Monoclonal Ab or Polyclonal Antibody? Peptide or Recombinant Protein?

Previously, we got an inquiry for customized antibody. The customer asked, I want to get antibody specific to 35-55 amino acids of mouse Myelin Oligodendrocyte Glycoprotein (MOG), what kind of antibody do I need, monoclonal antibody (McAb) or polyclonal antibody? And what kind of immunogen is better for antibody preparation, peptide or recombinant protein?

In order to answer these questions, at first, let’s focus on the difference between McAb and polyclonal Ab. McAb is specific to a single epitope, and it is from immune cells that are all clones of a unique B cell. While polyclonal antibody are secreted by different B cell lineages, which identify different epitopes of antigen. Regularly, when an immunogen with lots of epitopes get into the body, their epitopes will combine with different BCR on B cells, then, these B cells will be differentiated into various plasmocytes, and these cells will secrete different kinds of antibodies specific to different epitopes. The collection of these antibodies are polyclonal antibody. But when we want to get McAb, it needs to screen B cells for specific epitope with limited dilution method, while in the experiment, commonly fusion cells are used for screening.

Secondly, we need to check the demand of the order, to get antibody specific for amino acids of 35-55. This fragment is consist of only 21 amino acid, it contains only 1-2 epitope. So, it is obviously that the specificity of antibody should be high concerned. Based on this, it is suggested that monoclonal antibody could be prepared, and the unique antibody specific to target sequence could be selected during the limited dilution process, then, the specificity of the antibody could be guaranteed.

After McAb is confirmed, we need to choose immunogen for antibody preparation. Mouse MOG is a trans-membrane protein, which contains 246 amino acids. The protein contains more than ten epitopes based on its sequence analysis. So, if the full length of recombinant protein is used as immunogen, not to mention the difficulty in expression of trans-membrane protein, the work of screening will be very hard, and the time for experiment will be really long. So, based on that, it is suggested that synthesized peptide could be used for immunogen after coupling with vector protein.

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