Wouldn’t it be sweet to be able to make antibodies against sugars?
The exterior cell wall of microbial pathogens are often coated in unique sugars to protect themselves from the environment. These unique polysaccharides can serve as biomarkers for infection or be the target of therapeutics. (1,2)
Antibodies are not often developed against polysaccharides, as these molecules are not retained well in the major histocompatibility complex (MHC) to be presented to T- or B-cells. (3) As a result generating antibodies against these targets can be difficult and projects are often abandoned on the premise of being too difficult to pursue. In some cases, the alternative to using antibodies may be to use lectins. Lectins are a class of proteins that bind semi-specifically to polysaccharides and can occasionally serve the purpose of a study. (4)
However, specific antibodies with high affinity are more ideal to use than lectins. As such, a method has been developed to develop anti-polysaccharide antibodies. As mentioned above, the main hurdle to overcome is to secure the polysaccharide in the MHC binding pocket to be presented to B-cells and induce anti-polysaccharide antibody production. To this end, polysaccharides are conjugated to peptides or proteins, the peptide will be retained in the MHC and the conjugated polysaccharide will be jointly presented to B-cells. (5) Following the harvesting of B-cells, the anti-polysaccharide specific antibodies can be selected for. This technique has led to the development of monoclonal antibodies that can recognize an epitope as small as a monosaccharide. (6)
The possibility of making polysaccharide specific antibodies is not as difficult as you may think. Here at MediMabs we have had great success at making these types of antibodies, do not hesitate to contact us to find out more.