The whole antibodies used in immunoassays (a type of biocrhemical test that measures the presence or concentration of a macromolecule in a solution) such as ELISA, Immunohistochemistry, Flow Cytometry, or western blotting are vital for the detection of antigen, but sometimes a piece of antibody, or a specific part of the antibody molecular with discrete features is beneficial. This process involves antibody fragmentation. In some cases, antibody fragmentation such as Fab or F (ab’) 2 (a typical antibody pairs) is preferable to prevent the constant (Fc) portion from binding to cell surface receptors.
Antibody fragmentation is realized by selectively cleaving an antibody with proteases and/or by using reducing agents. In addition, recently scientists found that genetic engineering techniques can also express small fragments directly in new studies, but it’s still relatively new.
Usually standard antibody fragmentation methods are time and energy-consuming. Those processes require a large amount of labor investment such as the optimization of protease; control the pH of the reaction and type and amount of reducing agent etc.
Types of Antibody Fragments
There are some kinds of antibody fragments, such as Fab or F (ab’) 2 fragments (which can be gained by papain, pepsin or ficin digestion). The absence of Fc domain, leaving a bivalent Fab’2 fragment, for example in some conditions may be desirable to avoid unwanted binding moves. Or the requirement of small molecule, in tissue penetration for example,) Fab or F (ab’) 2 is usually preferred.
Advantages and Application of Antibody Fragments
Compared to whole antibody, antibody fragments have lower immunogenicity in vivo experiments. Due to this, they are commonly used as a starting point for drug molecules, in clinical toxicity experiments, in preparing pharmaceutical compositions for treating diseases or disorders.
With Fc interactions, their nonspecific binding is reduced.
Because of small size, they are more efficient in penetration of tissue for IHC. Because of the lack of glycosylation and relatively small size, they are easier and less costly to manufacture.
They are proved to better specific binding to Protein A in IP and WB experiments.
Generation of Antibody Fragmentation
As part of ongoing studies with regards to therapeutic antibodies sector, clinical sector, drug design sector and others, the fragmentation of antibodies are driven harder. They can maintain a high specificity and selectivity of antibodies—beneficial to researchers, while offering distinct biological profiles such as cheaper and faster manufacturing—great to suppliers, antibody fragments have no reason to be less popular. However, as mentioned above – antibodies fragmentation requires a large quantity of time, energy, expertise and it is technically challenging. To contribute to life science industry and help researchers, Creative Diagnostics provides custom antibody fragmentation services to meet a diverse set of customer needs.