What Do You Know about the Recombinant Antibody?

Posted by Jerry Carter on January 16th, 2019

By definition, the recombinant antibody (rAb) is antibody fragments produced by use of recombinant antibody coding genes. In contrast with monoclonal antibodies (mAbs), rAbs boast a number of significant advantages. First of all, no ethical issues may get involved because no animals are used in the production process. Second, the small size of the rAb enables itself to be removed from the organism with ease and in a timely manner, if necessary. Third, the characteristic of monovalency suggests the rAb comes with high specificity. Most of all, it’s unlikely to bring about immunogenicity.

In the production process, the rAb is also advantegeous compared to traditional monoclonal antibodies derived from hybridoma cell lines. The final product can be produced in short time, and the production process is more easily controlled than the manufacturing of hybridoma cells. Moreover, the recombinant antibodies may be designed virtually against any antigen, of the proper size and shape. The fused form of recombinant antibodies may be combined with drugs and/or toxins, leading to more applications in medical research. Finally, the rAb can be optimized and genetically engineered based on the specific demand of the patient or researcher.

First, scFv fragments are fusion proteins on the variable regions of the heavy (VH) and light chains (VL) of immunoglobulins, connected with a short linker peptide of 10 to about 25 amino acids. This protein retains the specificity of the original immunoglobulin, despite removal of the constant regions and the introduction of the linker. ScFvs have many uses, e.g., for flow cytometry and immunohistochemistry, and they can serve as the antigen-binding domains of artificial T cell receptors.

Second, a Fab fragment consists of two sets of variable and constant components, which create two polypetide chains. Together they form a stable structure. As a member of the anti-idiotypic antibody, Fab fragment recombinant antibodies bind directly to the paratope of the target antibody. That means that they compete with the drug for the binding site and have an inhibitory function. Fab fragment antibodies can be used to detect not bound or free drugs in the serum, or to avoid the adverse effects caused by unspecific binding of the Fc portion of the antibody. Moreover, the recombinant Fab fragment can also be converted into the recombinant IgG form, thereby broadening the pool of potential target structures.

Third, bispecific rAbs are able to recognize two different antigens present on different cells. Since they can mediate cytotoxicity, they have been utilized as an a cellular cancer therapy. In fact, the initial study on bispecific rAbs was not satisfactory in terms of clinical results, mainly due to their low efficacy, Fc-mediated side effects and immunogenicity. This induced a falling interest in bispecific antibodies for cancer therapy. However, the growth of the understanding of effector cell biology and the implementation of antibody engineering technologies have led to a revival and the development of novel or improved strategies. Nowadays, the first recombinant antibody molecule has entered clinical trials for the treatment of B-cell malignancies.

Thanks to its high specificity and low immunogenicity, the recombinant antibody has been widely applied to the diagnosis and treatment of various diseases, while increasing the accuracy of targeting specific molecules and avoiding adverse side effects. Admittedly, their therapeutic potentials are immense. It can be thus predicted that in the future they will play a more significant role in the treatment of more diseases.

About Creative Biolabs

Creative Biolabs, a leader in recombinant antibody discovery and manufacturing, is committed to providing superior services to customers all over the world. It offers a comprehensive list of recombinant antibody products and services at the most competitive price, including antibody/peptide libraries, biosimilar cell lines, chimeric antigen receptor products, antibody-drug conjugates and engineered antibodies.