Affiliation:
1. Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences Moscow Russian Federation
2. FSBI – National Medical Research Center for Obstetrics, Gynecology and Perinatology named after Academician V. I. Kulakov Ministry of Health care of the Russian Federation Moscow Russian Federation
3. Kode Biotech Auckland New Zealand
4. I. M. Sechenov First Moscow State Medical University of the Ministry of Health care of the Russian Federation (Sechenov University) Moscow Russian Federation
Abstract
AbstractThe high specificity of human antibodies to blood group A and B antigens is impressive, especially when considering the structural difference between these antigens (tetrasaccharides) is a NHAc versus a hydroxyl group on the terminal monosaccharide residue. It is well established that in addition to anti‐A and anti‐B there is a third antibody, anti‐A,B capable of recognizing both A and B antigens. To analyze this AB specificity, we synthesized a tetrasaccharide, where the NHAc of the A antigen was replaced with an NH2. This NH2 group was then used to attach the glycan to an affinity resin, creating an AB epitope (ABep) adsorbent where the critical site for recognition by A and B antibodies was not accessible, while the rest of the (conformationally compact) tetrasaccharide remained accessible. Anti‐ABep antibodies were then isolated from blood group O donors and found to have expected A,B specificity against immobilized and red cell bound synthetic antigens, including ABep, and were able to agglutinate both A and B red cells. The amount of these anti‐ABep (anti‐A,B) antibodies found in the blood of group O donors was comparable to levels of anti‐A and anti‐B found in group B and A individuals. Using STD‐NMR the location for the AB epitope on the tetrasaccharide was found.