Fab is the abbreviation of Fragment of antigen binding, which is a region of an antibody that can bind to an antigen.

The fragment is composed of a complete light chain and the VH and CH1 domain (Fd section ) of the heavy chain. It has a molecular weight of about 5 x 104. To know about monoclonal antibody production service online you can search the browser.

Both the light chain and the large chain have a constant region and a changeable area, and there are disulfide connections between the heavy and light chains.

Currently, Fab antibody (Fa) fragments can be ready in the laboratory. Papain separates the IgG (immunoglobulin G) in the near-N-terminus of this inter-heavy cable disulfide linkage in the hinge region, forming two identical monovalent antigen-binding parts and a crystallizable part.

The monovalent antigen-binding parts are abbreviated as the FAB section, the crystallizable fragment is abbreviated as Fc scrap (Fragment crystallized).

A fragment is monovalent and can bind to antigen with no agglutination of precipitation. The Fc part has no antigen-binding action and is the site where IgG associates with effector cells or molecules.

The preparation of Fab fragment

Now, there are methods of enzymatic hydrolysis, preparation using expression systems, and antibody library deletion using phage display technology to prepare it.

Enzymatic hydrolysis generally takes advantage of papain or pepsin to demote human immunoglobulin G to get products like F(ab')2, Fab, and Fc fragments; The prep using expression systems, which normally benefit from E. coli expression systems and lactation Animal expression system to produce Fab fragments.