeutics. Notably, full-length antibodies have a long circulating half-life, which makes them unsuitable for some diagnostic and therapeutic applications. With the conjugation of some anticancer products to the effector molecules (such as radiolabels, chemicals, or toxins), antibody–drug conjugates (ADCs) are expected to expand into fields other than malignant tumors and autoimmune diseases, and will dominate the field of drug discovery in the near future. However, the growing needs of the market require pure molecules in large amounts, which is challenging to the production cost, the productivity of expression systems, as well as the quality of expressed recombinant antibody fragments. The increasing market demand makes the production cost of antibody drugs, the yield and the quality of recombinant antibody fragments face great challenges. In recent years, with the continuous advancement of gene recombination and bioengineering technology, high-throughput screening and large-scale production of antibodies/antibody fragments have become a reality.

Fab antibody fragment is a region on an antibody that binds to an antigen. It contains a constant region and a variable region for each heavy and light chain. Fab antibody fragments (antigen-binding fragments on immunoglobulin (IgG)) have the following advantages: (1) Fab fragments have better tissue penetration and faster clearance ability than full-length monoclonal antibodies, and can better deliver radioisotopes, chemotherapy drugs or toxins to the target; (2) Fab fragment lacks Fc domain, which gives it the ability to univalent bind antigen without mediating antibody effect function, thus reducing immunogenicity; (3) Fab is more stable than scFv, can be expressed in E. coli, and its production is simple and low cost.

Figure 1: The structure of IgG and mAb-derived alternatives. IgG, immunoglobulin G; mAb, monoclonal antibody

Alpha Lifetech Can Provide

Alpha Lifetech is deeply committed to the frontiers of antibody engineering and technology application, and is dedicated to providing high-quality, customized biological solutions for global research and industrial customers. Our Fab antibody labeling service, with advanced molecular biology technology, strict quality control system and professional R&D team, has established an excellent reputation in the industry. Through precise Fab antibody expression and diversified antibody labeling technologies (including but not limited to antibody biotin labeling, antibody HRP (horseradish peroxidase) labeling and isotope labeling), we help our clients to unlock the deep mysteries of life sciences and accelerate the process of scientific research and drug development.

In the field of Fab antibody labeling services, we have significant advantages: we utilize highly efficient gene cloning and expression systems to ensure the accuracy and high purity of Fab fragments; we achieve stable binding of antibodies to biotin, HRP, and isotopes through delicate labeling processes, which significantly improves the sensitivity and specificity of the detection; at the same time, we strictly comply with the international quality management standards to ensure that every step of the operation meets the high requirements of scientific research and industrial applications. Meanwhile, we strictly follow the international quality control standards to ensure that every step of the operation meets the high requirements of scientific research and industrial applications.

Fab Antibody Labeling Service

Fab antibodies are coupled with functional molecules (including fluorophores, enzymes, isotopes, biotin, etc.) to perform additional functions of antibody fragments, such as as detection agents or ADCs. An ADC consists of a targeted portion represented by an mAb or antibody fragment and a cytotoxic compound chemically coupled or genetically fused. Because ADCs are better distributed or permeable in the body and immunogenicity is reduced, the therapeutic effect may increase.

Antibody Biotin LabelingLabeling

Biotin labeling reactions are often performed with biotin succinimide. Biotin is labeled by coupling reaction with free lysine of antibody molecule.

Antibody HRP LabelingLabeling

The sodium periodate method is commonly used to label antibodies with horseradish peroxidase (HRP). The principle is that the sugar group of HRP is oxidized with sodium periodate to aldehyde group, and the aldehyde group is combined with the amino group of IgG after adding antibody IgG to form Schiff's base. In order to prevent the coupling between the aldehyde group of the sugar in HRP and its own protein amino group, dinitrofluorobenzene was used to block the amino group before oxidation with sodium periodate. At the end of the oxidation reaction, Schiff's base is stabilized with sodium borohydride.

Isotope LabelingLabeling

Common methods of isotope labeling include iodine labeling and biosynthetic labeling. It is important to emphasize that knowledge of isotope manipulation and protection should be obtained before using isotopically labeled monoclonal antibodies or other proteins. Under normal circumstances should include avoiding physical contact and gamma; - Effective protection from radiation exposure, handling and use of isotopically labelled antibodies should use protective devices and reasonable disposal of radioactive waste.

Fab Antibody Labeling Service Workflow

Steps	QC Standard	Timeline	Delivery standards
Step1: Fab Antibody Expression	Purity >95%	2-3 weeks	Highly expressed Fab antibody
Step2: Antibody Purification-Purity Verification	No protein aggregates	1 week	High purity Fab antibody
Step3: Antibody Labeling	Choose the labeling method according to the customer's needs	1 week	Labeling Fab antibody
Step4: Purified Antibody After Modification	No unreacted biotin derivatives	1 week	Purified biotinylated Fab antibody
Step5: Biotinylation efficiency test	Confirmation of degree of biotinylation and homogeneity	1 week	Biotinylation efficiency report